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

• Published in: Nutrition and cancer Vol. 67; no. 1; pp. 73 - 81
• Main Authors: Li, Yiting, Sen, Ananda, Ren, Jianwei, Askew, Leah M, Sidahmed, Elkhansa, Brenner, Dean E, Ruffin, Mack T, Turgeon, D. Kim, Djuric, Zora
• Format: Journal Article
• Language: English
• Published: United States Routledge 02.01.2015
• Subjects: alpha-tocopherol; alpha-Tocopherol - blood; alpha-Tocopherol - metabolism; Biopsy; blood serum; colon; Colon - cytology; Colon - metabolism; Colon - pathology; Colonic Neoplasms - epidemiology; Colonic Neoplasms - metabolism; Colonic Neoplasms - pathology; Colonic Neoplasms - prevention & control; colorectal neoplasms; Diet; Diet, Mediterranean; Dietary Supplements; Female; food intake; foods; gamma-tocopherol; gamma-Tocopherol - blood; gamma-Tocopherol - metabolism; healthy diet; Healthy People Programs; Humans; Intestinal Mucosa - cytology; Intestinal Mucosa - metabolism; Intestinal Mucosa - pathology; Male; Michigan - epidemiology; Middle Aged; Nutrition Policy; nuts; Olea; olive oil; Patient Dropouts; people; Risk; Vitamin E - metabolism; Vitamin E - therapeutic use; Michigan; MED
• ISSN: 1532-7914; 0163-5581; 1532-7914
• DOI: 10.1080/01635581.2015.965333

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.