Calcium binding by dietary fibre.

Dietary fibre from plants low in phytate bound calcium in proportion to its uronic-acid content. This binding by the non-cellulosic fraction of fibre will reduce the availability of calcium for small-intestinal absorption, but the colonic microbial digestion of uronic acids will liberate the calcium. Thus the ability to maintain calcium balance on high-fibre diets may depend on the adaptive capacity of the colon for calcium absorption.