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The addition of milk and milk-based products to the diets of individuals subsisting on plant-based diets was reported to have positive effects on nutritional status and functional outcomes such as growth, morbidity, and cognition. We examined the effect of the addition of milk or yogurt on the bioavailability of zinc and iron from a plant-based rural diet. The subjects were 48 Mexican women (30.9 +/- 5.7 y) who habitually consumed a plant-based diet. The women were assigned to 1 of 3 groups: 1) the typical rural Mexican diet, 2) that diet with milk added, or 3) that diet with yogurt for 13 d. Zinc absorption was measured after extrinsically labeling meals with (67)Zn and an i.v. dose of (70)Zn; iron absorption was measured by extrinsically labeling meals with (58)Fe and a reference oral dose of (57)Fe. Including milk and yogurt in the diet increased zinc absorption by 50 and 68%, respectively (P < 0.05). The 3 groups did not differ in the percentage iron absorption. The total amount of zinc absorbed was increased (P < 0.05) by 70% when milk was added to the meal and 78% when yogurt was added. The total amount of iron absorbed did not differ among the groups. The addition of milk and yogurt to a plant-based diet high in phytate increases zinc bioavailability without affecting iron bioavailability. [ABSTRACT FROM AUTHOR]

Provision of the bone minerals and vitamin D as fortificants in food or as dietary supplements designed for older infants and toddlers in Latin America is likely to be beneficial and safe. Currently available data are inadequate to establish the precise amounts of these nutrients that would be required for such a supplement. These amounts would vary according to the local base diet. However, reasonable estimates can be made on the basis of current dietary recommendations as well as existing data on bioavailability and customary intake. The strongest case can be made for calcium and vitamin D supplementation. Because excessive dietary calcium can reduce zinc absorption as a result of interactive effects within the intestine, an appropriate ratio of calcium to zinc should be used, even if this means adding zinc as a fortificant or supplement. Magnesium supplementation may be appropriate in some circumstances but it cannot be routinely advocated at present. It is unlikely that phosphorus supplementation is needed for most population groups because of the relatively high usual dietary phosphorus intakes, primarily from phosphate salts added to carbonated beverages and as food preservatives. [ABSTRACT FROM AUTHOR]

To assess the possibility of ethnic differences in mineral metabolism in prepubertal children, we compared measures of calcium metabolism in 7- and 8-y-old Mexican-American (MA) and non-Hispanic Caucasian (CAU) girls (n = 38) living in southeastern Texas. We found similar fractional calcium absorption, urinary calcium excretion, calcium kinetic values and total-body bone mineral content in the MA and CAU girls. In contrast, parathyroid hormone (PTH) concentrations were greater in MA girls (4.01 +/- 0.47 vs. 1. 96 +/- 0.50 pmol/L, P = 0.005) than in CAU girls. Serum 25-hydroxyvitamin D concentrations were lower in MA girls (68.9 +/- 7.7 vs. 109.4 +/- 8.4 nmol/L, P = 0.001) than in CAU girls, but 1, 25-dihydroxyvitamin D concentrations did not differ between groups. Seasonal variability was seen for 25-hydroxyvitamin D concentrations in girls of both ethnic groups, but values in all of the girls were >30 nmol/L (12 ng/mL). We conclude the following: 1) greater PTH levels in MA girls than CAU girls are present without evidence of vitamin D deficiency; and 2) differences in 25-hydroxyvitamin D and PTH concentrations between MA and CAU girls do not have a large effect on calcium absorption, excretion or bone calcium kinetics. These data do not provide evidence for adjusting dietary recommendations for mineral or vitamin D intake by MA girls. [ABSTRACT FROM AUTHOR]

The major components of calcium metabolism, as evaluated by a dual-tracer stable isotope method, were determined in 100 studies of 68 healthy girls, aged 5-18 y and analyzed from a developmental and regulatory viewpoint. Bone calcium deposition and removal rates were closely correlated with the size of the exchangeable bone calcium compartment. All three quantities, as well as intestinal calcium absorption, peaked at or near menarche. Both bone calcium deposition and removal rates were positively and linearly correlated with calcium absorption. However, in this correlation, because bone calcium deposition increased 70% faster than calcium absorption, most of the increase in the bone calcium compartment and its turnover must have occurred in response to something other than intestinal calcium input; presumably this occurred in response to developmental signals. Nevertheless, the constancy of the serum calcium in the face of a large intestinal calcium input and the modest way in which excretion overcame the calcium load in this population point to the importance of the exchangeable bone calcium compartment, in dynamic equilibrium with the bone mineral, as the site at which most of the load is taken up. In this population of girls, as in older women, this increase in the skeletal calcium balance resulted from a decrease in the bone calcium removal rate that was greater than the corresponding increase in the bone calcium deposition rate. [ABSTRACT FROM AUTHOR]