3450 - Hypernatremic dehydration in children: retrospective study of 105 cases
The hypernatremic dehydration defined by a serum sodium concentration> or = to 150 mmol/l, is a particular form of acute dehydration and constitutes a medical emergency requiring a prompt and adequate diagnosis and management.
PURPOSE:
To precise the epidemiological profile, course, causes and therapeutic particularities of hypernatremic dehydration in children. POPULATION AND
METHOD:
Retrospective review of 105 children admitted in the general Paediatrics department of the Fattouma Bourguiba university hospital in Monastir (Tunisia), for hypernatremic dehydration between January 1st 1990 and December 31 2002.
RESULTS:
Hypernatremic dehydration represented 11.51% of all kinds of dehydration. The mean age was 6.5 months with a small male predominance. The socio-economic level of the parents was good in 62.8% of cases. Half of the children were in shock. Severe dehydration was present in 87.6% of cases and neurological signs were observed in 77.14% of cases. The initial mean serum sodium concentration was 159 mmol/L. Acidosis and acute renal failure were associated respectively in 97.2% and 76.2% of cases. Prominent cause of hypernatremic dehydration was diarrhoea (94.3%). Intravenous rehydration with 5% glucose solution at the average of 147 ml/kg/day and containing a mean sodium level of 42 mmol/L was performed in 74% of cases. In most cases (84.1%) serum sodium was normalized within the first 72 hours. Complications were noted in 5.7% of cases and mortality rate was 11.4%.
CONCLUSIONS:
Hypernatremic dehydration was common in infant and the prominent cause is still dominated by diarrhoea in our country. The management of hypernatremic dehydration is based on oral or intravenous rehydration and plasma expanding fluids when shock is present or imminent. The serum sodium concentration should be gradually corrected and should not exceed 0.5 mmol/L/h. Prevention is based on the pursuit of breastfeeding and the use of oral rehydration solution in infantile diarrhoeas.
La D.H.A avec hypernatrémie est fréquemment observée chez l'enfant/ elle est habituellement secondaire à une diarrhée aigue. Elle doit être corrigé par une hydratation orale ou par voie intraveineuse. Cette étude menée à Monastir en Tunisie précise que la concentration du sérum sodium doit être progressivement corrigée.3451 - Influence of mild dehydration on cognitive efficiency in schoolchildren, students and adults. Results of a nationwide multicentre study by Dortmund and Erlangen-Nurnberg Universities, Fulda College, and the Institute of Sports Nutrition and the Sport Clinic of Bad Nauheim.
A series of studies of dehydration are discussed. The conclusions are that reducing dehydration improves mental efficiency in all age groups. Calcium and magnesium rich mineral water or fruit juice drinks should be available at each meal. Children should also drink on hot days and when doing sport.
Série d'études sur l'effet de la déshydratation sur l'efficience intellectuelle. Les conclusions sont que la prise en charge de la DHA et sa diminution ont un effet mental quel que soit l'âge sur l'efficience intellectuelle.3452 - Magnesium absorption from mineral waters of different magnesium content in healthy subjects.
OBJECTIVE:
To assess the absorption of magnesium (Mg) from mineral waters of different Mg content in comparison to low mineralized water and a Mg capsule.
MATERIALS AND METHODS:
DESIGN:
Randomized, controlled, double- blind trial in a crossover design with an additional control with a Mg capsule.
SETTINGS:
Institute of Balneology and Medical Climatology, Medical School of Hanover, Germany.
SUBJECTS:
22 healthy male volunteers aged between 23-46 years.
INTERVENTION:
After a standardized breakfast, each participant received, in Latin square order, 500 ml of either of two Mg-rich mineral waters (281 or 120 mg/l). As a control condition, a mineral water of low Mg content (8 mg/l) was used. A Mg capsule (Magnesium-Diasporal 150, Protina, Ismaning, Germany) was used for further comparisons.
RESULTS:
Changes in serum Mg levels in the first 4 hours after intake differed significantly between the groups (p = 0.030/ ANOVA). Mean values differed between the Mg-rich mineral water conditions and the control conditions though did not reach statistical significance (p = 0.055), however, mean values did not differ between the test waters and the capsule (p = 0.338).
CONCLUSIONS:
Magnesium from mineral waters can easily be absorbed and its absorption rate is similar to that from a pharmaceutical Mg preparation.
3453 - Oral versus intravenous rehydration of moderately dehydrated children: A randomized, controlled trial.
BACKGROUND:
Dehydration from viral gastroenteritis is a significant pediatric health problem. Oral rehydration therapy (ORT) is recommended as first line therapy for both mildly and moderately dehydrated children/ however, three quarters of pediatric emergency medicine physicians who are very familiar with the American Academy of Pediatrics recommendations for ORT still use intravenous fluid therapy (IVF) for moderately dehydrated children.
OBJECTIVE:
To test the hypothesis that the failure rate of ORT would not be >5% greater than the failure rate of IVF. Secondary hypotheses were that patients in the ORT group will (1) require less time initiating therapy, (2) show more improvement after 2 hours of therapy, (3) have fewer hospitalizations, and (4) prefer ORT for future episodes of dehydration.
METHOD:
A randomized, controlled clinical trial (noninferiority study design) was performed in the emergency department of an urban children''s hospital from December 2001 to April 2003. Children 8 weeks to 3 years old were eligible if they were moderately dehydrated, based on a validated 10-point score, from viral gastroenteritis. Patients were randomized to receive either ORT or IVF during the 4-hour study. Treating physicians were masked and assessed all patients before randomization at 2 and 4 hours of therapy. Successful rehydration at 4 hours was defined as resolution of moderate dehydration, production of urine, weight gain, and the absence severe emesis ((greater-than or equal to5 mL/kg).
RESULTS:
Seventy-three patients were enrolled in the study: 36 were randomized to ORT and 37 were randomized to IVF. Baseline dehydration scores and the number of prior episodes of emesis and diarrhea were similar in the 2 groups. ORT demonstrated noninferiority for the main outcome measure and was found to be favorable with secondary outcomes. Half of both the ORT and IVF groups were rehydrated successfully at 4 hours (difference: -1.2%/ 95% confidence interval (CI): -24.0% to 21.6%). The time required to initiate therapy was less in the ORT group at 19.9 minutes from randomization, compared with 41.2 minutes for the IVF group (difference: -21.2 minutes/ 95% CI: -10.3 to -32.1 minutes). There was no difference in the improvement of the dehydration score at 2 hours between the 2 groups (78.8% ORT vs 80% IVF/ difference: -1.2%/ 95% CI: -20.5% to 18%). Less than one third of the ORT group required hospitalization, whereas almost half of the IVF group was hospitalized (30.6% vs 48.7%, respectively/ difference: -18.1%/ 95% CI: -40.1% to 4.0%). Patients who received ORT were as likely as those who received IVF to prefer the same therapy for the next episode of gastroenteritis (61.3% vs 51.4%, respectively/ difference: 9.9%/ 95% CI: -14% to 33.7%).
CONCLUSION:
This trial demonstrated that ORT is as effective as IVF for rehydration of moderately dehydrated children due to gastroenteritis in the emergency department. ORT demonstrated noninferiority for successful rehydration at 4 hours and hospitalization rate. Additionally, therapy was initiated more quickly for ORT patients. ORT seems to be a preferred treatment option for patients with moderate dehydration from gastroenteritis.
Etude randomisée du traitement de la D.H.A moderne par voie orale ou par perfusion I.V. La réhydratation par voie orale semble devoir être préférée dans ce type de DHA.3454 - Water drinking improves orthostatic tolerance in patients with posturally related syncope
Water drinking improves OT (orthostatic tolerance) in healthy volunteers/ however, responses to water in patients with PRS (posturally related syncope) are unknown. Therefore the aim of the present study was to examine whether water would improve OT in patients with PRS. In a randomized controlled cross-over fashion, nine patients with PRS ingested 500 ml and 50 ml (control) of water 15 min before tilting on two separate days. OT was determined using a combined test of head-up tilting and lower body suction and expressed as the time required to induce presyncope. We measured blood pressure and heart rate (using Portapres Registered) and middle cerebral artery velocity (using transcranial Doppler). SV (stroke volume) and TPR (total peripheral resistance) were calculated using the Modelflow Registered method. OT was significantly (P < 0.02) greater after drinking 500ml of water than after 50ml (25.4+-1.5 compared with 19.8+-2.3 min respectively). After ingestion of 500 ml of water, blood pressure during tilting was higher, the tilt-induced reduction in SV was smaller and the increase in TPR was greater (all P < 0.05). The correlation coefficient of the relationship between cerebral blood flow velocity and pressure was lower after 500 ml of water (0.43 +- 0.1 compared with 0.73 +- 0.1/ P < 0.05), indicating better autoregulation
IN CONCLUSION:
drinking 500 ml of water increased OT and improved cardiovascular and cerebrovascular control during orthostasis. Patients with PRS should be encouraged to drink water before situations likely to precipitate a syncopal attack
3455 - Magnesium in drinking water and cardio-vascular disease--an epidemiological dilemma.
The relation between drinking water and cardiovascular disease has been evaluated in a number of studies. Certain of these show strong relationships whereas others do not. This review analyses the methodological aspects on epidemiological studies in terms of dose-range, confounding factors and multiple exposures. It is concluded that there is good evidence for a relation between drinking water quality and cardio-vascular disease, that several methodological criteria for such studies need to be considered, that there is little evidence for magnesium as the single causative agent, and that the relevant exposure should be considered as a mixture of minerals.
3456 - The effects of cranberry juice consumption on antioxidant status and biomarkers relating to heart disease and cancer in healthy human volunteers.
Background Consumption of fruit and vegetables is associated with a decreased risk of heart disease and cancer. This has been ascribed in part to antioxidants in these foods inactivating reactive oxygen species involved in initiation or progression of these diseases. Non-nutritive anthocyanins are present in significant amounts in the human diet. However, it is unclear whether they have health benefits in humans
AIMS:
To determine whether daily consumption of anthocyanin-rich cranberry juice could alter plasma antioxidant activity and biomarkers of oxidative stress
METHOD:
20 healthy female volunteers aged 18-40y were recruited. Subjects consumed 750 ml/day of either cranberry juice or a placebo drink for 2 weeks. Fasted blood and urine samples were obtained over 4 weeks. The total phenol, anthocyanin and catechin content of the supplements and plasma were measured. Anthocyanin glycosides were identified by tandem mass spectrometry (MS-MS).Vitamin C, homocysteine (tHcy) and reduced glutathione (GSH) were measured by HPLC. Total antioxidant ability was determined using electron spin resonance (ESR) spectrometry and by the FRAP assay. Plasma total cholesterol, high density lipoprotein (HDL), and low density lipoprotein (LDL) cholesterol and triglycerides (TG) were measured. Glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD) activities were measured in erythrocytes. Urine was collected for analysis of malondialdehyde (MDA) by HPLC and 8-oxo-deoxyguanosine (8-oxo-dG) by ELISA. Endogenous and induced DNA damage were measured by single cell gel electrophoresis (SCGE) in lymphocytes
RESULTS:
Vitamin C, total phenol, anthocyanin and catechin concentrations and FRAP and ESR values were significantly higher in the cranberry juice compared with the placebo. Cyanidin and peonidin glycosides comprised the major anthocyanin metabolites (peonidin galactoside (29.2 %) > cyanidin arabinoside (26.1 %) > cyanidin galactoside (21.7%) > peonidin arabinoside (17.5%) > peonidin glucoside (4.1 %) > cyanidin glucoside (1.4 %)). Plasma vitamin C increased significantly (P < 0.01) in volunteers consuming cranberry juice. No anthocyanins (plasma) or catechins (plasma or urine) were detectable and plasma total phenols, tHcy, TC, TG, HDL and LDL were unchanged. The antioxidant potential of the plasma, GSH-Px, CAT and SOD activities, and MDA were similar for both groups. Supplementation with cranberry juice did not affect 8-oxo-deoxyguanosine in urine or endogenous or H2O2-induced DNA damage in lymphocytes
CONCLUSION:
Cranberry juice consumption did not alter blood or cellular antioxidant status or several biomarkers of lipid status pertinent to heart disease. Similarly, cranberry juice had no effect on basal or induced oxidative DNA damage. These results show the importance of distinguishing between the in vitro and in vivo antioxidant activities of dietary anthocyanins in relation to human health.
3457 - Cardiovascular responses to water drinking: does osmolality play a role?
