WHOLE GRAINS - IMPACT OF CONSUMING WHOLE GRAINS ON PHYSIOLOGICAL-EFFECTS OF DIETARY FIBER AND STARCH

Much of the present research on the physiological effects of dietary f iber and starch has been done on sources isolated from the parent mate rial, and it is not clear whether they have the same effects if fed in the intact or whole grain. For dietary fiber, physiological effect de pends on extent of fermentation in the large intestine, and this is in fluenced by chemical composition, solubility, physical form, and prese nce of lignin or other compounds. All of these factors are altered by isolation of a fiber source from the whole grain, and hence effects of eating fiber vary. Similarly, physical form and presence in the whole grain will affect digestibility of starch in the small intestine, whi ch in turn influences the glycemic response and colonic effects determ ined by the extent of malabsorption and entry into the colon. Starch t hat enters the colon is fermented and produces short-chain fatty acids , particularly butyrate, which is necessary to maintain a healthy muco sa. Hence, their presence within the whole grain may have important im plications for health for both dietary fiber and starch. Evidence indi cates that such effects are beneficial and that whole-grain consumptio n should be encouraged.