Bread (white and whole wheat) and nonfat dry milk as sources of bioavailable calcium for rats.

These studies examined the bioavailability of calcium in bread (white and whole wheat) and nonfat dry milk. Most of the calcium in breads originated from nonwheat sources such as yeast food, milk replacer (a whey-soy blend) and calcium propionate. Bioavailabilities were calculated by the slope ratio technique. Slopes were determined using increases (over calcium-free diet) in femur calcium content of rats fed calcium-containing diets plotted against their actual calcium intakes as the test criterion. Compared to calcium in calcium sulfate (considered as 100%), the bioavailability of calcium in milk was 113.3%, and that in white and whole wheat bread 99.4% and 104.4% respectively. Thus, calcium in bread appears readily available, but still somewhat less than that in milk.