Water drinking activates the autonomic nervous system and induces acute hemodynamic changes. The actual stimulus for these effects is undetermined but might be related to either gastric distension or to osmotic factors. In the present study, we tested whether the cardiovascular responses to water drinking are related to water''s relative hypoosmolality. Therefore, we compared the cardiovascular effects of a water drink (7.5 ml/kg body wt) with an identical volume of a physiological (0.9%) saline solution in nine healthy subjects (6 male, 3 female, aged 26 +/- 2 years), while continuously monitoring beat-to-beat blood pressure (finger plethysmography), cardiac intervals (electrocardiography), and cardiac output (thoracic impedance). Total peripheral resistance was calculated as mean blood pressure/cardiac output. Cardiac interval variability (high-frequency power) was assessed by spectral analysis as an index of cardiac vagal tone. Baroreceptor sensitivity was evaluated using the sequence technique. Drinking water, but not saline, decreased heart rate (P = 0.01) and increased total peripheral resistance (P < 0.01), high-frequency cardiac interval variability (P = 0.03), and baroreceptor sensitivity (P = 0.01). Neither water nor saline substantially increased blood pressure. These responses suggest that water drinking simultaneously increases sympathetic vasoconstrictor activity and cardiac vagal tone. That these effects were absent after drinking physiological saline indicate that the cardiovascular responses to water drinking are influenced by its hypoosmotic properties.
3458 - Magnesium intake and incidence of metabolic syndrome among young adults.
BACKGROUND:
Studies suggest that magnesium intake may be inversely related to risk of hypertension and type 2 diabetes mellitus and that higher intake of magnesium may decrease blood triglycerides and increase high-density lipoprotein (HDL) cholesterol levels. However, the longitudinal association of magnesium intake and incidence of metabolic syndrome has not been investigated.
METHOD AND RESULTS:
We prospectively examined the relations between magnesium intake and incident metabolic syndrome and its components among 4637 Americans, aged 18 to 30 years, who were free from metabolic syndrome and diabetes at baseline. Metabolic syndrome was diagnosed according to the National Cholesterol Education Program/Adult Treatment Panel III definition. Diet was assessed by an interviewer-administered quantitative food frequency questionnaire, and magnesium intake was derived from the nutrient database developed by the Minnesota Nutrition Coordinating Center. During the 15 years of follow-up, 608 incident cases of the metabolic syndrome were identified. Magnesium intake was inversely associated with incidence of metabolic syndrome after adjustment for major lifestyle and dietary variables and baseline status of each component of the metabolic syndrome. Compared with those in the lowest quartile of magnesium intake, multivariable-adjusted hazard ratio of metabolic syndrome for participants in the highest quartile was 0.69 (95% confidence interval [CI], 0.52 to 0.91/ P for trend <0.01). The inverse associations were not materially modified by gender and race. Magnesium intake was also inversely related to individual component of the metabolic syndrome and fasting insulin levels.
CONCLUSION:
Our findings suggest that young adults with higher magnesium intake have lower risk of development of metabolic syndrome.
3459 - Sodium bicarbonated mineral water decreases postprandial lipaemia in postmenopausal women compared to a low mineral water.
The role of bicarbonated mineral waters on lipid metabolism and lipoprotein concentrations in man has scarcely been investigated. The present study aimed to investigate whether drinking sodium bicarbonated mineral water affects postprandial cholesterol and triacylglycerol metabolism in postmenopausal women. In a three-way, randomised, crossover study, eighteen healthy postmenopausal women consumed two sodium bicarbonated mineral waters (bicarbonated mineral water 1 and bicarbonated mineral water 2) and a low mineral water (500 ml of each) with a standard fat-rich meal (4552 kJ/ 75.3 g fat). The bicarbonated waters were rich in sodium and bicarbonate and bicarbonated mineral water 1 contained 5.7 times more fluoride than bicarbonated mineral water 2. Fasting blood samples and postprandial blood samples were taken at 30, 60, 120, 240, 360 and 420 min after the end of the meal consumption. Cholesterol and triacylglycerols were determined in serum and chylomicrons. A significant water consumption effect was observed in the total area under the curve (TAUC) of serum and chylomicron triacylglycerols (ANOVA, P=0.008 and P=0.027, respectively). TAUC of serum triacylglycerols for bicarbonated mineral water 2 was significantly lower compared to low mineral water (Bonferroni, P=0.039). Peak concentration of serum triacylglycerols showed a significant water effect (P=0.025). Changes in chylomicron cholesterol were not significantly affected by the type of water. Bicarbonated mineral waters 1 and 2 did not show any significant differences. Drinking sodium bicarbonate-rich mineral waters reduces postprandial lipaemia in healthy postmenopausal women compared to drinking a low mineral water.
3460 - Long-term follow-up of workplace and well water manganese effects on iron status indexes in manganese miners.
The authors assessed the effect of water reconstitution in the workplace by evaluating the iron status of manganese mine workers during a long-term study. Subsequent analyses and biological monitoring were performed in a group of 150 manganese miners before, and 2.8 yr after, reconstitution of drinking water in the miners'' workplace. The authors found significantly high concentrations of manganese in the workplace well water, as well as in the miners'' blood, urine, and hair. There was a considerable prevalence of epithelial lesions, which resulted from iron deficiency, in the miners, compared with controls. The authors assessed the prevalence of iron deficiency grades (i.e., I > II > III > IV) before and after water reconstitution. Reconstitution of drinking water for the ultimate attainment of healthy levels of manganese and other minerals resulted in a significant improvement in the miners'' iron status and a decreased prevalence of epithelial lesions. The authors concluded that alterations in iron status may result from the cumulative effect of high levels of manganese in consumed water, as well as in airborne dust, in the workplace. Such elevated levels should be considered as an occupational hazard because they have an ability to interfere with iron absorption.
Une trop grande quantité de manganèse dans l’eau de boisson, cumulée à son absorption par voie pulmonaire en cas d’exposition professionnelle chez les mineurs, pourrait avoir un retentissement négatif sur le statut martial.3461 - Nickel sensitization as a possible cofactor in chronic fatigue syndrome.
The chronic fatigue syndrome (CFS) is a multifactorial disease. Metal sensitisation has been, at least partly, implicated as a causal or symptom-aggravating factor. In a pilot study, 32 patients with CFS have been investigated for the existence of sensitisation toward 15 different metals by means of a standardized and optimised lymphocyte proliferation test (LTT). 14 patients (44 %) were shown to react against nickel (normal population prevalence 12 %). In order to elicit a causal role for the sensitisation, the patients were advised to follow a nickel-poor diet over 4 weeks. Symptoms of CFS were reduced to a large extent in 4 patients (diet responders) while 2 patients exhibited a partial remission (diet partial responders). The diet did not have an effect in 8 patients (diet non-responders). Responders and partial responders presented with high nickel stimulation indices before diet. After a 4-week nickel-poor diet, however, a considerable drop of the nickel stimulation index was observed in these patients. In contrast, no changes in the anyway low starting values were observed in the diet non-responders. The LTT test provides evidence for an existing sensitisation as well as for a current allergen exposure. The results of this study point to the fact that nickel, a widespread allergen in the environment, food and beverages, is potentially responsible for the chronic fatigue syndrome and its diverse manifestations.
Un excès d’apport de nickel par l’alimentation pourrait favoriser le syndrome de fatigue chronique.3462 - A one-quarter reduction in the salt content of bread can be made without detection.
OBJECTIVE:
To determine if it is possible to deliver a one-quarter reduction in the sodium content of bread without detection.
DESIGN:
Single-blind, randomized, controlled trial.
SETTINGS:
The Royal North Shore Hospital in Sydney, Australia.
PARTICIPANTS:
One-hundred and ten volunteers from the hospital staff that completed 94% of scheduled assessments.
INTERVENTION:
Six consecutive weeks of bread with usual sodium content or six consecutive weeks of bread with cumulating 5% reductions in sodium content each week.
MAIN OUTCOME MEASURES:
The proportion of participants reporting a difference in the salt content of the study bread from week to week.
RESULTS:
The intervention group were no more likely than the control group to report a difference in the salt content of the bread from week to week (P=0.8). Similarly, there were no differences between randomized groups in the scores for flavour (P=0.08) or liking of the bread (P=0.95) over the study follow-up period. However, the saltiness scores recorded on a visual analogue scale did decline in the intervention group compared with the control group (P=0.01)
CONCLUSION:
A one-quarter reduction in the sodium content of white bread can be delivered over a short time period, while maintaining consumer acceptance. Over the long term, and particularly if achieved for multiple foods, a decrease in sodium content of this magnitude would be expected to reduce population levels of blood pressure and the risks of stroke and heart attack.
Une modération de la consommation de sel, excessive dans les pays occidentaux, est considérée comme souhaitable pour réduire le risque d’hypertension artérielle et de maladies cardiovasculaires. Dans ce but, il est proposé de réduire la teneur en sel des aliments, notamment du pain. Les auteurs ont recherché s’il était possible de réduire de 25 % en 6 semaines la teneur en sel du pain sans entraîner de rejet de sa consommation. L’étude a porté sur 110 volontaires, qui ont été affectés par randomisation à consommer pendant 6 semaines soit leur pain habituel, soit le même pain mais avec une teneur en sel réduite de 5 % de semaine en semaine. Au cours de l’étude, aucune différence dans le goût salé du pain n’a été perçue et, à la fin de l’étude, il n’est apparu aucune différence significative entre les deux groupes en ce qui concerne les scores appréciant la saveur du pain et l’appétence pour sa consommation. Cette étude, de méthodologie rigoureuse et objective, montre qu’il est possible de réduire sensiblement la teneur en sel du pain, source important d’apport en sodium dans les pays occidentaux, sans en altérer la saveur et sans gêner l’acceptabilité.3463 - Mild dehydration: A risk factor of constipation?
Constipation defined as changes in the frequency, volume, weight, consistency and ease of passage of the stool occurs in any age group. The most important factors known to promote constipation are reduced physical activity and inadequate dietary intake of fibres, carbohydrates and fluids. Fluid losses induced by diarrhoea and febrile illness alter water balance and promote constipation. When children increase their water consumption above their usual intake, no change in stool frequency and consistency was observed. The improvement of constipation by increasing water intake, therefore, may be effective in children only when voluntary fluid consumption is lower-than- normal for the child''s age and activity level. In the elderly, low fluid intake, which may be indicative of hypohydration, was a cause of constipation and a significant relationship between liquid deprivation from 2500 to 500 ml per day and constipation was reported. Dehydration is also observed when saline laxatives are used for the treatment of constipation if fluid replacement is not maintained and may affect the efficacy of the treatment. While sulphate in drinking water does not appear to have a significant laxative effect, fluid intake and magnesium sulphate-rich mineral waters were shown to improve constipation in healthy infants
IN CONCLUSION:
fluid loss and fluid restriction and thus de-or hypohydration increase constipation. It is thus important to maintain euhydration as a prevention of constipation.
La constipation est fréquente. Chez l'enfant notamment après de grandes pertes d'eau (fièvre, diarrhée...), chez la personne âgée (état d'hypohydratation latent) et chez les personnes qui équilibrent mal leurs apports avec leurs dépenses/pertes -(femme enceinte par exemple). Toute restriction d'apport en eau, chez un sujet sain ayant une diététique et une activité physique suffisantes, va ralentir le transit et favoriser la constipation. La prise d'eau et particulièrement d'eau minérale riche en magnesium lutte efficacement contre la constipation.3464 - Changes in abdominal subcutaneous fat water content with rapid weight loss and long-term weight maintenance in abdominally obese men and women.
OBJECTIVE:
Insulin resistance decreases blood flow and volume in fat tissue. We hypothesised that fat tissue nutritive blood flow and volume, and thereby water content, would increase during weight loss and weight maintenance in obese persons.
DESIGN:
Longitudinal clinical intervention with a 9-week very-low-calorie diet (VLCD) followed by one year of weight maintenance.
SUBJECTS:
Obese men (n=13) and women (n=14) with the metabolic syndrome.
MEASUREMENTS:
Water content of abdominal subcutaneous fat tissue as estimated by a sensor on the skin surface measuring the dielectric constant at 300 MHz. Anthropometric measures of fatness and fat distribution. Biochemical measures related to insulin resistance.
RESULTS:
Subjects lost 14.5+/-3.4% of body weight during the VLCD, and generally sustained this weight loss during weight maintenance. Insulin sensitivity as estimated by an index (qualitative insulin sensitivity check index) increased during the VLCD, and remained increased throughout weight maintenance. The dielectric constant increased from 23.3+/-2.3 to 25.0+/-2.1 (P<0.001) during the VLCD, and further to 27.8+/-1.9 (P<0.001) during weight maintenance, indicating an increase in the water content of subcutaneous fat. The increase in subcutaneous fat water content did not correlate with weight loss and other measures of adiposity during the VLCD, but there was an inverse correlation that strengthened in significance from baseline to 6, 9 and 12 mo (r=-0.32 to -0.64, P=0.079-0.002). Increases in subcutaneous fat water content also correlated with improvements in insulin sensitivity at 6, 9 and 12 months of weight maintenance (r=0.34-0.54, P=0.094-0.006).
