Effects of vitamin E from supplements and diet on colonic α- and γ-tocopherol concentrations in persons at increased colon cancer risk.
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.
a Department of Family Medicine , University of Michigan , Ann Arbor , Michigan , USA.
Yiting
Y
Li
Ananda
A
Sen
Jianwei
J
Ren
Leah M
LM
Askew
Elkhansa
E
Sidahmed
Dean E
DE
Brenner
Mack T
MT
Ruffin
D Kim
DK
Turgeon
Zora
Z
Djuric
D001706:Biopsy; D003106:Colon / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D003110:Colonic Neoplasms / Q000453:epidemiology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D004032:Diet; D038441:Diet, Mediterranean; D019587:Dietary Supplements; D005260:Female; D040361:Healthy People Programs; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008824:Michigan / Q000453:epidemiology; D008875:Middle Aged; D018673:Nutrition Policy; D010352:Patient Dropouts; D012306:Risk; D014810:Vitamin E / Q000378:metabolism* / Q000627:therapeutic use; D024502:alpha-Tocopherol / Q000097:blood / Q000378:metabolism*; D024504:gamma-Tocopherol / Q000097:blood / Q000378:metabolism*
D014810:Vitamin E; D024504:gamma-Tocopherol; D024502:alpha-Tocopherol