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BACKGROUND: A high early protein intake has been proposed to increase obesity risk. OBJECTIVE: We examined whether a critical period of protein intake for later obesity may exist early in childhood and investigated the relation between protein intake from different sources and body mass index SD score and body fat percentage (BF%) at 7 y of age. DESIGN: The study population included 203 participants of the Dortmund Nutritional and Longitudinally Designed Study with information on diet at 6 mo, 12 mo, 18-24 mo, 3-4 y, and 5-6 y. Life-course plots were constructed to assess when protein intake (% of energy) was associated with body mass index SD score and BF% at 7 y. Mean values were then compared among tertiles (T1-T3) of protein from different sources at the important time points. RESULTS: The ages of 12 mo and 5-6 y were identified as critical ages at which higher total and animal, but not vegetable, protein intakes were positively related to later body fatness. In fully adjusted models, animal protein intake at 12 mo was associated with BF% at 7 y as follows [x (95% CI) BF%]: T1, 16.20 (15.23, 17.25); T2, 17.21 (16.24, 18.23); T3, 18.21 (17.12, 19.15); P for trend = 0.008. With respect to food groups, dairy, but not meat or cereal protein intake, at 12 mo was related to BF% at 7 y (P for trend = 0.07). Animal protein at 5-6 y yielded similar results (P for trend = 0.01), but food group associations were less consistent. CONCLUSION: A higher animal, especially dairy, protein intake at 12 mo may be associated with an unfavorable body composition at 7 y. The age of 5-6 y might represent another critical period of protein intake for later obesity risk. [ABSTRACT FROM AUTHOR]

BACKGROUND: Anthropometric measurements are widely used to determine body composition, especially in children. OBJECTIVE: Our aim was to compare 2 of the simplest anthropometry-based equations available for determining nutritional status and muscularity in children and adolescents, examined in relation to other methodologically independent muscle variables. DESIGN: Midupper arm muscle area (UAMA) and fat-free mass (FFM) according to the equations of Slaughter et al (Hum Biol 1988;60:709-23), as well as separate biochemical, physical, and radiologic muscle variables, were determined cross-sectionally in 91 males and 91 females aged 6-18 y. The ability of UAMA and FFM to estimate muscularity, as measured by 24-h creatinine excretion, grip force, and peripheral quantitative computer tomography analysis of forearm muscle, was compared after dividing the study population into prepubertal and pubertal groups. RESULTS: Before puberty, correlations of all 3 muscularity variables were higher with FFM than with UAMA in both males and females. Multiple regression analyses confirmed FFM to be the predominant predictor, with partial R(2) >/= 0.68 (P < 0.001). However, in puberty, FFM did not consistently show this major influence. Only before puberty did FFM provide a significantly better fit (P < 0.05) than did UAMA for 2 of the 3 muscularity variables in each sex. CONCLUSIONS: The FFM estimate proved to be the better predictor for muscularity in healthy prepubertal children and is on a par with UAMA during puberty. FFM can be recommended as a simple anthropometric method to assess nutritional status before puberty, at least in healthy children. Copyright © 2002 American Society for Clinical Nutrition [ABSTRACT FROM AUTHOR]

Background: Reduced net acid excretion (NAE) capacity indicates a decrease in renal function. This reduction manifests as a disproportionally low 24-h urine pH in relation to the sum of actually excreted ammonium and titratable acidity by the kidney., Objective: The aim of this study was to test the hypothesis that higher body fatness is one determinant of kidney function impairment with a lowered urine pH even at a young age., Methods: NAE, pH, urea, and creatinine were measured in 24-h urine samples from 524 healthy children and adolescents (aged 6-17 y) participating in the DOrtmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study. Body fatness was assessed anthropometrically by body mass index-standard deviation score (BMI-SDS), fat mass index (FMI), body fat % (BF%), and waist circumference (WC). Multivariable linear and mixed linear regressions were used to examine cross-sectionally (n = 524 urine samples; age groups: 6-8, 9-11, 12-14, 15-17 y) and longitudinally (n = 1999 urine samples) the associations of body fatness with 24-h urine pH as the outcome variable, respectively., Results: After adjusting for the kidneys' total net acid load (24-h urinary NAE) and further relevant covariates, FMI showed significant inverse relations with urinary pH in all 4 age groups, and BMI-SDS, BF%, and WC each in 3 out of these 4 groups (P ≤ 0.02). Longitudinal results substantiated these interindividual relations and further showed intraindividual increases in body fatness to be paralleled by urine pH decreases (P ≤ 0.0002)., Conclusions: Independent of underlying acid load, an early increase in body fatness is associated with increased free proton excretion, and thus with a decline in the kidney's acid excretion function, which could potentiate the risk of renal nephrolithiasis., (Copyright © American Society for Nutrition 2019.)