CONCLUSION:
Water content of abdominal subcutaneous adipose tissue increases with weight loss in obese persons with the metabolic syndrome, and may reflect increased subcutaneous fat tissue nutritive blood flow. The increase in water content correlates with the increase in insulin sensitivity, suggesting that weight loss and consequent improved insulin sensitivity could mediate the increase in abdominal subcutaneous fat hydration.
Ce travail montre que l’amaigrissement, par un régime très restrictif de patient (13 H et 14 F) atteints de syndrome métabolique, entraîne une augmentation du contenu en eau du tissu adipeux sous-cutané correspondant possiblement à une augmentation du débit sanguin dans ce tissu. Cette évolution est associée à la réduction de l’insulino-résistance. 3465 - Dental health behavior, gastroesophageal disorders and dietary habits among Norwegian recruits in 1990 and 1999.
A questionnaire was given to representative samples of Norwegian recruits in 1990 and 1999 to explore dental health habits, history of gastroesophageal disorders and diet with possible relations to dental erosion. The samples were 792 (mean age 20.9 years) and 676 (mean age 21.6 years), respectively, and the corresponding responses were 62% and 100%. Minor differences in self-reported dental health habits and gastroesophageal disorders were found. The respondents'' dentists had provided information about dental erosion for 8.2% of the respondents in 1990 versus 14.5% in 1999. There was an increase in the reported frequency of daily intake of juice from 17% to 24% (P = 0.006) and carbonated soft drink from 54% to 61% (P = 0.025) in the period 1990-99. The frequency of training activity showed minor changes, but in 1999 it was more common to drink during exercise (94% versus 74% in 1990, P < 0.001), and the majority drank water. Sixteen percent of recruits ate oranges daily in 1990/ in 1999 this had dropped to 11% (P = 0.012). The corresponding proportion that ate apples daily had dropped from 17% to 8% in the period (P < 0.001). It is likely that lifestyle factors related to diet among young men have changed in the period 1990-99 in a direction that may increase the prevalence of dental erosions.
L'étude faite en Suède sur les jeunes recrues en 1990 et 1999, jeunes hommes de 20-21 ans deux cohortes, le but est d'évaluer les relations éventuelles entre les habitudes d'hygiène dentaire, les troubles digestifs, l'alimentation et les caries. L'enquête est faite par questionnaire, les résultats montrent qu'en 1990 on ne note pas de différence entre les deux cohortes.
Par contre il y a des différences importantes entre les deux études à 10 ans d'intervalle. Les caries ont augmenté de 8 % à 15 % entre 1990 et 1999, c'est éventuellement les modifications alimentaires, l'absorption de boissons sucrées et acides. C'est probablement ces changements d'habitudes qui sont la cause de l'augmentation des caries.3466 - Mild dehydration: A risk factor of broncho-pulmonary disorders?
Several expert committees recommend a high fluid intake in patients with chronic bronchitis and asthma. Is there a relationship between fluid intake or hydration status and broncho-pulmonary disorders like bronchitis and asthma? First, basic physiologic mechanisms like regulation of lung fluid balance and water transport at pulmonary surfaces were analyzed, in order to characterize the role of local hydration status in lung and airways. Second, making use of the computer-based literature searches (PubMed), evidence for a role of hydration status in complex physiological and pathophysiological conditions of lungs and airways like perinatal lung adaptation (PLA) (in prematures), mucociliary clearance(MC) and asthma was categorized. The movement of fluid between the airspaces, interstitium, and vascular compartments in the lungs plays an important physiological role in the maintenance of hydration and protection of the lung epithelium and significantly contributes to a proper airway clearance. PLA is characterized by a rapid change from fluid secretion to fluid absorption in the distal respiratory tract, with the literature data confirming a critical role of the epithelial sodium channel. Only few studies have investigated the effect of different fluid input regimens on PLA in prematures. MC relies on the interaction between epithelial water fluxes, mucus secretions, and ciliary activity. Whereas animal data show that drying of the airway epithelium decreases MC, few clinical studies investigating the effect of local or systemic hydration on MC have led to ambiguous results. Asthma (A) is characterized by chronic airway inflammation and episodic airway obstruction. Data in animals and humans indicate an association between exercise-induced-A and conditioning (humidity and heat exchange) of inspired air. However, epidemiological studies (children and adults), investigating the role of fluid (and salt) input in the etiology of the disease as well as studies analyzing different markers of hydration status during asthmatic attacks have so far led to conflicting results. Some expert groups recommend sufficient hydration as a complementary A-therapy. Analysis of basic physiological mechanisms in lungs and airways clearly demonstrates a critical role for water transport and local hydration status. In broncho-pulmonary diseases, however, analysis of the complex pathophysiological mechanisms is difficult. Thus, we still need more studies to confirm or refute mild dehydration or hypohydration as a risk factor of broncho-pulmonary disorders.
La plupart des experts recommandent l'absorption de grandes quantités d'eau en cas d'asthme ou de bronchite chronique. Si les effets de la prise d'eau sur la clinique de ces pathologies sont démontrés, les mécanismes physiopathologiques ne le sont pas. L'eau bue agit certainement sur les voies aériennes et les poumons / par contre les mécanismes demandent d'autres études.3467 - Mild dehydration: A risk factor for dental disease?
A review of the published international literature was undertaken to investigate whether dehydration is a risk factor for dental disease. Published evidence of associations between saliva and dental disease and between saliva and dehydration was observed, but the precise nature of these associations is unclear and no evidence of a direct link between dehydration and dental disease was found. It is concluded that no direct link between dehydration and dental disease has been proven, although there is considerable circumstantial evidence to indicate that such a link exists.
Est ce que l'état de deshydratation constitue un facteur de risque pour les maladies dentaires ?
Cette question peut être soulevée sur la base de rapports entre l'état de la salive et les dents, on ne connait pas de mécanisme pouvant jouer un rôle mais il est possible qu'un lien existe.3468 - Mild dehydration: A risk factor of urinary tract infection?
Bacterial growth in the urinary tract is usually prevented by host factors including bacterial eradication by urinary and mucus flow, urothelial bactericidal activity, urinary secretory IgA, and blood group antigens in secretions which interfere with bacterial adherence. Bacterial eradication from the urinary tract is partially dependent on urine flow and voiding frequency. Therefore, it seems logical to postulate a connection between fluid intake and the risk of urinary tract infections (UTIs). However, experimental and clinical data on this subject are conflicting. Experimental studies concerning the effect of water intake on susceptibility and course of UTIs were predominantly performed in the 60 s and 70 s. Despite many open questions, there has been no continuous research in this field. Only few clinical studies producing contradictory results are available on the influence of fluid intake concerning the risk of UTI. One explanation for the inconsistency between the data might be the uncertainty about the exact amounts of fluid intake, which was mostly recorded in questionnaires. So far, there is no definitive evidence that the susceptibility for UTI is dependent on fluid intake. Nevertheless, adequate hydration is important and may improve the results of antimicrobial therapy in UTI
RESULTS:
of experimental and clinical studies concerning urinary hydrodynamics are the basis for advice given by expert committees to patients with UTI to drink large volumes of fluid, void frequently, and completely empty the bladder. The combination of the behaviourally determined aspects of host defence and not simply increasing fluid intake is important in therapy and prophylaxis of UTI.
L’auteur réexamine l’efficacité de la classique recommandation de boire abondamment pour prévenir les rechutes d’infection urinaire. En effet, les cystites (qui traduisent une infection de la vessie) sont très fréquentes chez la femme et ont souvent tendance à récidiver. Sachant que les germes pénètrent dans la vessie à partir des muqueuses du périnée et que la minime quantité d’urine restant dans la vessie après la miction constitue un milieu de culture permettant leur multiplication en quelques heures, on conçoit que les mesures contribuant à éviter la stagnation des urines dans la vessie sont essentielles pour prévenir la récidive des infections urinaires. Toutes les recommandations des experts urologues concordent pour préconiser trois mesures préventives simples : 1) boire abondamment pour augmenter le débit des urines / 2) vider fréquemment la vessie, au moins toutes les 4 heures pendant la journée, pour ne pas laisser aux germes le temps de se multiplier / 3) s’efforcer de vider complètement la vessie à chaque miction. Ces mesures sont à instituer en même temps que le traitement antibactérien et à poursuivre ensuite régulièrement.3469 - Drinking water hardness and chronic degenerative diseases. II. Cardiovascular diseases
Since the 1950s a causal relation between water hardness and cardiovascular diseases (CVD) in humans has been hypothesized. In order to evaluate the influence of calcium and magnesium, the minerals responsible for the hardness of drinking water, on human health, a review of all the articles published on the subject from 1980 up to today has been carried out. Many but not all geographic correlation studies showed an inverse association between water hardness and mortality for CVD. Most case-control and one cohort studies showed an inverse relation, statistically significant, between mortality from CVD and water levels of magnesium, but not calcium. Consumption of water containing high concentrations of magnesium seems to reduce of about 30-35% the mortality for CVD, but not the incidence. This inverse association is supported by clinical and experimental findings and is biologically plausible and in line with Hill''s criteria for a cause-effect relationship.
3470 - Fluid and electrolyte balance: how do junior doctors measure up?
Fluid and electrolyte disorders are common in hospital patients and can cause serious complications, especially in the elderly. The task of fluid management is often left to the most junior members of the team, the senior house officer and the preregistration house officer. However, the level of teaching and support available to them in this regard appears to be unsatisfactory.
3471 - Magnesium and calcium in drinking water and cardiovascular mortality.
Data on the hardness of drinking water were collected from 27 municipalities in Sweden where the drinking water quality had remained unchanged for more than 20 years. Analyses were made of the levels of lead, cadmium, calcium, and magnesium. These water-quality data were compared with the age-adjusted mortality rate from ischemic heart and cerebrovascular disease for the period 1969-1978. Lead and cadmium were not present in detectable amounts except in one water sample. A statistically significant inverse relationship was present between hardness and mortality from cardiovascular disease for both sexes. Mortality caused by ischemic heart disease was inversely related to the magnesium content, particularly for the men (P less than 0.01). The rather small set of data supports results from previous studies suggesting that a high magnesium level in drinking water reduces the risk for death from ischemic heart disease, especially among men, although the possible importance of confounding factors needs further evaluation.
3472 - Dehydration impairs vigilance related attention in male basketball players.
PURPOSE: To determine the effects of dehydration (DEH) on attentional vigilance in male basketball players. METHODS: The Test of Variables of Attention (TOVA/ Universal Attention Disorders) was administered to 11 male basketball players (17 28 yr) at baseline (test 1), after walking (50% VO2max) in the heat (40°C and 20% relative humidity) (test 2), and then after a simulated basketball game (test 3). Tests 2 and 3 were performed while subjects were either DEH (1 4%) or euhydrated (EUH). The TOVA consisted of target infrequent and target frequent conditions, simulating static and dynamic (such as a basketball game) environments, respectively. TOVA measures included errors of omission (OE) and commission (CE), response time (RT), and sensitivity. RESULTS: During the target infrequent half of test 3, EUH resulted in significantly better sensitivity (+0.4 ± 1.2 vs. 0.9 ± 1.3), faster RT (8 ± 20 vs. +16 ± 28), and fewer OE (0.4 ± 0.7 vs. +1.3 ± 2.4) compared with DEH. During the target frequent half, EUH resulted in significantly fewer OE (4 ± 15 vs. +5 ± 7) and CE (1.9 ± 3.2 vs. 0.6 ±1.4) in test 2 and greater sensitivity (+0.7 ± 2.6 vs. 0.7 ± 1.1) and faster RT (21 ± 28 vs. +5 ± 31) than DEH in test 3. CONCLUSION: Vigilance related attention of male basketball players was impaired by DEH, especially during the target frequent condition of the TOVA. These results suggest that fluid replacement is essential to prevent the decline in vigilance that occurs with DEH in highly dynamic environments. Therefore, basketball players should be advised to maintain EUH for optimal concentration and attentional skills during competition.
3473 - The effect of marathon cycling on renal function.
