Am. Stephen, WHOLE GRAINS - IMPACT OF CONSUMING WHOLE GRAINS ON PHYSIOLOGICAL-EFFECTS OF DIETARY FIBER AND STARCH, Critical reviews in food science and nutrition, 34(5-6), 1994, pp. 499-511
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.