ROLE OF SHORT-CHAIN FATTY-ACIDS IN THE PREVENTION OF COLORECTAL-CANCER

Short-chain fatty acids (SCFAs: acetate, propionate, n-butyrate) arisi ng in the large bowel during bacterial fermentation of dietary fibre a nd starch have paradoxical effects on colonic epithelial proliferation . While the three major SCFAs stimulate proliferation of normal crypt cells, n-butyrate and, to a lesser degree, propionate inhibit growth o f colon cancer cell lines. At the molecular level, n-butyrate causes h istone acetylation, favours differentiation, induces apoptosis and reg ulates the expression of various oncogenes. To understand the complex effects of SCFAs on carcinogenesis, it is important to study the inter mediate stages of the adenoma-carcinoma sequence where a ''switch'' fr om stimulation to suppression of cell proliferation must occur.