Background: The specific effects of fruit and vegetable (F&V) intake on water balance and consequently on 24-h hydration status (HS) are unknown., Objectives: In a large observational cohort of German children, we examined whether a higher F&V intake per se is associated with improved HS and attempted to quantify the influence of greater consumption of F&Vs on HS., Design: A total of 1286 complete 3-d weighed dietary records and 24-h urine samples for 442 children (4- to 10-y-olds) collected in 2000-2010 in the Dortmund Nutritional and Anthropometric Longitudinally Designed Study were analyzed. Free water reserve [FWR; urine volume (mL/24 h) minus obligatory urine volume (mL/24 h)] served as an HS biomarker. Median FWR and water balance variables were analyzed in different categories of solid-F&V intakes. Repeated-measures regression models (PROC MIXED; SAS Institute), adjusted for all other dietary water sources, were used to quantify the separate effects of solid-F&V and F&V-juice consumption on FWR., Results: Negative FWR values, which indicated risk of hypohydration, were observed in 22% of children. FWR was significantly higher in solid-F&V consumers with high intakes than in those with low intakes (P < 0.0001). PROC MIXED models predicted an increase of 46 mL in FWR (average in boys and girls) when increasing solid-F&V intake by 100 g. Similar results were observed for F&V juice (β = 43, P < 0.0001). Drinking water and milk were the other significant dietary predictors of FWR. Solid F&Vs and F&V juices contributed 12% and 10%, respectively, to total water intake., Conclusions: These data confirm that regular intake of F&Vs may relevantly improve HS in children. Dietary interventions to increase F&V intake may be a promising strategy to achieve positive water balance in this population.

Background: The reduced activity of 11β hydroxysteroid dehydrogenase type 2 (11βHSD2) contributes to elevated blood pressure (BP) in clinical syndromes, but its effect on BP in the physiologic range is unclear., Objectives: We examined the association of 11βHSD2 activity with BP in healthy children independent of known BP-related dietary and other factors and determined whether the diet-dependent acid load may constitute a dietary factor related to BP., Design: We conducted a cross-sectional analysis in 267 healthy children (age range: 4-14 y) who provided a 24-h urine sample, a parallel 3-d weighed dietary record, and 1-3 BP measurements ±1.5 y around the urine collection. The ratio of urinary free cortisone to cortisol measured by using a radioimmunoassay was used as an index for 11βHSD2. Urinary net acid excretion and the urinary and dietary potential renal acid load (PRAL) were used to predict the diet-dependent acid load. The PRAL was calculated as the sum of major mineral nonbicarbonate anions minus the sum of mineral cations. Sex-, age- and height-independent SD scores (SDSs) of systolic and diastolic BP were used as outcomes in linear regression analyses., Results: 11βHSD2 was inversely associated with systolic BP SDSs in basic models and in analyses adjusted for body size, maternal BP, breastfeeding, and dietary intakes of total energy, salt, and fruit and vegetables (P = 0.03). In models that included indexes of dietary acid load instead of fruit and vegetables, all 3 acid-load biomarkers were significantly (P = 0.006-0.02) directly related to systolic BP., Conclusion: A lower 11βHSD2 activity and higher dietary acid load may independently contribute to higher systolic BP in healthy children.

