Folic acid and colorectal adenoma:
Folic acid (FA) supplementation (1 mg/d) in healthy individuals (aged 50 and older) may reduce the risk ratios of colorectal adenoma (CRA) or harmless growths in the colon. In this study, at the end of a 3-year follow-up period, 14.88% of participants taking FA had developed CRA, compared to 30.70% in the placebo group. Compared to placebo, the FA group had a 46% reduced risk ratio of left-side adenoma and 64% reduced risk ratio for advanced CRA. Additionally, participants with low levels of folate may be at higher risk of CRA. (21)
Vitamins A, C, and E decreased recurrence of colon cancers:
Antioxidant vitamins A, C, and E were found to lower the recurrence rate of cancers of the colon. Individuals (n=255) with a history of colonic adenoma were randomized to receive treatment with either (1) vitamin A (30,000 IU per day), vitamin C (1 gram per day), and vitamin E (70 mg per day); (2) lactulose; or (3) placebo for an average of 18 months. At the end of the treatment period, adenoma recurrence had occurred in 5.7% of the antioxidant vitamin group compared to 14.7% in the lactulose group and 35.9% in the placebo group. (22)