In Vivo Mineral Contents of Dietary Fiber Determined by EDX Analysis

In the past fifteen years there has been extensive research into relationships between the dietary fiber content of human and animal diets and health and nutrition. A continuing concern is that binding of minerals to dietary fiber may impair mineral bioavailability (Kies, 1985; Sandstrom et al., 1987). The in vitro binding of elements such as Ca, Fe, Mg, and Zn to various fiber substrates has been reported (Camire & Clydesdale, 1981; Reinhold et al., 1981). Numerous feeding studies in recent literature (reviewed by Kelsay, 1986) also address questions of effects on mineral bioavailability of dietary fiber in human and animal diets. An interesting question is whether or not the plant cell walls of the dietary fiber source impede mineral absorption by acting as mineral sinks that remove significant amounts of cations from the intestinal lumen. However, there are relatively few studies that examine changes in the mineral content of such tissues to directly measure in vivo mineral binding.