Background: It has been suggested that phytoestrogens and dietary fiber can affect puberty timing., Objective: We examined whether intake of isoflavone and fiber in healthy white children before their pubertal growth spurt [age at take-off (ATO)] was associated with puberty timing., Design: Multivariate regression analyses were performed in 227 DONALD (DOrtmund Nutritional and Anthropometric Longitudinally Designed) Study participants with 3-d weighed dietary records and information on potential confounders at baseline (1 and 2 y before ATO). In a subsample (n = 111), urinary isoflavones were determined in 24-h urine samples by gas chromatography-mass spectrometry analysis. Puberty timing was examined by using ATO and chronologic ages at pubertal stage 2 for breast development (B2) or gonadal development, peak height velocity (PHV), and menarche or voice break., Results: Girls whose diet was in the highest dietary isoflavone tertile experienced Tanner stage 2 for breast development ap 0.7 y later and reached PHV ap 0.6 y later than did girls whose diet was in the lowest isoflavone tertile [age (95% CI) at B2: 10.7 y (10.4, 10.9 y) compared with 10.0 y ( 9.7, 10.3 y), respectively; P for trend = 0.04; age at PHV: 11.9 y (11.6, 12.2 y) compared with 11.3 y (11.0, 11.6 y), respectively; P for trend = 0.04; adjusted for body mass index z score and fiber intake]. In boys, dietary isoflavones were not associated with pubertal markers. Urinary isoflavone and dietary fiber intakes were not associated with pubertal markers., Conclusions: Girls, but not boys, with higher prepubertal isoflavone intakes appear to enter puberty at a later age. Fiber intake in this sample of healthy white girls and boys was not relevant for puberty timing.

Background: Adrenarche is the increase in adrenal androgen (AA) production starting in childhood. Until now, it has been unknown whether or not nutritional factors modulate adrenarche., Objective: The objective was to examine whether body composition and certain dietary intakes are associated with AA production in children after accounting for urinary indicators of major adrenarche-related steroidogenic enzymes., Design: Androgen and glucocorticoid metabolites were profiled by gas chromatography-mass spectrometry in 24-h urine samples of 137 healthy prepubertal children aged 3-12 y, for whom birth characteristics, growth velocity data, and 3-d weighed-diet record information were available. Associations of the sum of C19 metabolites (reflecting daily AA secretion) with nutritional factors [fat mass (FM), fat-free mass (FFM), nutrient intakes, glycemic index, and glycemic load] and AA-relevant estimates of steroidogenic enzyme were examined in stepwise multiple regression models adjusted for age, sex, urine volume, and total energy intake. Enzyme activity estimates were calculated by using specific urinary steroid metabolite ratios., Results: Of the nutrition-relevant predictors, FM (P < 0.0001) explained most of the variation of AA secretion (R(2) = 5%). Animal protein intake was also positively associated with AA secretion (P < 0.05), which explained 1% of its variation. FFM (P = 0.1) and total protein intake (P = 0.05) showed positive trends. The difference in daily AA secretion between the lowest and highest quartile of FM was comparable to that between the lowest and highest estimated activity of one of the major steroidogenic enzymes., Conclusions: Body fat mass may relevantly influence prepubertal adrenarchal androgen status. In addition, animal protein intake may also make a small contribution to AA secretion in children.

Background: It is controversial whether prepubertal body composition is implicated in the timing of puberty onset., Objective: The objective was to investigate whether body composition in the 2 y preceding the start of the pubertal growth spurt -- a marker of puberty onset -- is associated with the attainment of early and late pubertal markers in healthy German boys and girls., Design: Multivariate-adjusted regression analyses were performed in 215 participants of the DOrtmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study for whom body mass index (BMI) and its components fat mass/height(2) (FM/m(2)) and fat-free mass/height(2) (FFM/m(2)) 1 and 2 y before the onset of the pubertal growth spurt (age at takeoff; ATO) and information on early life exposures were available. In addition, age at peak height velocity (APHV) and menarche were examined., Results: Higher BMIs and FM/m(2) z scores 1 and 2 y before ATO showed modest associations with chronological age at ATO among girls only (girls: P for = trend 0.05-0.1, adjusted for early life factors; boys: P = 0.2-0.6). FFM/m(2) z scores were not related to age at ATO (P for trend = 0.5-0.8). Conversely, prepubertal BMI and FM/m(2) more clearly predicted APHV and puberty duration (APHV minus ATO) in both sexes and age at menarche in girls (girls: adjusted P for trend <0.0001-0.03; boys: P = 0.01-0.046)., Conclusion: This longitudinal study suggests that prepubertal body composition in healthy boys and girls may not be critical for the initiation of the pubertal growth spurt but instead affects the progression of pubertal development, which results in earlier attainment of later pubertal stages.

