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Background: High infancy weight gain is associated with increased body mass index (BMI) and insulin resistance (IR) in later life, but the association with later body composition has not been well explored. Appetite regulatory hormones may be programmed in early life, but data to support this are lacking. Objective: We investigated the effect of weight gain in infancy on body composition, IR, leptin, ghrelin, and adiponectin at 17 y of age. Design: This was an observational study of 95 term and appropriate-for-gestational-age infants. We measured weight at birth and 9 mo of age and, for a subgroup (n = 60), at 3 and 6 mo of age. Changes in weight SD scores from 0 to 9, 0 to 3, 3 to 6, and 6 to 9 mo of age were calculated. Follow-up examinations at 10 and 17 y of age included body fat (BF) assessment by dual-energy X-ray absorptiometry scanning. We measured serum leptin, ghrelin adiponectin, and IR at 17 y of age. Results: Weight gain from 0 to 9 mo of age was positively associated with BMI (P < 0.003), percentage BF (P < 0.05), and percentage trunk fat (TF) (P < 0.03) but not with percentage TF relative to total BE in childhood and adolescence, and most of these effects were explained by growth from 0 to 3 mo of age. Weight gains from 0 to 9 and 0 to 3 mo of age were not related to IR or leptin but were negatively associated with ghrelin and adiponectin corrected for BF at 17 y of age. Conclusion: Our findings suggest that high weight gain in infancy, especially from 0 to 3 mo of age, has a role in programming both BF and concentrations of ghrelin and adiponectin in adolescence, whereas there was no effect on IR or leptin in this study. doi: 10.3945/ajcn.2009.27956.

Background: Accumulating evidence from observational studies indicates that a high calcium intake may reduce body weight and body fat. However, few randomized trials have been conducted. Objective: We examined whether calcium supplementation affects body weight and body fat in young girls and whether a relation exists between habitual calcium intake and body weight and body fat. Design: A randomized, double-blind, placebo-controlled intervention study was conducted in 110 young girls. The subjects were randomly assigned to receive 500 mg Ca/d as calcium carbonate or placebo for 1 y. Two groups of girls were selected according to habitual calcium intake from a large group; one group consumed 1000-1304 mg/d (40th-60th percentile; n = 60) and the other group consumed Results: At baseline a significant negative correlation was observed between habitual dietary calcium intake and percentage of body fat (r= -0.242, P = 0.011). However, calcium supplementation had no effect on height, body weight, or percentage body fat. Conclusions: Habitual dietary calcium intake was inversely associated with body fat, but a low-dose calcium supplement had no effect on body weight, height, or body fat over 1 y in young girls. It is possible that the effect of calcium on body weight is only exerted if it is ingested as part of a meal, or the effect may be due to other ingredients in dairy products, and calcium may simply be a marker for a high dairy intake. KEY WORDS Children, adolescents, calcium supplementation, habitual calcium intake, body weight, body fat

Background: Single-meal studies have established that calcium has an acute inhibitory effect on the absorption of iron. However, there is growing evidence that high calcium intakes do not compromise iron status. Objective: We evaluated whether long-term calcium supplementation taken with the main meal affected biomarkers of iron status in adolescent girls with high requirements of both iron and calcium. Design: The study was a randomized, double-blind, placebo-controlled trial of supplementation with 500 mg Ca/d for 1 y among 113 adolescent girls aged 13.2 [+ or -] 0.4 y at enrollment. Participants were advised to take the supplement with their evening meal, which usually contributes the majority of dietary iron. Iron status was assessed at baseline and after 1 y of supplementation by measuring hemoglobin and serum concentrations of ferritin and transferrin receptors (TfRs). Results: The mean ([+ or -]SD) hemoglobin at enrollment was 134 [+ or -] 9 g/L, geometric mean serum ferritin was 26.3 [micro]g/L (interquartile range: 18.6-39.4 [micro]g/L), and serum TfR was 4.19 mg/L (3.52-5.10 mg/L). Daily calcium supplementation had no effect on the least-squares mean concentrations of iron-status markers adjusted for their baseline values (hemoglobin: 136 and 134 g/L, P = 0.31: ferritin: 25.4 and 26.1 [micro]g/L, P = 0.73; TfR: 4.1 and 4.4 mg/L, P = 0.12; and the ratio of TfR to ferritin: 160 and 161 in the calcium and placebo groups, respectively: P = 0.97). Conclusion: Although it remains to be shown in iron-deficient persons, long-term iron status does not seem to be compromised by high calcium intakes. KEY WORDS Iron status, intervention, calcium supplementation, calcium intake, adolescence, puberty, girls

Background: There is no agreement on how much calcium young girls need for optimal bone mineralization. Objective: We evaluated whether the effect of calcium supplementation on whole-body bone mineral accretion depends on habitual calcium intake. Design: This was a randomized, double-blind, placebo-controlled, 1-y calcium intervention study of girls aged 12-14 y selected from a larger group according to habitual calcium intake: subgroup A (n = 60) habitually consumed 1000-1307 mg/d (40th-60th percentile), and subgroup B (n = 53) habitually consumed Results: There was no significant effect modification of baseline habitual calcium intake on the relation between calcium supplementation and height, weight, BMC, size-adjusted BMC, BA, BMD, or alkaline phosphatase. Calcium supplementation had an effect on BMD (0.8%; P = 0.049) and tended to show signs of an effect on size-adjusted BMC (0.5%; P = 0.08). Conclusion: A modest effect of calcium supplementation on BMD was shown. However, the effect was independent of habitual calcium intake. KEY WORDS Young girls, bone mineral content, calcium intervention, habitual calcium intake

