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2023 MAR 4 (NewsRx) -- By a News Reporter-Staff News Editor at Obesity, Fitness & Wellness Week -- Investigators publish new report on colon cancer. According to news reporting out [...]

Background: Few calcium balance data are available from young children on which to base dietary recommendations. Objective: The objective of the study was to evaluate the relation between calcium intake and balance in healthy children aged 1-4 y consuming typical American diets. Design: Subjects were assigned to a diet with nutrient intakes similar to those of their usual diet. Calcium absorption was assessed by using a dual-tracer stable-isotope technique. Endogenous fecal excretion was measured in a subset of children, and net calcium balance was calculated. Results: Mean calcium intake was 551 mg/d (range: 124-983 mg/ d), and mean ([+ or -] SEM) calcium retention was 161 [+ or -] 17 mg/d. Both linear and nonlinear modeling of balance data showed that a calcium intake of [approximately or equal to] 470 mg/d led to calcium retention of 140 mg/d, which is the amount that meets expected bone growth needs in children of this age. No evidence was found that calcium intakes of 800 to 900 mg/d reached the threshold intake beyond which no additional increase in calcium retention would occur. Conclusions: Bone growth needs in l-4-y-old children following American diets are met by a daily calcium intake of [approximately or equal to] 470 mg/d, which suggests that the current Adequate Intake of 500 mg/d is close to the actual Estimated Average Requirement. The benefits and risks of higher calcium intakes consistent with threshold values should be evaluated in a controlled trial before those intakes could be used as a basis for dietary recommendations. Am J Clin Nutr 2007;85: 750-4. KEY WORDS Calcium absorption, stable isotopes, bioavailability, nutrient requirements

Background: Calcium intake in North America remains substantially below recommended amounts. Bottled waters high in calcium could help close that gap. Objectives: The objectives were to summarize and integrate published absorbability and biodynamic data concerning high-calcium mineral waters and to combine these data with hitherto unpublished analyses from my laboratory. Design: The usual library database was searched. The absorbability of calcium from a high-mineral water labeled with tracer quantities of [sup.45]Ca was measured in human volunteers as a part of an otherwise low-calcium test meal. Published reports that used differing load sizes and meal conditions were harmonized by making corrections based on published calcium absorbability data. Results: All the high-calcium mineral waters had absorbabilities equal to milk calcium or slightly better. When tested, all produced biodynamic responses indicative of absorption of appreciable quantities of calcium (ie, increased urinary calcium, decreased serum parathyroid hormone, decreased bone resorption biomarkers, and protection of bone mass). Conclusion: High-calcium mineral waters could provide useful quantities of bioavailable calcium. KEY WORDS Calcium, calcium absorption, mineral water, calcium bicarbonate, calcium sulfate, bone resorption

Background: Concern that long-term weight retention after pregnancy contributes to obesity underscores the need to identify factors that facilitate postpartum weight loss. Lactation is believed to facilitate postpartum weight loss and fat loss. Calcium intake also has been hypothesized to promote weight loss and fat loss. Objective: We addressed the following questions: 1) whether lactation enhances loss of fat mass, and 2) whether loss of fat mass during lactation and after weaning is greater in women receiving calcium supplementation than in women receiving placebo. Design: We used data from 87 lactating and 81 nonlactating women enrolled in a randomized, double-blind, calcium supplementation trial from 2 wk to 6 mo postpartum and data from 76 previously lactating and 82 nonlactating women enrolled in a parallel trial from 6 to 12 mo postpartum. Body fat and lean masses were measured by using dual-energy X-ray absorptiometry. Results: Nonlactating women lost whole-body, arm, and leg fat at a faster rate than did lactating women between 2 wk and 6 mo postpartum (lactation group x time effect, P [greater than or equal to] 0.01). Fat mass of the trunk, arms, and legs decreased between 6 and 12 mo postpartum regardless of previous lactation status (time effect, P [less than or equal to] 0.001). Calcium supplementation did not affect postpartum fat loss. Conclusions: Body-composition changes occur differently in nonlactating and lactating women during the first 6 mo postpartum and occur at some sites until 12 mo postpartum regardless of previous lactation status. Clinicians should use caution when advising lactating mothers about expected rates of postpartum fat loss. Calcium supplementation (1 g/d) does not promote postpartum weight loss or fat loss. KEY WORDS Lactation, weaning, postpartum women, body composition, calcium, fat mass, obesity, breastfeeding

Background: Physiologic adjustments in calcium homeostasis during pregnancy and lactation in women with marginal calcium intakes have not been described. Objective: The objective was to examine longitudinal changes in various aspects of calcium homeostasis during pregnancy and lactation in 9 healthy Brazilian women who habitually consumed [approximately equal to]500 mg Ca/d. Design: Calcium homeostasis was assessed at 3 time points: 10-12 (early pregnancy, EP) and 34-36 (late pregnancy, LP) wk of pregnancy and 7-8 wk postpartum (early lactation, EL). At each time point, the following variables were measured: dietary calcium intake with a 3-d weighed food record, 24-h urinary calcium excretion (UCa), intestinal calcium absorption (%CaAbs) via administration of stable calcium isotopes with a breakfast meal, serum 1,25-dihydroxyvitamin D, parathyroid hormone (PTH), insulin-like growth factor I (IGF-I), and biochemical markers of bone turnover. Results: Dietary calcium did not change during the study. %CaAbs increased from 69.7 [+ or -] 5.4% (2 [+ or -] SEM) during EP to 87.6 [+ or -] 4.5% during LP (P < 0.05) and returned to 65.1 [+ or -] 6.2% during EL. Compared with EP, UCa decreased 22% during LP and 68% during EL (P < 0.05). The net mean change in calcium retention was 212 mg/d during LP and 182 mg/d during EL. Several significant associations were found between the main outcome variables (%CaAbs, UCa, and markers of bone turnover) and serum hormones, especially IGF-I and PTH. Conclusions: Calcium homeostasis appears to be attained by a more efficient intestinal calcium absorption during pregnancy and by renal calcium conservation during both pregnancy and lactation. IGF-I and PTH seem to play major roles in the adjustment of calcium metabolism during pregnancy and lactation. KEY WORDS Pregnancy, lactation, calcium intake, calcium absorption, urinary calcium, calciotropic hormones, insulin-like growth factor I, Brazilian women

Hormone replacement therapy (HRT) in postmenopausal women does not appear to prevent a gain in fat and a loss of lean body tissue. A group of 118 women between 6 months and 6 years after menopause were randomly assigned to receive hormone replacement, calcium supplementation, or placebo. Women underwent annual dual photon absorptiometry, which measures the ratio of fat to total soft tissue, over the three-year trial. Women in the calcium group increased 12.5% in fat tissue mass per year, women in the HRT group increased 18.0% in fat tissue mass per year, and women in the placebo group increased 13.9% in fat tissue mass per year. They lost 5.6%, 7.4%, and 5.5% of lean tissue mass per year, respectively.

INSUFFICIENT dietary calcium (less than 800 mg/day) can raise the risk of calcium oxalate kidney stones. Less clear is how much calcium should be recommended to reduce the risk, which [...]

The risk for subsequent hip fractures in older women may be reduced with bone-active agents. The reduction in relative risks for hip fracture in women over 80 years old is 75%, 60%, 30% with estrogen therapy, calcium supplements, and calcitonin-salmon therapy, respectively. Combined calcium and calcitonin treatments resulted in a relative-risk reduction of 40% as compared to 30% when either drug is used alone. The reduction in the relative risks are also dependent on the length of treatments.