ISMNT News #51. A high fiber intake is associated with a reduced incidence

of colon cancer. During fiber fermentation in the gut, butyric acid is

formed in large amounts which can induce death by apoptosis in colon cancer

cells. Cancer cells should go into apoptosis but are resistant to this

self-programmed death. In a study by Archer et al.(Proc Natl Acad Sci U S A

1998 Jun 9;95(12):6791-6796) it is shown that butyrate induces p21 mRNA

expression which appears as important molecular link between a high-fiber

diet and the prevention of colon carcinogenesis.

The key reference is by:

Smith JG, Yokoyama WH, German JB

Department of Food Science and Technology, University of California, Davis

Butyric acid from the diet: actions at the level of gene expression

Crit Rev Food Sci Nutr 1998 May;38(4):259-297

A number of components present in the diet, although nutritionally

nonessential, have been discovered to have beneficial effects toward both

general health and disease prevention/protection. One such nutrient, butyric

acid, can be derived in large quantities from bacterial fementation of

dietary fiber in the bowel and is also a component of bovine milk.

In gut fermentation, the production of butyric acid defines its delivery

point; thus, the synthesis and site of action of butyric acid are in close

proximity and have frustrated the investigation of its activities in vivo.

Recent research has, however, revealed a number of activities of butyric

acid toward isolated cells. In particular, its ability to modify nuclear

architecture and induce death by apoptosis in colon cancer cells is arousing

great interest. Butyric acid changes the structure of chromatin through its

effects on posttranslational modifications, key modifications being

acetylation and phosphorylation of the nuclear histones. Butyric acid can

also modify the differentiation state of cells, and in the case of cancerous

colonic cells overcomes their resistance to normal programmed death.

Thus, the activities of this fermentation product of dietary fiber may

contribute substantially to the decreased incidence of bowel cancer that has

been associated with fiber intake.