Ip. Vanmunster et al., EFFECT OF RESISTANT STARCH ON COLONIC FERMENTATION, BILE-ACID METABOLISM, AND MUCOSAL PROLIFERATION, Digestive diseases and sciences, 39(4), 1994, pp. 834-842
Resistant starch is by definition that part of starch that escapes dig
estion in the small bowel. Cecal fermentation of resistant starch into
short-chain fatty acids will result subsequently in a decrease in pH.
Thus, resistant starch may have the same effect on colonic luminal co
ntents and mucosa as some fiber components. We studied the effects of
adding 45 g native amylomaize (Hylon-VII) to a standardized diet in 14
healthy volunteers on fermentation and colonic mucosal proliferation.
Hylon-VII is a high amylose maize starch, containing 62% resistant st
arch. During amylomaize consumption, breath hydrogen excretion rose 85
% and fecal short chain fatty acid output increased 35% (P < 0.01). Ex
cretion of primaly bile acids increased and the soluble deoxycholic ac
id concentration decreased by 50% (P = 0.002). Subsequently, cytotoxic
ity of the aqueous phase of feces-as measured on a colon cancer cell l
ine-decreased (P = 0.007). Colonic mucosal proliferation in rectal bio
psies (proliferating cell nuclear antigen immunostaining) decreased fr
om 6.7 to 5.4% (P = 0.05). We speculate that resistant starch consumpt
ion decreases colonic mucosal proliferation as a result of the decreas
ed formation of cytotoxic secondary bile acids, which is possibly medi
ated through acidification of the large bowel by production of short-c
hain fatty acids.