Glucomannan Curbs Colon Cancer Risk

TAICHUNG, TaiwanColon cancer induced by a high-fat diet may be curtailed by glucomannan, a polysaccharide from the konjac plant, according to new study results published online ahead of print Jan. 5 in the Journal of Agricultural and Food Chemistry. Researchers from Chung Shan Medical University studied the effects of konjac glucomannan in a high-fat corn oil diet on risk factors of colon carcinogenesis, including fecal -glucuronidase, mucinase, and bile acids, as well as on preventive factors such as fecal microflora and cecal (pertaining to the first section of the large bowel) short-chain fatty acids (SCFAs).

Sprague-Dawley rats (n = 8 animals per group) were fed a normal-fat/fiber-free (5 percent corn oil, weight in weight) or high-fat/fiber-free  (25 percent corn oil, w/w) diet, glucomannan (5 percent, w/w), or inulin (5 percent, w/w, as a prebiotic control) for four weeks. Researchers found  the high-fat, fiber-free diet significantly elevated the fecal -glucuronidase and mucinase activities and total bile acid concentration, while decreasing cecal SCFA contents, as compared with the normal-fat/fiber-free diet.  However, adding glucomannan or inulin into the high-fat diet beneficially reduced the fecal -glucuronidase and mucinase activities as well as  lithocholic acid (secondary bile acid) concentration. Glucomannan elevated the daily fecal total bile acid excretion, but researchers attributed the change to the primary, instead of the secondary, bile acids. Further, glucomannan beneficially promoted the daily fecal excretion of bifidobacteria and lactobacilli as well as cecal SCFA contents, as compared with the high-fat fiber-free diet. They concluded konjac glucomannan potentially attenuated the high fat-induced risk in colon carcinogenesis.