Dietary soluble fiber and cholesterol
affect serum cholesterol concentration, hepatic portal venous
short-chain fatty acid concentrations and fecal sterol excretion
J Nutr. 1992 Feb;122(2):246-53.
Arjmandi BH, Ahn J, Nathani S, Reeves RD.
Department of Foods and Nutrition, Kansas State University, Manhattan
Sprague-Dawley rats were fed diets containing 7.5% dietary fiber
as cellulose (control), pectin, psyllium or oat bran with or without
0.3% added cholesterol for 3 wk. Among rats fed cholesterol, liver
total lipid and cholesterol concentrations were significantly
lower in groups fed pectin, psyllium and oat bran compared with
cellulose-fed controls. Cholesterol feeding resulted in significantly
greater liver cholesterol in rats fed cellulose, psyllium and
oat bran but not in those fed pectin. Among rats fed cholesterol,
total serum cholesterol levels were significantly lower in those
fed pectin than in those fed psyllium, oat bran or cellulose.
When cholesterol was fed, the oat bran-fed group had significantly
higher butyrate and the pectin-fed group had significantly higher
propionate concentrations in the hepatic portal vein than did
cellulose-fed controls. The groups fed psyllium, oat bran and
pectin all had significantly higher fecal neutral sterols than
did the cellulose-fed group when cholesterol was fed. Without
dietary cholesterol only pectin-fed rats had significantly higher
fecal excretion of neutral sterols than those fed cellulose. Dietary
fiber did not influence fecal acidic sterol excretion. However,
the addition of cholesterol to these fiber diets was accompanied
by a significantly higher bile acid excretion than that of animals
fed cellulose without cholesterol. The results of this study indicate
that soluble dietary fibers may exert their hypocholesterolemic
effect by increasing excretion of fecal neutral sterols.