The stress of strenuous long-term exercise may alter renal function. Whether this is also true for marathon cycling is unknown so far. The purpose of this study was to evaluate renal function following competitive marathon cycling. We investigated 38-male, well-trained recreational cyclists credibly not taking any kind of doping who participated in the Otztal Radmarathon. Blood and urine specimens were taken the day before, immediately after and one day after competition. Baseline renal functional parameters--normal before competition--increased significantly afterwards and remained elevated during 24 hours of recovery. The rises in serum creatinine, urea and uric acid were 20, 54 and 42 % (p < 0.001 respectively). The corresponding decline in estimated creatinine clearance was 18 %. In all athletes the serum urea/creatinine ratio rose above 40, fractional sodium excretion and fractional uric acid excretion fell below 0.4 % and 15 %, indicating reduced renal perfusion. The observed effects lasted for at least 24 h despite a stable fluid balance during the race and an expanding plasma volume (PV) in the recovery period. Levels of haematocrit remained unchanged immediately post-race but significantly declined from 0.44 to 0.41 on the following day (p < 0.001). The calculated rise in PV was + 10.8 %. Electrolyte homeostasis was preserved throughout the observation period. Post-exercise proteinuria was small and of the mixed glomerular-tubular type. There was neither evidence for exercise-induced haemolysis, nor for significant skeletal muscle damage. The finding obtained from well-hydrated recreational athletes reveals that the extraordinary strains of marathon cycling influence renal function only on a minimal scale. Though minor, the physiological effects were long-lasting. The results obtained suggest that a reduced renal perfusion is the mechanism responsible for the slight impairment of renal function following exhaustive marathon cycling.
Le stress lié à un exercice intense et de longue durée est susceptible d’altérer la fonction rénale. Les auteurs le vérifient lors d’exercice de marathons cyclistes en observant des modifications légères de la fonction rénale traduisant une baisse de la perfusion du rein : baisse de la clairance de la créatinine, accompagnée d’une augmentation de 20% de la créatinémie, augmentation de l’urée (+54%) et de l’acide urique (+42%) sérique, baisse de l’élimination urinaire de l’acide urique et du Na+. Ces modifications interviennent en dépit d’une balance des fluides stable au cours de l’exercice / elles se maintiennent pendant 24h après l’exercice malgré une expansion du volume plasmatique (+11%). On notera que l’homéostasie des électrolytes est restée préservée pendant l’exercice et au cours de la période de récupération.3474 - Dehydration of football referees during a match.
OBJECTIVE:
To study hydration status in referees (main) and assistant referees (linesmen) during official football matches.
METHOD:
Twelve male football referees were evaluated/ all were volunteers. Before and after each match, the referee and one of the assistants were weighed without clothes and a blood sample was taken. Total water loss was determined for each subject from the change in body weight. The main haematological variables were analysed in the blood samples. Total plasma protein concentration and osmolarity were also determined. Variation in plasma volume was determined from changes in packed cell volume and a combination of changes in packed cell volume and haemoglobin concentrations.
RESULTS:
During a match, total body water loss was 1.60 (0.13) litres, equivalent to 2.05 (0.18)% of body weight. Body weight was reduced by 1.55 (0.12)%, showing that water ingestion during the interval replaces only 24.4% of the body fluids lost during the match. The assistants lost 0.79 (0.19) litre of water, equivalent to 1.05 (0.25)% of body weight. The referees showed a significant decrease in plasma volume of 4.99 (1.33)%. The assistants showed a non-significant increase in plasma volume. The reduction in plasma volume observed in the referees correlated significantly with total body water loss (r = 0.9623). From these data, it is possible to predict that a dehydration of 1% reflects a reduction in plasma volume of nearly 2.5%.
CONCLUSION:
Referees are moderately dehydrated after a football match (2%), whereas assistants show a non-significant dehydration of 1% of their body weight.
Cette expérimentation a évalué le statut d’hydratation des arbitres au cours de matches de football. La perte en eau moyenne a été de 2% du poids corporel, avec une baisse de près de 5% du volume plasmatique / la restauration spontanée des pertes hydriques au cours du matche est d’environ ¼ des pertes. Les arbitres de ligne perdent deux fois moins d’eau.3475 - Physician misdiagnosis of dehydration in older adults.
INTRODUCTION:
Dehydration is a difficult clinical diagnosis in older adults because the physical signs of dehydration are often confusing. The clinical consequences of a diagnosis of dehydration are critical, since dehydration implies increased morbidity and mortality and aggressive rehydration can improve clinical outcome. The diagnosis is a sentinel event for nursing homes, and often is made at transfer to a hospital.
OBJECTIVE:
To define the accuracy of the clinical diagnosis of dehydration during hospital admission, and to observe persons admitted from long-term care.
METHOD:
A total of 102 consecutive medical admissions in persons older than 65 years with a diagnostic coding for dehydration either on admission or during the course of hospitalization over a 3-month period at a university teaching hospital were reviewed. The diagnosis of dehydration was considered confirmed if the calculated serum osmolarity was greater than 295 milliosmols (mOsmol). Subjects were considered to have intravascular volume depletion if the ratio of blood urea nitrogen (BUN) to serum creatinine was greater than 20 or the serum sodium was greater than 145 milligrams per deciliter. Subjects were considered to have hypovolemia if the serum osmolarity was greater than 295 and the BUN/creatinine ratio was greater than 20.
RESULTS:
Among subjects with a clinical diagnosis of dehydration, only 17% had a serum osmolarity >295 m Osm, and only 11% had a serum sodium greater than 145. A BUN/creatinine ratio greater than 20 was present in 68% of the subjects. Clinicians appear to be using the term dehydration synonymously with intravascular volume depletion. Even so, at least a third of the diagnoses of intravascular volume depletion in older adults were incorrect based on laboratory data.
CONCLUSIONS:
Physicians who diagnose dehydration during hospital admission may be relying more on physical signs than laboratory data. Little change in laboratory markers for hydration status occurs from the time of diagnosis to hospital discharge, suggesting that the clinical diagnosis does not affect fluid management. The data suggest a need for improvement in the differential diagnosis and management of volume changes in older persons.SB IM.
Le diagnostic clinique de déshydratation reste souvent difficile.
Sur le plan biologique, les critères de diagnostic de déshydratation reconnus (critères identiques à ceux présentés en réf 3) sont les suivants : 1/ déshydratation : osmolarité sérique > 295 milliosmols / 2/ diminution du volume intravasculaire : rapport Urée Nitrogène Sanguin (UNS) / créatine > 20 ou sodium sérique > 145 milligrammes par décilitre / 3/ hypovolémie : osmolarité sérique > 295 et rapport UNS/créatinine >20.
Ce travail montre que les cliniciens utilisent préférentiellement les signes physiques pour diagnostiquer la déshydratation au détriment des données biologiques. La confrontation avec les données de la biologie montre par ailleurs qu’ils ont tendance à parler de déshydratation même lorsque les paramètres biologiques sont en faveur d’une diminution du volume intravasculaire. Il semble actuellement nécessaire de développer des études qui permettront d’améliorer le diagnostic et la prise en charge de la déshydratation chez les personnes âgées.
3476 - Assessment of teeth as biomarkers for skeletal fluoride exposure.
Skeletal fluorosis and dental fluorosis are diseases related to fluoride (F) ingestion. Bone is the largest storage site of F in our body. Therefore, bone F concentrations are considered biomarkers for total F body burden (exposure). However, difficult accessibility limits its use as a biomarker. Thus, a more accessible tissue should be considered and analyzed as a biomarker for total F body burden. The objective of this study, which was divided into two parts, was to evaluate teeth as a biomarker for skeletal F exposure. In part 1 of the study, 70 mice of three different strains (SWR/J, A/J and 129P3/J) were exposed to different levels of water fluoridation (0, 25, 50 and 100 ppm). Bone (femora and vertebrae) and teeth from these mice were then analyzed for F concentration using Instrumental Neutron Activation Analysis (INAA). In part 2 of the study, human teeth (enamel and dentin) and bone from 30 study subjects were collected and analyzed for F concentration using INAA. Study subjects lived in areas with optimum levels of water fluoridation (0.7 and 1 ppm) and underwent therapeutic extraction of their unerupted third molars. The values of bone and teeth F concentration were correlated for parts 1 and 2 of this study. The results showed that in the animal model, where animals were exposed to a wide range of F in their drinking water, tooth [F] correlated with bone [F]. However, no correlation was seen between bone and enamel F concentrations or between bone and dentin F concentrations in the human samples. Therefore, teeth are not good biomarkers for skeletal F exposure in humans when exposure is confined to optimum levels of F in the drinking water.
L'os est le sigle le plus important de stockage pour le fluor dans notre corps, par conséquent, la concentration osseuse du fluor peut être considérée comme un bio-marqueur pour l'exposition totale du corps au fluor. Toutefois, l'accessibilité est difficile, limite, son usage comme bio-marqueur. Alors un tissu plus accessible peut être considéré et analysé comme un bio-marqueur pour la charge totale en fluor.
L'objectif de ce travail qui était divisé en deux parties était d'évaluer la dent comme un marqueur pour l'exposition au fluor du squelette. Dans la première partie de l'étude, 70 souris de 3 souches différentes ont été exposées à des taux différents de fluorisation de l'eau : 0,25/ 50 et 100 ppm. L'os fémoral ou vertèbre, et la dent de ces souris ont été analysés pour leur concentration en fluor en utilisant le système le système INAA (Instrumental Neutron Activation Analysis). Dans la deuxième partie de cette étude, la dent humaine, émail et dentine et les os de 30 autres sujets ont été collectés et analysés pour leur concentration en fluor en utilisant la même méthode.
Les sujets étudiés vivaient dans des contrées avec les taux optimums de fluorisation de l'eau : 0,7 à 1 ppm et les thérapeutiques d'extraction éventuelles des dents ont été utilisées après la 3ème molaire. Les valeurs de concentration en fluor de l'os et de la dent, ont été corrélées pour la première partie et la deuxième partie de l'étude.
Les résultats montraient que, chez l'animal comme modèle, lorsque ceux-ci ont été exposé à une grande variété de concentration de fluor dans leur eau de boisson, le fluor des dents était en corrélation avec le fluor de l'os. Cependant, il n'y avait pas de corrélation entre l'os et l'émail, ni entre la dentine et l'os, ceci chez les êtres humains. Par conséquent, la dent ne peut pas être considérée comme un bon bio-marqueur de l'exposition du squelette humain au fluor.
Intérêt : Ne pas croire que l'état dentaire et la fluorose sont des témoins de l'état du squelette.3477 - Bioavailability of fluoride in drinking water: a human experimental study.
It has been suggested that systemic fluoride absorption from drinking water may be influenced by the type of fluoride compound in the water and by water hardness. Using a human double-blind cross-over trial, we conducted this study to measure c(max), T(max), and Area Under the Curve (AUC) for plasma F concentration against time, following the ingestion of naturally fluoridated hard and soft waters, artificially fluoridated hard and soft waters, and a reference water. Mean AUC over 0 to 8 hours was 1330, 1440, 1679, 1566, and 1328 ng F.min.mL(-1) for naturally fluoridated soft, naturally fluoridated hard, artificially fluoridated soft, artificially fluoridated hard, and reference waters, respectively, with no statistically significant differences among waters for AUC, c(max), or T(max). Any differences in fluoride bioavailability between drinking waters in which fluoride is present naturally or added artificially, or the waters are hard or soft, were small compared with large within- and between-subject variations in F absorption. Abbreviations used: F, fluoride/ AUC, Area under the Curve for plasma F concentration against time/ AUC(0-3), Area under the Curve for plasma F concentration against time for 0 to 3 hours following water ingestion/ AUC(0-8), Area under the Curve for plasma F concentration against time for 0 to 8 hours following water ingestion/ c(max), maximum plasma F concentration corrected for baseline plasma F and dose (i.e., F concentration of individual waters)/ T(max), time of c(max).
3478 - Body composition measurement in severe obesity.
PURPOSE OF REVIEW: Severe obesity is accompanied by large increases in fat mass and alterations in the composition of fat free mass, in particular total body water and its extracellular compartment. The physical size limitations imposed by severe obesity, and variations in body composition from that of normal weight, pose tremendous challenges to the measurement of body composition. This review focuses on some of the methodological and practical issues associated with the use of common body composition methods, and identifies available published information on feasible methods for use in the severely obese. RECENT FINDINGS: There is little published research regarding what body composition methods can be used with confidence in the severely obese populations. A simple three-compartment model combining measurements of body density by air displacement plethysmography and total body water by bio-electrical impedance can provide measurements of percentage body fat in the severely obese that are comparable with a traditional, highly technical three-compartment model requiring facilities such as isotope ratio mass spectrometry along with a substantial technical expertise. SUMMARY: This review highlights some of the basic challenges faced by researchers and clinicians when conducting body composition assessments in severely obese patients. A simple three-compartment model that is accurate and easy to perform appears to be promising for use in this population. Further research is needed, however, on this and other feasible methods of body composition assessment in a diverse group of severely obese people.
