ABSTRACT
BACKGROUND: Dairy product and calcium consumption have been associated with modifying body fat and body weight in children and adults. OBJECTIVE: In overweight adolescent boys and girls, we aimed to determine the effect of the doubling of habitual calcium intake to the recommended intake from dairy or calcium carbonate on energy balance and purported mechanisms including fecal fat excretion, macronutrient use, and parathyroid hormone suppression. DESIGN: Twenty-five girls with a mean (±SD) BMI (in kg/m(2)) of 33 ± 5 and 17 boys with a BMI of 28 ± 5, aged 12-15 y, participated in two 3-wk controlled feeding sessions that used a crossover design in random order as a summer research camp. In one session, 756 mg Ca/d was consumed; in the other session, an additional 650 mg Ca/d was provided as dairy or calcium carbonate supplements that were matched to the control in macronutrient content. Total energy and macronutrient intakes were controlled and were the same for the 2 sessions for each subject. Primary outcome measures were energy balance, fecal fat excretion, lipid oxidation, and postprandial energy expenditure. RESULTS: There were no effects of quantity or source of calcium on energy or fat balance, despite calcium-induced increases (P <0.01) in postprandial serum parathyroid hormone suppression. CONCLUSION: These data lend little evidence to support the proposed mechanisms for the relation between an increase in calcium intake from calcium carbonate or dairy and weight loss or weight maintenance in children. This trial was registered at clinicaltrials.gov as NCT00592137.
Subject(s)
Calcium, Dietary/administration & dosage , Dairy Products , Energy Intake/physiology , Energy Metabolism/physiology , Overweight/diet therapy , Overweight/metabolism , Adolescent , Calcium, Dietary/metabolism , Calorimetry, Indirect , Child , Cross-Over Studies , Fats/metabolism , Feces/chemistry , Female , Humans , Male , Overweight/blood , Parathyroid Hormone/bloodABSTRACT
BACKGROUND: Several studies have shown a positive effect of fructo-oligosaccharides on calcium absorption and retention in animals and humans. Effects of levels of these pre-biotics that can be functionally incorporated into manufactured foods, have not been studied in controlled feeding studies. OBJECTIVES: This study was designed to evaluate the effect of 9 g/d of fructo-oligosaccharides as part of a controlled diet on calcium absorption and retention in adolescent girls. DESIGN: Fourteen healthy adolescent girls aged 11-13 y were studied in a metabolic setting for two 3-week periods separated by a 2-week washout period. In a randomized, double-blinded, crossover design, the teens received a diet containing either 9 g/d oligofructose-enriched inulin in a calcium-fortified cereal or the control cereal with no inulin. Both diets contained ~1500 mg calcium daily. Calcium retention was determined on the third week of each period. On day 14 of the diet period, fractional calcium absorption was determined from the enrichment of (44)Ca in 4-day urine collections. RESULTS: Calcium absorption (67 ± 3 vs. 66 ± 3%) and retention (409 ± 394 vs. 464 ± 241 mg/d) were not significantly different when diets contained 9 g/d oligofructose-enriched inulin or not in a calcium-fortified cereal. CONCLUSIONS: Daily consumption of cereal containing a combination of short- and long-chain fructo-oligosaccharides as part of a controlled diet did not benefit calcium absorption or retention in adolescent girls. Lack of response to the prebiotic in this cohort may relate to their already high calcium absorption efficiency.
Subject(s)
Calcium, Dietary/pharmacokinetics , Inulin/pharmacology , Oligosaccharides/pharmacology , Prebiotics , Adolescent , Calcium Isotopes/pharmacokinetics , Calcium, Dietary/metabolism , Calcium, Dietary/urine , Child , Cross-Over Studies , Double-Blind Method , Edible Grain , Female , Food, Fortified , Humans , Intestinal AbsorptionABSTRACT
A meta-analysis of 26 studies was conducted to assess whether more complex forms of psychotherapy would be superior to control treatments of either biofeedback, progressive muscle relaxation, or both. Consistent with hypotheses, more complex treatments provided a small, significant improvement over biofeedback and progressive muscle relaxation (r = .09). A subset of the more complex behavioral treatments accounted for most of this small incremental effectiveness of more complex treatments (r = .15). Possible sources of this incremental effectiveness are discussed.