Objectives
•Appreciate how fiber can be used in the management and prevention of disease
•Diabetes
•Heart disease
•GI disorders
•Cancers
•High bile acid concentrations are associated with a high risk
of colon cancer. Thus, fibers that adsorb bile acids to promote
fecal excretion serve a protective effect.
•Fibers that increase fecal bulk decrease the intraluminal
concentrations of carcinogens and thereby reduce the
likelihood of interactions with colonic mucosal cells.
•Allowance of a fermentable substrate to colonic bacteria
alters kinds and numbers of bacteria and/or their metabolism,
which may inhibit proliferation or development of tumor cells or
conversion of procarinogens to carcinogens.
•A shortened fecal transit time decreases the time during which
toxins can be synthesized and in which they are in contact with
the colon.
•Fiber fermentation to short-chain fatty acids decreases the
interluminal pH, thereby decreasing synthesis of secondary
bile acids, which have been shown to promote the generation
of tumors.
•Degradation of fiber by fermentation may release fiber-bound
calcium. The increased calcium in the colon may help eliminate
the mitogenic advantage that cancer cells have over normal
cells in a low-calcium environment.
•Butyric acid appears to slow the proliferation and
differentiation of colon cancer cells.
•Insoluble fibers such as lignin that resist degradation bind
carcinogens, thereby minimizing the chances of interactions
with colonic mucosal cells.