3479 - Bone calcium turnover during pregnancy and lactation in women with low calcium diets is associated with calcium intake and circulating insulin-like growth factor 1 concentrations.
BACKGROUND: Few data exist on longitudinal changes in bone calcium turnover rates across pregnancy and lactation. OBJECTIVE: Our aim was to characterize calcium kinetic variables and predictors of these changes across pregnancy and early lactation in women with low calcium intakes. DESIGN: Stable calcium isotopes were administered to 10 Brazilian women during early pregnancy (EP/ weeks 10-12 of gestation), late pregnancy (LP/ weeks 34-36 of gestation), and early lactation (EL/ 7-8 wk postpartum). Multicompartmental modeling was used to assess the rates of bone calcium turnover in relation to calcium intakes and circulating concentrations of parathyroid hormone (PTH), insulin-like growth factor 1, and 1,25-dihydroxyvitamin D. RESULTS: Rates of bone calcium deposition increased significantly from EP to LP (P = 0.001) and were significantly associated with serum PTH during LP (P < or = 0.01). Rates of bone calcium resorption were also higher during LP and EL than during EP (P < or = 0.01) and were associated with both PTH (P < or = 0.01) and IGF-1 (P < or = 0.05) during LP but not during EL. Net balance in bone calcium turnover was positively associated with dietary calcium during EP (P < or = 0.01), LP (P < or = 0.01), and EL (P < or = 0.01). The mean (+/-SD) calcium intake was 463 +/- 182 mg/d and, in combination with insulin-like growth factor 1, explained 68-94% of the variability in net bone calcium balance during pregnancy and lactation. CONCLUSIONS: Net deficits in bone calcium balance occurred during pregnancy and lactation. Increased dietary calcium intake was associated with improved calcium balance/ therefore, greater calcium intakes may minimize bone loss across pregnancy and lactation in women with habitual intakes of <500 mg calcium/d.
Cette étude originale par sa méthodologie permet d’illustrer la nécessité de plus de deux apports par jour de produits lactés durant la grossesse et la lactation. Ceci rejoint les recommandations françaises.3480 - Calcium and dairy intakes in relation to long-term weight gain in US men.
BACKGROUND: The role of calcium in the maintenance of body weight remains controversial. OBJECTIVE: We investigated the association between calcium and dairy intakes and 12-y weight change in US men. DESIGN: This study was conducted with the use of data from the Health Professionals Follow-up Study, a prospective cohort of men aged 40-75 y in 1986. Data on lifestyle factors and diet were updated biennially with self-administered questionnaires. The participants reported their body weight in 1986 and in 1998. The outcome in our study was 12-y weight change. We used multivariate linear regression to examine how baseline calcium intake (n = 23,504) and change in calcium intake (n = 19,615) were associated with weight change. Because dairy foods are the predominant source of calcium in the diet, we also evaluated a similar association with dairy intake. RESULTS: In a multivariate analysis with adjustment for potential confounders, baseline or change in intake of total calcium was not significantly associated with weight change. In addition, we did not find any association with dietary, dairy, or supplemental calcium intake when evaluated separately. The men with the largest increase in total dairy intake gained slightly more weight than did the men who decreased intake the most (3.14 compared with 2.57 kg/ P for trend = 0.001). This association was primarily due to an increase in high-fat dairy intake. Low-fat dairy intake was not significantly associated with weight change. CONCLUSION: Our data do not support the hypothesis that an increase in calcium intake or dairy consumption is associated with lower long-term weight gain in men.
La relation entre apport de calcium ou produits laitiers et modification du poids corporel a été étudiée sur une période de 12 ans chez des hommes de 40 à 70 ans dans le cadre de la grande enquête prospective dite des professionnels de santé aux Etats-Unis (environ 20 000 participants). Les consommations étaient évaluées par questionnaire. Après une analyse statistique adaptée et ajustement pour les variables confondantes, aucune association n’a été constatée entre les changements de poids sur 12 ans et les apports de calcium total, du calcium du lait ou du calcium de supplément. Au contraire, des apports élevés de produits laitiers totaux, mais pas de produits allégés en matière grasse, ont conduit à une très légère augmentation de poids.
Commentaire : cette étude ne confirme pas l’hypothèse avancée par quelques auteurs d’une diminution du gain de poids associée à un apport plus élevé de calcium ou de produits laitiers.
3481 - Colon cancer mortality and total hardness levels in Taiwan''s drinking water.
The possible association between the risk of colon cancer and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible colon cancer deaths (1,714 cases) of Taiwan residents from 1989 through 1993 were compared with deaths from other causes (1,714 controls) and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan have been collected from Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and the controls were pair matched to the cases by sex, year of birth, and year of death. The results show a significant negative relationship between drinking water hardness and colon cancer mortality. Odds ratio and 95% confidence intervals were 1.22 (1.04-1. 43) and 1.46 (1.22-1.75), respectively, for exposure to moderately hard water and soft water compared with the use of hard water. Trend analyses showed an increasing odds ratio for colon cancer with decreasing levels of hardness in drinking water. This is an important finding for the Taiwan water industry and human health.
Ce travail, conduit à Taiwan, met en évidence une relation inverse significative entre la dureté de l’eau de consommation courante et la mortalité par cancer du colon.3482 - Magnesium and deaths ascribed to ischaemic heart disease in South Africa. A preliminary report.
The incidence of death from ischaemic heart disease (IHD) and acute cardiac arrhythmias is increased in some regions where magnesium levels are reduced in soil and water. Magnesium levels in the drinking water of twelve South African magisterial districts have been evaluated together with corrected statistics for deaths apparently due to IHD in White males from the same districts. A significant negative correlation was found between the incidence of deaths ascribed to IHD and the magnesium content of drinking water. Future, prospective, multivariate studies are required to elucidate whether magnesium scarcity in a geological environment is a major coronary risk factor.
Observation d'une corrélation négative entre la mortalité par ischémie cardiaque et la teneur de l'eau en Mg dans 12 localités d'Afrique du Sud.3483 - Dietary calcium intake among patients with urinary calculi.
Diet plays an important role in the formation and growth of kidney stones, and calcium intake below recommended dietary allowances may expose patients to a higher risk of recurrence. This study evaluated calcium intake and the dietary profile of 37 outpatients with renal lithiasis and 45 control subjects were age and sex matched. Dietary calcium, assessed by four-day dietary records, was significantly lower for patients with urinary calculi. When records for weekdays and Sunday were analyzed separately, a significantly lower calcium intake was again observed for patients with lithiasis both on weekdays and on Sundays. Adjustments to body mass index (BMI), income, age, and sex revealed a lower calcium intake for patients with lithiasis in all dietary records (P<0.02), which may be explained by the fact that physicians and nutritionists still recommend these patients reduce calcium intake. As this may be one more risk factor for recurrence, recommendations made by health professionals should be reviewed.
Cette étude attire l’attention sur un point important concernant le traitement préventif des récidives chez les sujets lithiasiques, à savoir l’apport alimentaire en calcium recommandé à ces patients. Les auteurs ont comparé, par questionnaire diététique, les apports alimentaires de 37 patients suivis pour lithiase rénale calcique et de 45 sujets non-lithiasiques appariés pour l’âge et le sexe. L’apport alimentaire quotidien en calcium, déterminé sur 4 jours, s’est révélé significativement plus faible chez les lithiasiques que chez les témoins et ce, aussi bien pendant les jours de semaine que pendant les dimanches. Cette constatation montre que la plupart des médecins et des nutritionnistes continuent à prescrire une restriction des apports calciques chez les sujets lithiasiques, en dépit des travaux récents qui ont montré de manière concordante les inconvénients d’un faible apport calcique alimentaire chez ces patients : augmentation de l’absorption intestinale de l’oxalate, risque de déminéralisation osseuse, plus grande fréquence de lithiase.3484 - The role of dietary calcium in bone health.
Approximately 99% of body Ca is found in bone, where it serves a key structural role as a component of hydroxyapatite. Dietary requirements for Ca are determined by the needs for bone development and maintenance, which vary throughout the life stage, with greater needs during the periods of rapid growth in childhood and adolescence, during pregnancy and lactation, and in later life. There is considerable disagreement between expert groups on the daily Ca intake levels that should be recommended, reflecting the uncertainty in the data for establishing Ca requirements. Inadequate dietary Ca in early life impairs bone development, and Ca supplementation of the usual diet for periods of (less-than or equal to)3 years has been shown to enhance bone mineral status in children and adolescents. However, it is unclear whether this benefit is long term, leading to the optimisation of peak bone mass in early adulthood. In later years inadequate dietary Ca accelerates bone loss and may contribute to osteoporosis. Ca supplementation of the usual diet in post-menopausal women and older men has been shown to reduce the rate of loss of bone mineral density at a number of sites over periods of 1-2 years. However, the extent to which this outcome reduces fracture risk needs to be determined. Even allowing for disagreements on recommended intakes, evidence indicates that dietary Ca intake is inadequate for maintenance of bone health in a substantial proportion of some population groups, particularly adolescent girls and older women.
Courte revue de synthèse sur les relations entre apport calcique alimentaire et ostéoporose, rappelant les principales fonctions du calcium, la structure et les fonctions de l’os, la définition et les causes de l’ostéoporose et des fractures osseuses et les difficultés d’évaluation des besoins nutritionnels conduisant aux désaccords entre les « normes » des divers pays. Les principales études (mais pas toutes) démontrant un effet favorable d’un supplément de calcium, soit par un sel minéral, soit par le lait, sur la densité osseuse et sur l’incidence des fractures, ont été résumées et analysées. Compte tenu des apports trop faibles en calcium chez les adolescentes, les femmes ménopausées et les personnes âgées, quelles que soient les recommandations adoptées, l’action bénéfique d’un supplément calcique sur l’os par augmentation de l’accrétion ou par diminution de la résorption est bien établie. En revanche, la « durabilité » de l’effet du pic de capital osseux acquis chez le jeune adulte doit être confirmée par de nouvelles études longitudinales.3485 - Dietary magnesium intake in relation to plasma insulin levels and risk of type 2 diabetes in women.
OBJECTIVE:
Higher intake of magnesium appears to improve glucose and insulin homeostasis/ however, there are sparse prospective data on the association between magnesium intake and incidence of type 2 diabetes. RESEARCH DESIGN AND
METHOD:
In the Women''s Health Study, a cohort of 39,345 U.S. women aged >/=45 years with no previous history of cardiovascular disease, cancer, or type 2 diabetes completed validated semiquantitative food frequency questionnaires in 1993 and were followed for an average of 6 years. We used Cox proportional hazard models to estimate multivariate relative risks (RRs) of type 2 diabetes across quintiles of magnesium intake compared with the lowest quintile. In a sample of 349 apparently healthy women from this study, we measured plasma fasting insulin levels to examine their relation to magnesium intake.
RESULTS:
During 222,523 person-years of follow-up, we documented 918 confirmed incident cases of type 2 diabetes. There was a significant inverse association between magnesium intake and risk of type 2 diabetes, independent of age and BMI (P = 0.007 for trend). After further adjustment for physical activity, alcohol intake, smoking, family history of diabetes, and total calorie intake, the multivariate-adjusted RRs of diabetes from the lowest to highest quintiles of magnesium intake were attenuated at 1.0, 1.06, 0.81, 0.86, and 0.89 (P = 0.05 for trend). Among women with BMI >/=25 kg/m2, the inverse trend was significant/ multivariate-adjusted RRs were 1.0, 0.96, 0.76, 0.84, and 0.78 (P = 0.02 for trend). Multivariate-adjusted geometric mean insulin levels for overweight women in the lowest quartile of magnesium intake was 53.5 compared with 41.5 pmol/l among those at the highest quartile (P = 0.03 for trend).
CONCLUSION:
These findings support a protective role of higher intake of magnesium in reducing the risk of developing type 2 diabetes, especially in overweight women.SB IM.
Ce travail étudie la relation entre consommation de magnésium et risque d’apparition du diabète de type 2. Il porte sur le suivi, pendant 6 ans, de 39345 femmes (américaines) âgées de 45 ans et plus, initialement indemnes de toute pathologie cardiovasculaire, de cancer ou de diabète de type 2. Les résultats montrent une corrélation inverse entre la consommation de magnésium et le risque d’apparition d’un diabète de type 2. Il est conclu qu’une consommation plus élevée de Mg pourrait avoir un effet protecteur vis à vis du risque diabétique, surtout chez les femmes en surcharge pondérale.3486 - Calcium- and vitamin D3-fortified milk reduces bone loss at clinically relevant skeletal sites in older men: a 2-year randomized controlled trial.