Background: Soft drinks are thought to displace milk in diets of children and adolescents and therefore might affect variables of bone modeling and remodeling., Objective: We assessed the association between long-term consumption of several types of soft drinks and bone variables in children and adolescents., Design: Long-term dietary data from 3-d weighed dietary records collected by 228 healthy children and adolescents enrolled in the DONALD Study in 4 y of study participation were used for data analysis. Variables of bone modeling and remodeling of the radius were assessed by using peripheral quantitative computed tomography., Results: After adjustment for age, sex, total energy intake, muscle area, BMI SD scores, and growth velocity, long-term consumption of all soft drinks and uncaffeinated soft drinks was negatively associated with bone mineral content (P < 0.05), cortical area (P < 0.05), and polar strength strain index (P < 0.05), all of which reflect a combination of bone modeling and remodeling. Long-term consumption of caffeinated soft drinks was negatively associated with polar strength strain index (P < 0.01) and periosteal circumference (P < 0.05), which reflect bone modeling. Milk intake was positively associated with polar strength strain index (P < 0.05). Consumption of all soft drinks was negatively associated with total protein and milk intake, but was not associated with potential renal acid load., Conclusions: Long-term consumption of caffeinated and uncaffeinated soft drinks appears to have bone catabolic effects in boys and girls. This effect is mainly mediated by the negative association with total protein intake and is not primarily based on milk displacement.

Background: Observational studies in adults suggest that a diet with a high glycemic index (GI) or glycemic load (GL), a high intake of sugary foods, or a low fiber intake may increase the risk of overweight., Objectives: We aimed to examine prospectively whether dietary GI, GL, added sugar intake, or fiber intake between age 2 and 7 y are associated with the development of body composition. If so, we aimed to ascertain whether these associations are modified by meal frequency., Design: Linear mixed-effect regression analyses were performed in 380 participants of the DOrtmund Nutrition and Anthropometric Longitudinally Designed (DONALD) Study for whom 4-6 weighed 3-d dietary records and anthropometric data were obtained between ages 2 and 7 y., Results: Changes in dietary GI, GL, or added sugar intake between ages 2 and 7 y were not associated with concurrent changes in percentage body fat (%BF, as estimated from skinfold thicknesses) or body mass index SD scores. An increase in fiber intake was related to a concurrent decrease in %BF between ages 2 and 7 y only in children who consumed <6 meals/d as toddlers (beta +/- SE from fully adjusted model: -0.26 +/- 0.09%BF per 1-SD increase in fiber intake, P = 0.005), whereas children with a higher meal frequency had no concurrent change (0.07 +/- 0.07%BF per 1-SD increase in fiber intake, P = 0.3)., Conclusions: Dietary GI, GL, or added sugar intake between ages 2 and 7 y does not appear to influence the development of body composition. Potential benefits associated with increasing fiber intake throughout childhood may be limited to toddlers with a lower meal frequency.

Background: Experimental studies have reported that the effect of a meal's glycemic index (GI) on subsequent energy intake depends on the timing of the subsequent meal., Objective: We examined whether the timing of the next meal after breakfast modifies the effect of the breakfast GI (GI(br)) on subsequent daytime energy intake of healthy free-living children., Design: Analyses included 381 participants of the DOrtmund Nutritional and Anthropometrical Longitudinally Designed (DONALD) Study who had provided weighed dietary records at ages 2, 4-5, and 7 y., Results: At all ages, among children who consumed their next meal in the early postprandial phase (after 3-4 h), children with a lower GI(br) consumed more calories throughout the remainder of the day than did children with a higher GI(br), independent of major dietary confounders. For the age groups 2, 4-5, and 7 y, energy intakes in tertiles 1 and 3 were 785 kcal (95% CI: 743-830 kcal) and 717 kcal (678-758 kcal), P for trend = 0.2; 993 kcal (941-1047 kcal) and 949 kcal (900-1000 kcal), P for trend = 0.05; 1255 (1171-1344) and 1166 (1090-1247 kcal), P for trend = 0.03, respectively. Conversely, among children consuming their next meal in the late postprandial phase (>3-4 h), subsequent daytime energy intake was not associated with GI(br)., Conclusion: This study confirms differential early and late postprandial effects of the GI(br) on subsequent daytime energy intake for free-living children at different ages. Interestingly, the apparent short-term satiating effect of a higher GI(br), in particular, persisted throughout the day, if a second breakfast was consumed midmorning.

