TY - JOUR
T1 - Effects of vitamin E from supplements and diet on colonic α-and γ-tocopherol concentrations in persons at increased colon cancer risk
AU - Li, Yiting
AU - Sen, Ananda
AU - Ren, Jianwei
AU - Askew, Leah M.
AU - Sidahmed, Elkhansa
AU - Brenner, Dean E.
AU - Ruffin, Mack T.
AU - Turgeon, D. Kim
AU - Djuric, Zora
N1 - Publisher Copyright:
© 2015 Taylor & Francis Group, LLC.
PY - 2015/1/2
Y1 - 2015/1/2
N2 - 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.
AB - 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.
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U2 - 10.1080/01635581.2015.965333
DO - 10.1080/01635581.2015.965333
M3 - Article
C2 - 25372556
AN - SCOPUS:84920535742
SN - 0163-5581
VL - 67
SP - 73
EP - 81
JO - Nutrition and cancer
JF - Nutrition and cancer
IS - 1
ER -