In this 2-year randomized controlled study of 167 men >50 years of age, supplementation with calcium-vitamin D3-fortified milk providing an additional 1000 mg of calcium and 800 IU of vitamin D3 per day was effective for suppressing PTH and stopping or slowing bone loss at several clinically important skeletal sites at risk for fracture. INTRODUCTION: Low dietary calcium and inadequate vitamin D stores have long been implicated in age-related bone loss and osteoporosis. The aim of this study was to assess the effects of calcium and vitamin D3 fortified milk on BMD in community living men >50 years of age. MATERIALS AND METHODS: This was a 2-year randomized controlled study in which 167 men (mean age +/- SD, 61.9 +/- 7.7 years) were assigned to receive either 400 ml/day of reduced fat ( approximately 1%) ultra-high temperature (UHT) milk containing 1000 mg of calcium plus 800 IU of vitamin D3 or to a control group receiving no additional milk. Primary endpoints were changes in BMD, serum 25(OH)D, and PTH. RESULTS: One hundred forty-nine men completed the study. Baseline characteristics between the groups were not different/ mean dietary calcium and serum 25(OH)D levels were 941 +/- 387 mg/day and 77 +/- 23 nM, respectively. After 2 years, the mean percent change in BMD was 0.9-1.6% less in the milk supplementation compared with control group at the femoral neck, total hip, and ultradistal radius (range, p < 0.08 to p < 0.001 after adjusting for covariates). There was a greater increase in lumbar spine BMD in the milk supplementation group after 12 and 18 months (0.8-1.0%, p < or = 0.05), but the between-group difference was not significant after 2 years (0.7%/ 95% CI, -0.3, 1.7). Serum 25(OH)D increased and PTH decreased in the milk supplementation relative to control group after the first year (31% and -18%, respectively/ both p < 0.001), and these differences remained after 2 years. Body weight remained unchanged in both groups at the completion of the study. CONCLUSIONS: Supplementing the diet of men >50 years of age with reduced-fat calcium- and vitamin D3-enriched milk may represent a simple, nutritionally sound and cost-effective strategy to reduce age-related bone loss at several skeletal sites at risk for fracture in the elderly.
Etude d’intervention contrôlée randomisée sur 149 hommes d’âge moyen de 62 ans recevant pendant 2 années, en plus d’un apport moyen de 940 mg de calcium par jour, un supplément de 400 g par jour d’un lait pauvre en lipides et enrichi en calcium et en vitamine D3, soit environ 1000 mg de Ca et 800 UI de vitamine D3 en plus. A la fin de l’étude, la densité minérale osseuse au niveau de la tête du fémur, de la hanche et du radius distal était plus faible de 0,9-1,6 % dans le groupe ne recevant pas de supplément. La différence dans le même sens était de 0,8-1,0 % pour les vertèbres lombaires après 18 mois mais n’était plus significative après 2 ans. La teneur en 25 (OH) D sérique a augmenté de 31 % au bout d’une année et celle en PTH a diminué de 18 %, ces différences étant maintenues après 2 ans.
Commentaire : il s’agit d’une démonstration supplémentaire de l’effet favorable d’un apport élevé de calcium et de vitamine D sur la masse minérale osseuse a près 50 ans, cette action se produisant probablement par l’intermédiaire d’une diminution de l’activité de la PTH et donc de la résorption osseuse. De telles études sont nombreuses chez la femme après la ménopause, mais rares chez l’homme. Cependant, pour obtenir un tel effet sur l’os, des apports aussi élevés de calcium (près de 2 g par jour !) ne sont évidemment pas nécessaires. Il suffirait de s’approcher des ANC de 1200 mg par jour !
3487 - Food mixture or ingredient sources for dietary calcium: shifts in food group contributions using four grouping protocols.
Identifying dietary sources of nutrients by assigning survey foods to food groups can under- or overestimate the contribution a group makes to the intake of specific nutrients. Using calcium and food intakes from USDA''s 1994-1996, 1998 Continuing Survey of Food Intakes by Individuals, the authors determined the proportion of dietary calcium from the dairy, grains, meats, fruits, and vegetables groups using four grouping protocols. Calcium contributions from milk and cheese were higher as more ingredient sources and fewer survey food items were represented in the dairy group. Milk, cheese, and yoghurt reported as separate survey food items contributed 42% of total calcium intake. An additional 21% of dietary calcium came from dairy ingredients in mixed foods such as macaroni and cheese, pizza, sandwiches, and desserts. The remaining dietary calcium sources were single grains (16%)/ vegetable (7%)/ meat, poultry, and fish (5%)/ fruit (3%)/ and miscellaneous foods (7%). Data quantifying the nutrient contributions from dairy ingredients could affect dietary guidance messages or research using dairy foods as variables.
Etude critique des méthodes d’évaluation de la consommation de calcium selon la subdivision plus ou moins fine des groupes d’aliments et plats composés en aliments simples ou matières premières. Evaluation faite à partir des données obtenues de 1994 à 1998 par l’USDA (Continuing Survey of Food Intakes by Individuals). Quatre protocoles d’évaluation ont été comparés. Ainsi, l’apport calculé de calcium laitier est plus élevé lorsque l’on prend en compte plus d’ingrédients et moins de produits individuels. Le lait, les fromages et les yaourts apportent ensemble 42 % du calcium total consommé, auquel s’ajoutent 21 % provenant des produits laitiers incorporés aux plats préparés (pâtes, pizza, sandwiches, desserts). Les céréales et autres graines représentent 16 % du calcium total, les légumes 7 %, les viandes et poissons 5 %, les fruits 3 % et les divers (dont l’eau et autres boissons) 7 %. Commentaire : cette nouvelle évaluation des apports calciques aux Etats-Unis correspond bien aux estimations françaises pour les produits laitiers (63 % au total) mais est plus élevée pour les céréales (en plus grande partie enrichies en calcium) et plus faible pour les légumes (sans doute plus consommés en France).3488 - Dietary magnesium intake and the future risk of coronary heart disease (The Honolulu Heart Program).
Magnesium (Mg) deficiency is believed to have adverse cardiovascular consequences that are broad and complex, although an association between dietary Mg intake and the risk of coronary heart disease (CHD) has not been clearly identified. The purpose of this study is to examine the relation between dietary Mg intake and future risk of CHD. Reported findings are based on dietary Mg intake in 7,172 men in the Honolulu Heart Program. Intake of Mg was recorded at baseline examinations that took place from 1965 to 1968 when the men were aged 45 to 68 years. In 30 years of follow-up, 1,431 incident cases of CHD were identified. Within 15 years after dietary assessment, the age-adjusted incidence decreased significantly from 7.3 to 4.0 per 1,000 person-years in the lowest (50.3 to 186 mg/day) versus highest (340 to 1,183 mg/day) quintiles of Mg intake (p < 0.001). When adjustments were made for age and other nutrients (singly or combined), there was a 1.7- to 2.1-fold excess in the risk of CHD in the lowest versus highest quintiles (p < 0.001). The excess risk ranged from 1.5- to 1.8-fold after further adjustment for other cardiovascular risk factors (p < 0.05). Associations between dietary Mg and coronary events occurring after 15 years of follow-up were modest. We conclude that the intake of dietary Mg is associated with a reduced risk of CHD. Whether increases in dietary Mg intake can alter the future risk of disease warrants further study.
3489 - Dairy and dairy-related nutrient intake during middle childhood.
OBJECTIVE: To characterize patterns of dairy intake among girls in middle childhood. DESIGN: Longitudinal data were used to characterize girls' patterns of dairy intake at age 5, 7, 9, and 11 years. SUBJECTS: Participants were 151 girls from predominately middle-class and exclusively non-Hispanic white families living in central Pennsylvania. STATISTICAL ANALYSES: Intakes of dairy, energy, macronutrients, vitamin D, calcium, and phosphorus were assessed using three 24-hour dietary recalls in 151 non-Hispanic white girls at age 5, 7, 9, and 11 years. Analyses of changes over time were conducted using repeated measures analysis of variance. McNemar's chi(2) test was used to analyze change in percentage of dairy consumers over time. RESULTS: From age 5 to 11 years, girls' total dairy intake remained stable. Total milk consumption declined, due to a decline in intake of milk as a beverage, while intakes of cheese and dairy desserts increased. Much of the decline in milk intake from age 5 to 11 years, especially for milk as a beverage, was due to a reduction in the percentage of girls consuming milk as a beverage, not simply due to a decline in the servings of milk as a beverage consumed by consumers. On average, girls met vitamin D recommendations over time/ however, by age 9 and 11 years girls failed to meet calcium and phosphorus recommendations. CONCLUSIONS: Although girls' dairy intake was stable over time, at age 7, 9, and 11 years girls did not meet the recommended three servings per day, leading to suboptimal intakes of calcium and phosphorus at age 9 and 11 years. Increasing milk intake among all children should continue to be a major focus of interventions.
Cette enquête sur les profils de consommation de produits laitiers a été effectuée en Pennsylvanie sur 151 filles de 5 à 11 ans, de race blanche non hispanique. Les apports alimentaires ont été évalués à l’aide de trois rappels de 24 h. La consommation de produits laitiers reste stable de 5 à 11 ans, mais celle de lait liquide diminue tandis que celle de fromages et desserts lactés augmente. A partir de 7 ans, les trois produits laitiers par jour recommandés ne sont pas consommés, ce qui ne permet pas d’atteindre les ANC en calcium et phosphore.
Commentaire : la consommation de produits laitiers par les filles de 7 à 11 ans dans cet Etat américain ne permet pas d’atteindre les apports conseillés en calcium et en phosphore. Cela ne semble pas être le cas en France pour le calcium, et encore moins pour le phosphore.
3490 - Dairy foods, dietary calcium and obesity: A short review of the evidence.
The possible association between dairy products consumption and body weight regulation has been the subject of several recent publications. The interest in this issue arose after biologically plausible mechanisms for this association were identified: most of these suggested a key role for calcium intake from dairy products, although calcium-independent mechanisms have also been proposed. Data from cross-sectional epidemiological studies support the hypothesis that a dairy food-rich diet is associated with lower fat accumulation in adults and children/ however, prospective studies and randomised controlled intervention trials have yielded inconsistent results. Different reasons could explain these findings that regard the evaluation of either the exposure (i.e. the methodological problems in the assessment of dietary intake of nutrients over a long time) and the outcome (i.e. multiple factors involved in the regulation of body weight). Moreover, it could also be hypothesised that high consumption of dairy foods would be a marker of healthier lifestyles, or that nutritional differences exist within dairy products. Available data do not unequivocally support the hypothesis that a causal relationship exists between high dairy food intake -and/or high dietary calcium intake- and lower fat mass deposition. However, research in this field should aim to define the health impact of dairy foods even beyond obesity.
Cette brève revue sur les relations éventuelles entre consommation de produits laitiers ou de calcium et l’obésité constitue une bonne réflexion et une mise au point opportune sur ce sujet controversé. Même si les mécanismes d’action proposés pour expliquer cette association sont plausibles, il semble difficile de conclure. Des données issues d’études épidémiologiques supportent cette hypothèse d’une relation inverse entre régime riche en produits laitiers et accumulation de tissu adipeux chez des adultes et des enfants, mais les études prospectives ou d’intervention contrôlées ne confirment pas toutes cette relation. Ce désaccord entre études provient probablement de l’imprécision des méthodes de l’épidémiologie d’observation et de la non prise en compte d’autres facteurs.
Commentaire : cette mise au point confirme à nouveau l’absence de relation causale entre apports de produits laitiers ou de calcium et incidence de l’obésité et ne soutient pas les hypothèses mécanistiques avancées par quelques auteurs.
3491 - Dietary interventions on blood pressure: the Dietary Approaches to Stop Hypertension (DASH) trials.
The Dietary Approaches to Stop Hypertension (DASH) diet may improve health in new ways other than the obviously beneficial cardiovascular effects. The DASH diet may also reduce the risk of some cancers, and the calcium in the dairy products would help to lower the risk of osteoporosis. One of the key things that has been promoted in the DASH studies is that it is made up of regular foods that are available at most grocery stores. Additionally, the DASH diet is consistent with many of the recommendations made by organizations in the United States: the Dietary Guidelines for Americans, the National Cholesterol Education Program's Step 2 Diet, and the National Cancer Institute.
3492 - Effect of micronutrient supplementation on health and nutritional status of schoolchildren in India.