Background: Because worldwide iodine status (IS) depends on continuous fortification, the adequacy of IS needs to be regularly monitored., Objective: Our study aimed to evaluate IS in a longitudinal sample of healthy schoolchildren who regularly used table salt iodized with 20 microg I/g., Design: Urine osmolality (Uosm) and 24-h urinary excretion rates of iodine (24-h UI), sodium, creatinine, and total urine volume (24-h Uvol) were measured in 1046 specimens that were collected at repeated intervals from 1996 to 2003 in a sample of 358 German children aged 6-12 y. Energy intake and food consumption were calculated from 3-d weighed dietary records that were collected in parallel to the urine samples., Results: During the 4-y period from 1996 to 1999, the median 24-h UI increased from 87 to 93 microg I/d (P = 0.017), whereas urinary iodine concentration (UIC), Uosm, and 24-h Uvol did not change significantly. Thereafter (from 2000 to 2003), UIC stagnated and Uosm decreased (P = 0.004), whereas 24-h Uvol (P = 0.008) and 24-h UI (P = 0.002) increased. The final median 24-h UI reached 120 microg I/d. Milk, fish, egg, and meat intakes and 24-h sodium excretion were all significant predictors of IS, with an almost doubled contribution from milk intake during the second 4-y period., Conclusions: Our study shows a continuous improvement of IS in a longitudinal sample of German schoolchildren. This improvement was masked when UIC was used as an IS index, especially from 2000 to 2003 because of changes in hydration status. Thus, in research-oriented studies that focus on UIC measurements, hydration status can be a relevant confounder. Longitudinal analyses of 24-h UI in cohort studies may represent an alternative hydration status-independent tool to examine trends in IS and the contribution of relevant foods to IS.

Background: Protein and alkalizing minerals are increasingly described as playing a major role in influencing bone status, not only in the elderly but also in children and adolescents., Objective: We examined whether the long-term dietary protein intake and diet net acid load are associated with bone status in children., Design: In a prospective study design in 229 healthy children and adolescents aged 6-18 y, long-term dietary intakes were calculated from 3-d weighed dietary records that were collected yearly over the 4-y period before a one-time bone analysis. Dietary acid load was characterized as potential renal acid load (PRAL) by using an algorithm including dietary protein, phosphorus, magnesium, and potassium. Proximal forearm bone variables were measured by peripheral quantitative computed tomography., Results: After adjustment for age, sex, and energy intake and control for forearm muscularity, BMI, growth velocity, and pubertal development, we observed that long-term dietary protein intake was significantly positively associated with periosteal circumference (P < 0.01), which reflected bone modeling, and with cortical area (P < 0.001), bone mineral content (P < 0.01), and polar strength strain index (P < 0.0001), which reflected a combination of modeling and remodeling. Children with a higher dietary PRAL had significantly less cortical area (P < 0.05) and bone mineral content (P < 0.01). Long-term calcium intake had no significant effect on any bone variable., Conclusions: Long-term dietary protein intake appears to act anabolically on diaphyseal bone strength during growth, and this may be negated, at least partly, if dietary PRAL is high, ie, if the intake of alkalizing minerals is low.

Background: There is increasing evidence that acid-base status has a significant effect on high-intensity physical performance, urolithiasis, and calcium metabolism. Experimental studies in adults showed that renal net acid excretion (NAE) can be reliably estimated from the composition of diets., Objective: We investigated whether a reasonable estimation of NAE is also possible from the dietary records of free-living children and adolescents., Design: Healthy children (aged 8 y; n = 165) and adolescents (aged 16-18 y; n = 73) each collected a 24-h urine sample and completed a weighed diet record on the same day. Urinary NAE was analyzed (NAE(an)) and estimated (NAE(es)). Potential renal acid load (PRAL), the diet-based component of NAE(es), corrects for intestinal absorption of ingested minerals and sulfur-containing protein. A urinary excretion rate of organic acids (OAs) proportional to body surface area was assumed for the complete estimate (NAE(es) = PRAL + OA(es))., Results: Significant (P < 0.001) correlations between NAE(es) and NAE(an) were seen in the children (r = 0.43) and the adolescents (r = 0.51). A simplified estimate based on only 4 components of dietary PRAL (protein, phosphorus, potassium, and magnesium) yielded almost identical associations. Mean simplified NAE(es) (32.6 +/- 13.9 and 58.4 +/- 22.0 mEq/d in the children and the adolescents, respectively) agreed reasonably with NAE(an) (32.4 +/- 15.5 and 52.8 +/- 24.3 mEq/d, respectively)., Conclusions: Predicting NAE from dietary intakes, food tables, and anthropometric data is also applicable during growth and yields appropriate estimates even when self-selected diets are consumed. The PRAL estimate based on only 4 nutrients may allow relatively simple assessment of the acidity of foods and diets.

