Effects of Vitamin E From Supplements and Diet on Colonic α- and γ-tocopherol Concentrations in Persons at Increased Colon Cancer Risk.

Auteur(s) :
Barendregt J., Sen A., Djuric Z., Li Y., Askew LM., Sidahmed E., Brenner DE., Ruffin MT., Turgeon DK.
Date :
Nov, 2014
Source(s) :
Nutr Cancer.. #: p1-9
Adresse :
Department of Family Medicine , University of Michigan , Ann Arbor , Michigan , USA. zoralong@umich.edu

Sommaire de l'article

The available evidence indicates that γ-tocopherol has more potential for colon cancer prevention than α-tocopherol, but little is known about the effects of foods and supplements on tocopherol levels in human colon. This study randomized 120 subjects at increased colon cancer risk to either a Mediterranean or a Healthy Eating diet for 6 mo. Supplement use was reported by 39% of the subjects, and vitamin E intake from supplements was twofold higher than that from foods. Serum α-tocopherol at baseline was positively predicted by dietary intakes of synthetic vitamin E in foods and supplements but not by natural α-tocopherol from foods. For serum γ-tocopherol, dietary γ-tocopherol was not a predictor, but dietary α-tocopherol was a negative predictor. Unlike with serum, the data supported a role for metabolic factors, and not a direct effect of diet, in governing concentrations of both α- and γ-tocopherol in colon. The Mediterranean intervention increased intakes of natural α-tocopherol, which is high in nuts, and decreased intakes of γ-tocopherol, which is low in olive oil. These dietary changes had no significant effects on colon tocopherols. The impact of diet on colon tocopherols therefore appears to be limited.

Source : Pubmed