Four papers are presented entitled: 'Effect of micronutrient supplementation on health and nutritional status of schoolchildren: growth and morbidity,' by K.V. Rameshwar Sarma, P. Udaykumar, N. Balakrishna, K. Vijayaraghavan and B. Sivakumar/ 'Effect of micronutrient supplementation on health and nutritional status of schoolchildren: biochemical status,' by B. Sivakumar, K.M. Nair, D. Sreeramulu, P. Suryanarayana, P. Ravinder, V. Shatrugna, P.A. Kumar, M. Raghunath, V.V. Rao, N. Balakrishna, P.U. Kumar and N. Raghuramulu/ 'Effect of micronutrient supplementation on health and nutritional status of schoolchildren: mental function,' by S. Vazir, B. Nagalla, V. Thangiah, V. Kamasamudram and S. Bhattiprolu/ and 'Effect of micronutrient supplementation on health and nutritional status of schoolchildren: bone health and body composition', by V. Shatrugna, N. Balakrishna and K. Krishnaswamy. Studies were conducted to evaluate the effect of a beverage fortified with micronutrients on growth and morbidity/ biochemical status of important micronutrients/ mental function/ and body composition, bone area, bone mineral content and bone mineral density, in apparently healthy schoolchildren. The studies were carried out in India as double-blind, placebo-controlled, matched-pair, cluster, randomised trials on residential schoolchildren aged between 6 and 16 over a 14-month period. The results showed the fortified beverage was beneficial in promoting growth and reducing the duration of common illnesses/ had a positive effect on the nutrients that were found to be deficient at baseline evaluation/ significantly improved attention concentration, but not memory, intelligence or school achievement/ and increased tissue growth and skeletal shell.
4 documents sont présentés concernant des études réalisées aux Indes sur le rôle d'un supplément en micronutriments chez des enfants d'âge scolaire. Les résultats montrent un bénéfice sur la croissance, la durée des maladies communes de l'enfant, l'attention et la concentration. La supplémentation en micronutriment a un effet bénéfique sur la croissance et diminue la durée de maladies communes et améliore la scolarité des enfants.3493 - Fluoride concentration in saliva after consumption of a dinner meal prepared with fluoridated salt.
The aim was to determine the fluoride concentration in saliva after intake of a dinner meal prepared with fluoridated salt. The investigation had a randomized cross-over design, and 10 healthy adolescents with natural fluoride content (1.06 ppm) in their drinking water participated after informed consent. After a run-in week, the subjects were served a standardized dinner of spaghetti with minced meat sauce prepared with either fluoridated salt (test arm) or non-fluoridated salt (control arm). The fluoride concentration of the test salt was 250 ppm. Samples of stimulated whole saliva was collected at baseline, directly after eating (0 min) and then after 10, 30 and 180 min. After a 1-week wash-out period, the experimental procedure was repeated with the opposite salt. Fluoride concentration in saliva was measured with a fluoride-specific electrode and the post-ingestion levels were compared with baseline using repeated-measures ANOVA.The mean baseline concentrations were 10.9 and 8.0 microg/l in the test and control arms, respectively. Immediately after the intake, the mean fluoride values increased significantly to 81.6 microg/l in the test arm and to 31.5 microg/l in the control arm (p<0.05). The fluoride levels remained elevated (p<0.05) for 30 min after ingestion of the test meal but not following the control meal. In conclusion, consumption of a dinner meal prepared with fluoridated salt increased the salivary fluoride levels for about 30 min.
Evaluation de la quantité d'ions fluorures dans la salive après ingestion d'un repas préparé avec du sel fluoré sur une population d'adolescents bénéficiant déjà d'un apport optimal de fluor dans l'eau de boisson. La concentration de fluor dans la salive augmente avec un facteur de 8 pour le groupe ayant ingéré le repas préparé avec du sel fluoré alors que la concentration salivaire est multipliée par 4 lorsque le repas est préparé avec un sel normal. Cette concentration reste élevée pendant les 30 minutes qui suivent le repas.
Intérêt : Données intéressantes pour le calcul d'un bilan fluoré. Intéressant pour la banque de données.3494 - Dietary therapy in idiopathic nephrolithiasis
Like other diseases striking predominantly the affluent societies, idiopathic nephrolithiasis is increasing in rich countries and appears to be closely related to dietary habits. In this review we summarize the latest evidence about the efficacy of dietary treatment for idiopathic calcium and uric acid stones, dealing especially with its effect on the urinary stone risk factors, stone recurrences, and clinical limitations. After a short introduction on epidemiology and pathogenesis, we review the role of the most important foods and nutrients in stone formation and protection: water and other fluids, proteins, carbohydrates, fats, salt, milk and dairy products, fruits and vegetables, and vitamins. The final part of the paper will provide practical guidelines for pursuing an anti-lithogenic diet in idiopathic calcium and uric acid stones.
Dans cette revue générale, les auteurs soulignent l'importance de l'abord nutritionnel du traitement préventif de la lithiase calcique ou urique idiopathique. En particulier, ils soulignent l'importance fondamentale de la dilution des urines pour diminuer leur sursaturation en oxalate de calcium, sachant qu'elle ne diminue substantiellement que lorsque le volume des urines dépasse 2 litres par jour. Ce résultat ne peut être obtenu que par une augmentation de la consommation d'eau en quantité suffisante pour atteindre une diurèse d'au moins 2 litres par jour. Dans le cas de la lithiase calcique, il est recommandé de maintenir un apport calcique global d'environ 1 gramme par jour, fourni à la fois par le calcium contenu dans l'eau de boisson et par celui apporté par les produits laitiers.3495 - Growth, bone mass, and vitamin D status of Chinese adolescent girls 3 y after withdrawal of milk supplementation.
BACKGROUND: A 2-y school milk intervention trial showed that 330 mL of a dietary milk supplement (fortified with calcium alone or with both calcium and vitamin D) enhanced the growth and bone mineral accretion of Chinese girls aged 10 y at baseline. Girls who received milk fortified with both calcium and vitamin D also had better vitamin D status than did girls who received nothing or girls who received milk fortified only with calcium. OBJECTIVE: The aim was to evaluate whether these effects were sustained 3 y after supplement withdrawal. DESIGN: Anthropometric measures and dietary intake were reassessed in 501 of the 698 girls whose data had been studied at the end of the intervention. As in the intervention phase, total-body bone mineral content and bone mineral density and serum 25-hydroxyvitamin D concentrations were measured in half of these subjects. RESULTS: At follow-up, 99% of girls had reached menarche, at a mean (+/-SD) menarcheal age of 12.1 +/- 1.1 y. No significant differences in the timing of menarche were observed between the 3 groups (P = 0.6). No significant differences in the changes of total-body bone mineral content and bone mineral density since baseline were observed between the groups. The group receiving calcium-fortified milk had significantly greater gains in sitting height (0.9 +/- 0.3%/ P = 0.02) than did the control group. The group that received calcium- and vitamin D-fortified milk had 17.1 +/- 6.7% lower serum 25-hydroxyvitamin D concentrations than did the control group (P = 0.04), but the difference was attenuated by additional adjustment for physical activity level (14.2 +/- 6.7%/ P = 0.08). CONCLUSION: Milk supplementation during early puberty does not have long-lasting effects on bone mineral accretion.
3496 - Hypercalciuria
The frequency of hypercalciuria is increasing in western countries with an incidence of nephrolithiasis which can reach 13%. Hypercalciuria appears as an alteration of the calcium transport system (kidney, bowel, bone) which is regulated by calcitriol and parathormone. The aim of this review was to screen etiologies of hypercalciuria taking into account recent genetic advances (calcium epithelial channel and calcium sensing receptor). Hypercalciuria may be favored by nutritional causes (diet rich in calcium, sodium, carbohydrates, proteins, poor in phosphates and potassium). It may also be related to an increase in calcium absorption (vitamin D excess, primary hyperparathyroidism, sarcoidosis, lymphoma, estrogens, and certain genetic causes), an increase in osteoresorption (bone metastasis, myeloma, Paget, hyperthyroidism, immobilization, hypercortisolism and corticosteroid therapy), or a decrease of kidney tubular resorption (diuretics, Cacci and Ricci, acromegally, Bartter, familial dominant hypocalcemia, Fanconi, Dent, familial hypomagnesemia-hypercalciuria syndrome, type 1 distal tubular acidosis, pseudohypoaldosteronism, diabetes). If no cause is identified, persistence of hypercalciuria after instituting a correct diet is defined as idiopathic hypercalciuria. Treatment of the cause is essential in secondary hypercalciuria, in addition to diet (low sodium intake, normocalcic diet, hydration), associated with thiazide diuretics and biphosphonates if necessary.
Cette revue générale complète et bien documentée met l'accent sur l'importance de l'hypercalciurie à l'origine de la lithiase rénale, sur son mécanisme et sur ses causes, à la lumière des progrès récents de la physiologie et de la génétique. En particulier, les causes nutritionnelles (notamment, un apport trop élevé de calcium, de sel, de sucres ou de protéines) et les causes endocriniennes ou systémiques (hyperparathyroidie primitive, sarcoidise, hyperthyroidie, hypercorticisme) et tumorales (métastases osseuses de tumeurs, lymphomes, myélome multiple, maladie de Paget), de même que les causes médicamenteuses (prise excessive de vitamine D, traitements corticoides) sont rappelées. Outre ces causes d'hypercalciurie secondaire déjà bien connues, cette revue a l'intérêt de mentionner les causes génétiques plus rares, mais qui demandent à être connues car elles correspondent à des pathologies sévères pouvant conduire à l'insuffisance rénale, qui peuvent désormais être reconnues grâce aux progrès de l'exploration fonctionnelle et de la génétique moléculaire. Ce sont, notamment, la maladie de Dent, l'hypomagnésémie familiale, le syndrome de Bartter, l'hypocalcémie familiale, les acidoses tubulaires distales primitives et le pseudo hypoaldostéronisme. Toutes ces hypercalciuries secondaires demandent un traitement adapté à leur cause. Toutefois, dans la plupart des cas, aucune cause ne peut être identifiée et l'on parle alors d'hypercalciurie idiopathique. Dans ce cas, le traitement repose sur un apport calcique normalisé (ni trop faible, ni trop élevé) soit 800 à 1000 mg de calcium par jour, associé à une modération de l'apport en protéines animales et en sel et à une diurèse d'au moins 2 litres par 24h par la prise abondante de boissons. Lorsque la concentration du calcium urinaire reste excessivement élevée malgré ces mesures, il peut être indiqué de leur associer la prise d'un diurétique thiazidique ou, parfois, de biphosphonates.3497 - Higher calcium urinary loss induced by a calcium sulphate-rich mineral water intake than by milk in young women.
It is well known that the intestinal availability of Ca from Ca-rich mineral waters is equivalent to that of milk Ca. However, the effect of associated anions on Ca urinary loss needs to be addressed. The aim of the current study was to compare, under ordinary conditions of consumption, milk and a SO(4)-rich mineral water as the Ca provider in a large number of subjects consuming the same quantity of Ca from the two sources in a crossover study lasting for an extended period. Thirty-seven healthy women completed a 12- week protocol, divided into four periods of 3 weeks (W). In the first (W1-3) and third (W6-9) periods, dietary Ca intake was restricted to 600 mg/d. In the second (W4-6) and final (W10-12) periods, either 400 ml/d medium-fat milk or 1 litre of a Ca- and SO(4)-rich mineral water, each providing about 480 mg Ca/d, was added to the diet in a random manner. Dietary evaluation, blood and urinary measures were performed during the last week (W6 and W12) of each Ca supplementation period. The urinary excretion of Ca was higher (0.5 mmol/d more) with water than with milk (P<0.001). An examination of all the dietary factors known to influence calciuria suggested that the acidogenic action of SO(4) was responsible for this increased calciuria. Thus, despite an equal Ca intake and assuming an unchanged intestinal absorption, these results suggest that Ca balance is better with milk consumption than with CaSO (4)-rich water.
3498 - Hypohydration impairs endurance exercise performance in temperate but not cold air.
This study compared the effects of hypohydration (HYP) on endurance exercise performance in temperate and cold air environments. On four occasions, six men and two women (age = 24 +/- 6 yr, height = 170 +/- 6 cm, weight = 72.9 +/- 11.1 kg, peak O2 consumption = 48 +/- 9 ml.kg(-1).min(-1)) were exposed to 3 h of passive heat stress (45 degrees C) in the early morning with [euhydration (EUH)] or without (HYP/ 3% body mass) fluid replacement. Later in the day, subjects sat in a cold (2 degrees C) or temperate (20 degrees C) environment with minimal clothing for 1 h before performing 30 min of cycle ergometry at 50% peak O2 consumption followed immediately by a 30-min performance time trial. Rectal and mean skin temperatures, heart rate, and ratings of perceived exertion measurements were made at regular intervals. Performance was assessed by the total amount of work (kJ) completed in the 30-min time trial. Skin temperature was significantly lower in the cold compared with the temperate trial, but there was no independent effect of hydration. Rectal temperature in both HYP trials was higher than EUH after 60 min of exercise, but the difference was only significant within the temperate trials (P < 0.05). Heart rate was significantly higher at 30 min within the temperate trial (HYP > EUH) and at 60 min within the cold trial (HYP > EUH) (P < 0.05). Ratings of perceived exertion increased over time with no differences among trials. Total work performed during the 30-min time trial was not influenced by environment but was less (P < 0.05) for HYP than EUH in the temperate trials. The corresponding change in performance (EUH-HYP) was greater for temperate (-8%) than for cold (-3%) (P < 0.05). These data demonstrate that 1) HYP impairs endurance exercise performance in temperate but not cold air but 2) cold stress per se does not.
