Daily consumption of a combination of prebiotic short- and long-chain inulin-type fructans significantly increases calcium absorption and enhances bone mineralization during pubertal growth. Effects of dietary factors on calcium absorption may be modulated by genetic factors, including specific vitamin D receptor gene polymorphisms.

No abstract

Non-digestible oligosaccharides such as inulin and oligofructose have been shown to consistently increase calcium absorption in experimental animals, but data in humans are less clearcut. The objective of this study was to assess the effect of 8 g/d of oligofructose or a mixture of inulin and oligofructose on calcium absorption in girls at or near menarche. A total of fiftynine subjects were studied using a balanced, randomized, cross-over design. They received, in random order, 8 g/d placebo (sucrose), oligofructose or the mixture inulin+oligofructose for 3 weeks, separated by a 2-week washout period. Throughout the study, subjects consumed a total of approximately 1500 mg/d dietary calcium, by adding two glasses of calcium-fortified orange juice to their diet. Four grams of placebo, oligofructose or the mixture inulin+oligofruc-tose was added to each glass of orange juice immediately before it was consumed. At the end of each 3-week adaptation period, calcium absorption was measured, using a dual stable isotope technique, from the cumulative fractional excretion of an oral and an intravenous tracer over 48 hours. Calcium absorption was significantly higher in the group receiving the inulin+oligo-fructose mixture than in the placebo group ð38·2^9·8 % v. 32·3^9·8 %; P¼ 0·01), but no significant difference was seen between the oligofructose group and the placebo group ð31·8^9·3 % v. 31·8^10·0 %; P¼NS). We conclude that modest intakes of an inulin+oligo-fructose mixture increases calcium absorption in girls at or near menarche.

Pelvic ultrasound scans were carried out in 153 normal girls aged between 3 days and 14.9 years, in order to obtain reference data for ovarian volume, uterine length and uterine configuration. The right ovary was significantly larger than the left (by about 17%). Ovarian volume increased exponentially with age, over this age range. No relationship with pubertal stage (independent of age) could be demonstrated. Uterine length decreased from birth to 4 years, before steadily increasing. The fundal-cervical ratio (FCR) decreased initially then increased to lie above 1.0 by 15 years of age. A midline endometrial echo was seen in half of the subjects aged less than 6 months, but otherwise it was not seen before 11.8 years of age or at Tanner stage B2. Smoothed reference centile curves for uterine length, right and left ovarian volume were produced, allowing z scores (or SD scores) to be calculated for each measurement.

These data suggest that in adolescents, especially in the presence of vitamin D insufficiency, PTH secretion increases to adapt to higher rates of bone formation associated with growth. This results in higher serum 1,25(OH)2D concentrations and increased calcium absorption results. Vitamin D status, as reflected by the serum 25-OHD level, is not closely related to calcium absorption. Whether adaptation to low serum 25-OHD is adequate under physiologically stressful situations, including those leading to very low serum 25-OHD levels, is unknown.

No abstract

No abstract

The objective of this study was to compare formula intake, the time of weaning, and growth in preterm infants (< or = 1750-g birth weight, < or = 34-wk gestation) fed a standard term or preterm infant formula after initial hospital discharge. Infants were randomized at hospital discharge to be fed a preterm infant formula from discharge to 6 mo corrected age (group A), a term formula from discharge to 6 mo (group B), or the preterm formula (discharge to term) and the term formula (term to 6 mo (group C). Infants were seen biweekly (discharge to term) and monthly (term to 6 mo), when intake was measured and anthropometry and blood sampling were performed. The results were analyzed using ANOVA. Although nutrient intake was similar, at 6 mo girls were lighter (6829 versus 7280 g) and shorter (64.4 versus 66.0 cm) than boys (p < 0.05). Patient characteristics were similar between the treatment groups. Although the volume of intake differed (B > C > A; p < 0.001), energy intake was similar in the groups. Because of differences in formula composition, protein, calcium, and phosphorus intakes differed (B < C < A; p < 0.001). Lower protein intakes were related to lower blood urea nitrogen levels (B < C < A; p < 0.001). At 6 mo, infant boys in B and C were lighter (6933, 6660 < 7949 g), shorter (65.3, 64.9 < 67.1 cm), and had a smaller head circumference (43.7, 43.7 < 44.8 cm; p < 0.05) than infants in group A. Preterm infants were found to increase their volume of intake to compensate for differences in energy density between formulas. After hospital discharge, infant boys fed a preterm formula grew faster than infant girls fed a preterm formula or infant boys fed a term formula.