Calcium and zinc balances of premenopausal women consuming tofu-compared to cheese-containing diets

Abstract

A cross-over design was used to assess the effects of alternate 3-wk feedings of similar diets containing either 280 g tofu or 80 g cheese on calcium and zinc balance in 9 premenopausal women. The daily servings of cheese and tofu each accounted for approximately 58 and 28% of the total calcium and zinc, respectively, cotained in the experimental diets. A greater fecal calcium (p<0.05) and more negative calcium balance (p<0.05) was observed during the tofu compared to the cheese feeding period whereas zinc balance did not significantly differ between experimental diets. Since the cheese and tofu diets provided 1130 and 2100 mg of dietary phytate, respectively, the balance results are not consistent with the often reported negative effect of phytate on zinc absorption but support the possibility of a physiologically significant phytate/calcium interaction in the human gut.