n-3 PUFA and alpha-tocopherol control of tumor cell proliferation.

Subjects at high risk for colon cancer received different doses of fish oil on a 30-day randomized double-blind trial to evaluate the chemopreventive effect of n-3 fatty acids against colorectal cancer. Using rectal mucosal proliferation, assessed with 3H-thymidine autoradiography, fish oil induced in the treated groups but not in the placebo group a change in the proliferative pattern, which resulted similar to that observed in low risk population; in the same groups rectal mucosal n-3 fatty acid content increased, where arachidonic acid level decreased. Moreover, n-3 PUFA treatment induced modifications of Vitamin E status. The results suggest that n-3 PUFA could protect high-risk subjects from colon cancer by a mechanism involving a modulation of Vitamin E.