3499 - Esophageal cancer mortality and total hardness levels in Taiwan''s drinking water.
The possible association between the risk of esophageal cancer and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible esophageal cancer deaths (2084 cases) of Taiwan residents from 1987 through 1996 were compared with deaths from other causes (2084 controls), and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan have been collected from the Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and the controls were pair-matched to the cases by sex, year of birth, and year of death. The results show that there is a 42% excess risk of mortality from esophageal cancer in relation to the use of soft water (adjusted odds ratio and 95% confidence intervals was 1.42 (1.22-1.66). This is an important finding for the Taiwan water industry and human health.
Ce travail, conduit à Taiwan, met en évidence un risque accru de 42% de la mortalité par cancer de l’œsophage (risque relatif de 1,42, CI : 1,22-1,66) parmi les utilisateurs d’eau peu minéralisée (eau très douce) comparativement aux utilisateurs d’eaux de dureté plus élevée.3500 - Hyponatremia and arginine vasopressin dysregulation: mechanisms, clinical consequences, and management
Hyponatremia, the most common electrolyte disorder, occurs frequently in older people and in hospitalized patients. Physiological changes of aging that interact with diseases and drugs commonly present in older people put this population at greater risk for hyponatremia. It can accompany central nervous system disorders, pulmonary and renal disease, cancer, congestive heart failure, and liver cirrhosis, as well as many commonly used drugs. Delayed recognition can lead to symptomatic hyponatremia with consequent cerebral edema and possibly irreversible neurological damage. Symptoms and signs of hyponatremia may be subtle or not attributed to hyponatremia. Most cases are of the euvolemic type, in which extracellular fluid volume is normal and is often due to the syndrome of inappropriate secretion of antidiuretic hormone. Hyponatremia can also occur in association with hypervolemia or hypovolemia. Common to all of these circumstances is increased secretion of arginine vasopressin (AVP). Understanding of the pathophysiological basis of hyponatremia and of brain compensatory mechanisms is critical to safe treatment. Fluid restriction or infusion of hypertonic saline can improve symptoms and normalize serum sodium levels but does not address excess AVP, which in most cases is the underlying cause of the disorder. A major new approach to treatment of hyponatremia is the development of aquaretics: AVP-receptor antagonists that provide a targeted therapeutic approach to correcting the many kinds of hyponatremia caused by excess AVP levels.
L'hyponatrémie est une pathologie fréquente chez la personne âgée, pouvant entraîner des complications sévères. Elle peut être liée à un syndrome de sécrétion inappropriée d'hormone antidiurétique (AVP) qui peut être traité par des antagonistes des récepteurs à l'AVP ou des drogues acquarétiques.3501 - Health implications of iron overload: the role of diet and genotype.
The relationship between high dietary iron intake, mutations of the HFE gene, and iron status, and their effects on human health are reviewed. Prolonged high dietary intakes of iron are unlikely to result in iron overload in the general population. Homozygotes for the C282Y mutation of the HFE gene have elevated body iron levels. Heterozygotes have normal iron stores but some may be at increased risk for cardiovascular disease. There is no convincing evidence that elevated iron status increases the risk of coronary heart disease or type 2 diabetes, but high iron intakes may increase the risk of colorectal cancer. The dietary levels of iron associated with health risks in different HFE genotypes must be determined.
Cette revue envisage les conséquences pour la santé du statut martial des sujets porteurs de mutation C2829 du gène HFE. Les sujets hétérozygotes ont un statut martial normal mais certains pourraient présenter un risque accrus de pathologie cardiovasculaire. Les sujets homozygotes ont des réserves ferriques accrues, avec une augmentation de risque de cancer colorectal.3502 - Impact of micronutrient dietary intake and status on intestinal zinc absorption in late middle-aged men: the ZENITH study.
BACKGROUND: Adjustments in intestinal absorption and losses of zinc (Zn) are thought to maintain Zn homeostasis when dietary intake levels are altered. Zn status may also influence efficiency of intestinal Zn absorption. OBJECTIVES: To determine the impact of dietary intake and status of some micronutrients on Zn absorption in late middle-aged men. DESIGN AND PARTICIPANTS: Dietary intake and status of Zn, Cu, Fe, vitamin A, C and fibre, and absorption of Zn were measured in 48 men, aged 58-68 y, confined to a metabolic unit and consuming a typical French diet. Dietary intake was estimated using 4-day food-intake records (including the weekend) and the GENI program. To assess Zn status, serum, erythrocyte, urine Zn levels and serum alkaline phosphatase activity were determined. Zn absorption was determined using the isotope double-labelling method. Zn stable isotopic ratios were measured in plasma samples collected before and 48 h after isotope administration using ICP/MS. RESULTS: Zn intake within the group of men varied from 5.7 to 20.5 mg/day and averaged 12.9 mg/day. Serum Zn level varied from 10 to 18 micromol/l and averaged 12.9 micromol/l. Zn absorption varied from 12 to 46% and averaged 29.7%. Zn absorption was not significantly (P > 0.05) correlated with Zn intake or with any of the Zn status parameters. Zn absorption was only slightly negatively correlated with serum and erythrocyte Zn levels and with serum Fe and ferritin levels in this study. CONCLUSION: Zn dietary intake and Zn absorption were satisfactory and led to an adequate Zn status in this population.
3503 - Iron status at 12 months of age -- effects of body size, growth and diet in a population with high birth weight.
OBJECTIVE:
To investigate effects of growth and food intake in infancy on iron status at the age of 12 months in a population with high birth weight and high frequency of breast-feeding.
DESIGN:
In a longitudinal observational study infants'' consumption and growth were recorded. Weighed 2 day food records at the ages of 6, 9 and 12 months were used to analyse food and nutrient intake.
SETTINGS:
Healthy-born participants were recruited from four maternity wards. Blood samples and growth data were collected from healthcare centres and food consumption data at home.
SUBJECTS:
Newborn infants (n=180) were selected randomly according to the mother''s domicile and 77% (n=138) participated, of them, 83% (n=114), or 63% of original sample, came in for blood sampling.
RESULTS:
Every fifth child was iron-deficient (serum ferritin <12 microg/l and mean corpuscular volume<74 fl) and 2.7% were also anaemic (Hb<105 g/l). Higher weight gain from 0 to 12 months was seen in infants who were iron-deficient at 12 months (6.7+/-0.9 kg) than in non-iron-deficient infants (6.2+/-0.9 kg) (P=0.050). Serum transferrin receptors at 12 months were positively associated with length gain from 0 to 12 months (adjusted r(2)=0.14/ P=0.045) and mean corpuscular volume negatively to ponderal index at birth (adjusted r(2)=0.14/ P=0.019) and 12 months (adjusted r(2)=0.17/ P=0.006). Iron-deficient infants had shorter breast-feeding duration (5.3+/-2.2 months) than non-iron-deficient (7.9+/-3.2 months/ P=0.001). Iron status indices were negatively associated with cow''s milk consumption at 9-12 months, significant above 460 g/day, but were positively associated with iron-fortified breakfast cereals, fish and meat consumption.
CONCLUSION:
: In a population of high birth weight, iron deficiency at 12 months is associated with faster growth and shorter breast-feeding duration from 0 to 12 months of age. The results suggest that a diet of 9-12-month-olds should avoid cow''s milk above 500 g/day and include fish, meat and iron-fortified breakfast cereals to improve iron status.
Effets de la taille corporelle, de la croissance et du régime alimentaire sur l’état ferrique à l’âge de 12 mois chez 180 enfants ayant un poids de naissance élevé.
Près de 20 % avaient à 12 mois une carence martiale (anémie, baisse de ferritine, diminution du volume corpusculaire). Cette carence martiale était associée à un allaitement au sein de faible durée et une croissance accélérée. Les auteurs suggèrent donc une alimentation pauvre en lait de vache, et enrichie en poissons, en viande et en céréales, riches en fer, pour améliorer le statut ferrique.
3504 - Mechanisms and management of diuretic resistance in congestive heart failure.
Diuretic drugs are used almost universally in patients with congestive heart failure, most frequently the potent loop diuretics. Despite their unproven effect on survival, their indisputable efficacy in relieving congestive symptoms makes them first line therapy for most patients. In the treatment of more advanced stages of heart failure diuretics may fail to control salt and water retention despite the use of appropriate doses. Diuretic resistance may be caused by decreased renal function and reduced and delayed peak concentrations of loop diuretics in the tubular fluid, but it can also be observed in the absence of these pharmacokinetic abnormalities. When the effect of a short acting diuretic has worn off, postdiuretic salt retention will occur during the rest of the day. Chronic treatment with a loop diuretic results in compensatory hypertrophy of epithelial cells downstream from the thick ascending limb and consequently its diuretic effect will be blunted. Strategies to overcome diuretic resistance include restriction of sodium intake, changes in dose, changes in timing, and combination diuretic therapy.
3505 - Improving care for patients with dysphagia
BACKGROUND: Early diagnosis and effective management of dysphagia reduce the incidence of pneumonia and improve quality of care and outcome. Dysphagic stroke patients rarely perceive that they have a swallowing problem, and thus carers have to take responsibility for following the safe swallow recommendations made by the Speech and Language Therapist (SLT). Published work and observations in our own Trust indicated that patients with dysphagia may be fed in a manner which places them at significant risk of aspiration, despite SLT advice for safe swallowing. OBJECTIVE: To determine compliance with swallowing recommendations in patients with dysphagia and to investigate the effectiveness of changes in practice in improving compliance. DESIGN: Sequential observational study before and after targeted intervention. SETTING: An acute general and teaching hospital in an inner city area. SUBJECTS: All patients with dysphagia on the caseload of the speech and language therapy department at the time of the study. METHODS: Observations were made on compliance with the recommendations of SLTs regarding consistency of fluids, dietary modifications, amount to be given at a single meal/drink, swallowing strategies, general safe swallow recommendations and whether supervision was required. A dysphagia link nurse programme was established, together with modification of an in-house training scheme, use of pre-thickened drinks and modification of swallowing advice sheets. The same observations were repeated after this intervention. RESULTS: Thirty-one patients were observed before and 54 after the intervention. There was improvement in compliance with the recommendations on consistency of fluids (48-64%, P<0.05), amount given (35-69%, P<0.05), adherence to safe swallow guidelines (51-90%, P<0.01) and use of supervision (35-67%, P<0.01). There were no significant differences in compliance with dietary modifications or swallowing strategies. Improvement in compliance was demonstrated in medical and geriatric wards and the stroke unit, but not in the surgical wards. Compliance with 'nil by mouth' instructions was 100% throughout. CONCLUSIONS: Relatively simple and low-cost measures, including an educational programme tailored to the needs of individual disciplines, proved effective in improving the compliance with advice on swallowing in patients with dysphagia. It is suggested that this approach may produce widespread benefit to patients across the NHS.
3506 - Inhibition of iron and copper uptake by iron, copper and zinc.
Interactions of micronutrients can affect absorption and bioavailability of other nutrients by a number of mechanisms. In aqueous solutions, and at higher uptake levels, competition between elements with similar chemical characteristics and uptake process can take place. The consequences of these interactions may depend on the relative concentrations of the nutrients. In this work, we measure the effects of increasing concentrations of iron, zinc, and copper on iron and copper uptake in Caco-2 cells. Intracellular Fe or Cu levels were affected by incubating with increased concentrations of metals. However, when the cells already had different intracellular metal concentration, the uptake of Fe or Cu was nor affected. In competition studies, we showed that Cu and Zn inhibited Fe uptake, and while Fe inhibited Cu uptake, Zn did not. When the three metals were given together (1:1:1 ratio), Fe or Cu uptake was inhibited approximately 40%. These results point to a potential risk in the absorption and bioavailability of these minerals by the presence of other minerals in the diet. This aspect must be considered in food supplementation and fortification programs.
Les résultats de cette étude montre un risqué de compétition lors de l’absorption et de l