Background: Studies from developing countries indicate that intake of animal protein, especially of milk, is associated with greater velocity of linear growth in childhood. Whether the same association exists in industrialized countries, where protein intake is high, is not clear. Objective: Our objective was to examine associations between protein intake, serum insulin-like growth factor I (sIGF-I) concentrations, and height in healthy children. Design: We analyzed the associations between protein intake, sIGF-I concentrations, and height in 2.5-y-old children. Diet (7-d record) and sIGF-I (radioimmunoassay) data were available from 90 children (54 boys). Results: The 10th, 50th, and 90th percentiles of protein intake were 2.4, 2.9, and 4.0 g x [kg.sup.-1] x [d.sup.-1], respectively; 63% was animal protein. In multiple linear regressions with adjustment for sex and weight, height (cm) was positively associated with intakes of animal protein (g/d) [0.10 [+ or -] 0.038 (b [+ or -] SE); P = 0.01] and milk (0.0047 [+ or -] 0.002; P = 0.007), but not with those of vegetable protein or meat. The sIGF-I concentration was significantly associated with intakes of animal protein (1.4 [+ or -] 0.53; P = 0.01) and milk (0.049 [+ or -] 0.024; P = 0.045), but not with those of vegetable protein or meat. sIGF-I concentrations were positively associated with height (0.019 [+ or -] 0.008; P = 0.02). Conclusion: Milk intake was positively associated with sIGF-I concentrations and height. An increase in milk intake from 200 to 600 mL/d corresponded to a 30% increase in circulating IGF-I. This suggests that milk compounds have a stimulating effect on sIGF-I concentrations and, thereby, on growth. KEY WORDS Dietary protein, animal protein, vegetable protein, children, insulin-like growth factor I, milk, meat, growth

Background: During the complementary feeding period, infants shift from a daily protein intake (PI) of [approximately equal to] 1 g/kg body wt to an intake 3-4 times as high. A high PI probably has both endocrine and physiologic effects and may increase the risk of obesity. Objective: We examined the associations between PI in infancy and body size and composition in late childhood. Design: We conducted an observational cohort study of 142 Danish healthy term infants (63 boys) born during 1987-1988. At 9 mo of age, diet, weight, length, skinfold thicknesses, insulin-like growth factor I, and serum urea nitrogen were determined. At 10 y of age, 105 children (51 boys) participated in a follow-up study. Diet, weight, height, skinfold thicknesses, percentage of body fat (dual-energy) X-ray absorptiometry), insulin-like growth factor I, and serum urea nitrogen were determined. Results: At 9 mo of age, PI (in g/d and percentage of energy) was strongly correlated with body size (length and weight) but not with measures of adiposity. PI at 9 mo of age was positively associated with height and weight but not with percentage of body fat at l0 y of age. Inclusion of parental body size in the models did not change the associations, but the significant associations were attenuated when body size at 9 mo of age was included. Conclusions: PI in infancy seems to stimulate early growth. This might explain part of the association between early PI and body size at 10 y of age, but a continuous effect of protein on growth during childhood cannot be excluded. PI in infancy was not associated with any measure of body fat at 10 y of age. KEY WORDS Protein-adiposity hypothesis, infancy, childhood, breastfeeding, growth, obesity, insulin-like growth factor I, protein intake

Background: Dietary calcium absorption can be determined only with the use of isotope techniques. Currently used isotope techniques require exclusive equipment or are not true tracer approaches. Objective: The objective was to compare a dual-isotope method combining radioisotopes and stable isotopes with a whole-body radioisotope retention method for measuring calcium absorption. Design: Seven healthy adults aged 21-27 y consumed a test meal containing 63 [+ or -] 14 ([bar]x [+ or -] SD) mg Ca together with a water solution of [sup.47]Ca (0.11 MBq). One hour after ingestion, 18 mg [sup.44]Ca was administered intravenously. All feces and urine were collected for 5 and 6 d, respectively. Calcium absorption was estimated from whole-body retention of the radioisotope 12 times over 3 wk after ingestion and from the excretion of [sup.47]Ca and [sup.44]Ca in a 24-h urine sample collected on day 2. [sup.44]Ca in urine was determined by inductively coupled plasma mass spectrometry. Results: Mean ([+ or -] SD) calcium absorption was 75 [+ or -] 9% with the dual-isotope method and was 74 [+ or -] 8% with the whole-body radioisotope retention method. There was a high degree of agreement between the methods. Conclusion: The dual-isotope method is a valid approach for measuring calcium absorption from a single meal. KEY WORDS Calcium absorption, radioisotopes, [sup.47]Ca, stable isotopes, [sup.44]Ca, whole-body counting, inductively coupled plasma mass spectrometry, ICPMS

The long-term effect of dietary protein on bone mineralisation is not well understood. Observational data support that a high protein intake is associated with an enhanced bone loss, but the opposite finding has also been reported. Sixty-five overweight or obese subjects (25