Vitamins May Reduce Risk of Colon Polyps

Vitamins May Reduce Risk of Colon Polyps

DIJON, France--Vitamins C, B6, Dand folate appear to reduce risk of colon adenoma in both smokers andnon-smokers, whereas beta carotene may only have a protective effect innon-smokers and an adverse effect in smokers, according to a study published inthe October issue of the Journal ofNutrition (135:2468-72, 2005).

French scientists investigated the effect of dietary vitamins andbeta-carotene on the risk of adenomas and a potential interaction with smokingstatus as part of a case-control study of environmental factors associated withthe risk of colorectal adenomas and cancers. The researchers compared nutrientintakes in polyp-free controls (n = 427) and adenoma cases (n = 362), globallyand using models stratified by smoking status, adjusted for age, sex, BMI, andenergy and alcohol intakes. Folate, vitamin C and vitamin B6 were inverselyrelated to adenoma risk, whereas vitamin D tended to be inversely associatedwith risk. There was a significant interaction between beta-carotene andsmoking. In nonsmokers, beta-carotene was inversely associated with adenomarisk, especially that of colon adenomas; whereas in past or current smokers,beta-carotene was not associated with a significant increase in the risk ofcolon adenomas.

The research findings support a chemoprotective effect of folate, vitamin Cand vitamin B6, irrespective of smoking habits, and a protective effect ofbeta-carotene in non-smokers only. Based on the adverse effect of beta-carotenein smokers, researchers concluded smokers should be cautious about taking highdoses of this micronutrient.