Background: Excess endogenous or exogenous cortisol is a potent stimulus for fat gain., Objective: We examined whether physiologic variations in endogenous cortisol secretion may be associated with changes in body composition during growth., Design: Anthropometric measurements and 24-h excretion rates of urinary free cortisol (UFF) and cortisone (UFE) and the sum of 3 major glucocorticoid metabolites (GC), which reflects overall daily cortisol secretion, were determined cross-sectionally in healthy preschool (50 boys and 50 girls aged 4-5 y), late prepubertal (50 boys and 50 girls aged 8-9 y), and pubertal (50 males aged 13-14 y and 50 females aged 12-13 y) subjects., Results: Significant positive associations (P < 0.001) were found between GC excretion and fat mass, percentage body fat, and body mass index by using covariance analysis adjusted for the grouping factors sex and age. The relations between GC and indexes of body fat remained significant (P < 0.05) even after GC was corrected for individual body surface area and the effect of maternal body mass index on fatness was considered. No consistent associations with fat indexes were seen for UFF, UFE, or the ratio of major urinary cortisol to cortisone metabolites, which reflects 11 beta-hydroxysteroid dehydrogenase type 1 activity., Conclusions: Although direct effects of UFF and UFE on body composition were not shown, our findings strongly suggest that a higher adrenocortical activity is one endocrine-metabolic feature of healthy children with higher body fat. Whether urinary GC is a long-term predictor of fat gain during childhood should be analyzed in future studies.

Background: Urinary creatinine reference values that take anthropometric data into account, which is mandatory during growth, are not available for healthy white children., Objective: We sought to establish anthropometry-based reference values for 24-h urinary creatinine excretion in healthy white children aged 3-18 y., Design: Anthropometric variables and 24-h urinary creatinine excretion rates were determined cross-sectionally (225 boys and 229 girls). Age and sex dependency of 24-h creatinine excretion (crude and related to individual anthropometric variables) were assessed to derive appropriate creatinine reference values. The applicability of these creatinine reference values for estimation of daily excretion of certain analytes was assessed in 40 additional children., Results: Sex-specific, body-weight-related creatinine reference values were derived for the following age groups: 3, 4-5, 6-8, 9-13, and 14-18 y. The 5th percentile exceeded 0.1 mmol x kg(-1) x d(-1) in all age groups >3 y. The use of these creatinine reference values for estimating average 24-h excretion rates of certain analytes (determined as the ratio of analyte to creatinine in spot urine samples) yielded reasonable estimates of mean 24-h urinary excretion rates actually analyzed (spot and 24-h urine samples from the same children). Ideal 24-h creatinine excretion values for height were also derived for a potential determination of the creatinine height index., Conclusions: Established anthropometry-based creatinine reference values are recommended as a convenient, simple tool to 1) identify severe 24-h urine collection errors, 2) calculate average 24-h excretion rates of certain analytes (from respective ratios of analyte to creatinine) determined in spot urine samples, and 3) assess somatic protein status by determining the creatinine height index.

The object of this study was to determine whether it is possible to reliably estimate the renal net acid excretion (NAE) produced by adults consuming different amounts of dietary protein. A physiologically based calculation model that corrects for intestinal absorption of minerals and sulfur-containing protein and assumes a rate of urinary excretion of organic acids proportional to body surface area was used to estimate NAE. Urinary excretion of different minerals and NAE was measured during the last 48 h of each of four separate 5-d diet periods in six healthy adults. On the basis of food tables, the four nearly isoenergetic diets (one lacto-vegetarian and one high- and two moderate-protein diets) were estimated to yield the following NAE values: 3.7, 117.5, 62.2, and 102.2 mEq/d, respectively. The analytically determined urinary NAE (24.1 +/- 10.7, 135.5 +/- 16.4, 69.7 +/- 21.4, and 112.6 +/- 10.9 mEq/d) corresponded reasonably well to these estimates, suggesting that the calculation model is appropriate to predict the renal NAE from nutrient intake and anthropometric data.