Dataset Information

Effects of vitamin E from supplements and diet on colonic ?- and ?-tocopherol concentrations in persons at increased colon cancer risk.

ABSTRACT: The available evidence indicates that ?-tocopherol has more potential for colon cancer prevention than ?-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 ?-tocopherol at baseline was positively predicted by dietary intakes of synthetic vitamin E in foods and supplements but not by natural ?-tocopherol from foods. For serum ?-tocopherol, dietary ?-tocopherol was not a predictor, but dietary ?-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 ?- and ?-tocopherol in colon. The Mediterranean intervention increased intakes of natural ?-tocopherol, which is high in nuts, and decreased intakes of ?-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.

SUBMITTER: Li Y

PROVIDER: S-EPMC4281489 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Effects of vitamin E from supplements and diet on colonic α- and γ-tocopherol concentrations in persons at increased colon cancer risk.

Li Yiting Y Sen Ananda A Ren Jianwei J Askew Leah M LM Sidahmed Elkhansa E Brenner Dean E DE Ruffin Mack T MT Turgeon D Kim DK Djuric Zora Z

Nutrition and cancer 20141105 1

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 bas ...[more]

PMID: 25372556

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Project description:Introduction There is no consensus for the optimum concentration of vitamin D, although a minimum concentration of 100 ng/mL (250 nM) of circulating vitamin D, measured as 25(OH) D, has been suggested in order to support optimal health in dogs. Few studies have examined the relationship between dietary vitamin D3 (cholecalciferol) intake and the resulting concentrations of circulating 25(OH) D in adult dogs. Recommendations for dog foods for adult maintenance report a safe upper limit of 3,200 IU vitamin D/kg on a dry matter basis. However, these recommendations were not based on studies of adult maintenance requirements. Understanding the relationship between dietary vitamin D and circulating vitamin D is necessary to utilize dietary vitamin D to influence health in dogs. Methods Five groups of adult dogs (each n = 8) were fed food of approximately 4,000 kcal/kg containing one of the following dry matter concentrations of vitamin D for 6 months: 795.7, 3087.3, 5510.9, 7314.0, and 9992.5 IU/kg. Body weight was recorded at baseline and measured weekly, and daily food intake was recorded. Blood samples were taken at baseline and at the end of the 26-week study period. Results There were no clinical signs of vitamin D deficiency or excess. Serum concentrations of creatinine, blood urea nitrogen, albumin, hematocrit, hemoglobin, alkaline phosphatase, phosphorus, total calcium, ionized calcium, and parathyroid hormone were maintained within reference values in all groups. Circulating 25(OH) D increased in all groups except those that consumed food with 795.7 IU/kg vitamin D, and increased in a linear and quadratic fashion in response to dietary vitamin D concentration. All of the dogs fed food with 5510.9 IU/kg vitamin D or above met or exceeded 100 ng/mL (250 nM) circulating 25(OH) D. Discussion Dietary vitamin D was positively associated with increased circulating concentrations in concentrations up to 9992.5 IU/kg dry matter, with no observable adverse effects. Consumption of ≥5510.9 IU/kg vitamin D resulted in all dogs with at least the 100 ng/mL (250 nM) circulating concentration.

Project description:BackgroundVitamin E compounds exhibit prostate cancer preventive properties experimentally, but serologic investigations of tocopherols, and randomized controlled trials of supplementation in particular, have been inconsistent. Many studies suggest protective effects among smokers and for aggressive prostate cancer, however.MethodsWe conducted a nested case-control study of serum ?-tocopherol and ?-tocopherol and prostate cancer risk in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, with 680 prostate cancer cases and 824 frequency-matched controls. Multivariate-adjusted, conditional logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CIs) for tocopherol quintiles.ResultsSerum ?-tocopherol and ?-tocopherol were inversely correlated (r?=?-0.24, p<0.0001). Higher serum ?-tocopherol was associated with significantly lower prostate cancer risk (OR for the highest vs. lowest quintile?=?0.63, 95% CI 0.44-0.92, p-trend 0.05). By contrast, risk was non-significantly elevated among men with higher ?-tocopherol concentrations (OR for the highest vs. lowest quintile?=?1.35, 95% CI 0.92-1.97, p-trend 0.41). The inverse association between prostate cancer and ?-tocopherol was restricted to current and recently former smokers, but was only slightly stronger for aggressive disease. By contrast, the increased risk for higher ?-tocopherol was more pronounced for less aggressive cancers.ConclusionsOur findings indicate higher ?-tocopherol status is associated with decreased risk of developing prostate cancer, particularly among smokers. Although two recent controlled trials did not substantiate an earlier finding of lower prostate cancer incidence and mortality in response to supplementation with a relatively low dose of ?-tocopherol, higher ?-tocopherol status may be beneficial with respect to prostate cancer risk among smokers. Determining what stage of prostate cancer development is impacted by vitamin E, the underlying mechanisms, and how smoking modifies the association, is needed for a more complete understanding of the vitamin E-prostate cancer relation.

Dataset Information

Effects of vitamin E from supplements and diet on colonic ?- and ?-tocopherol concentrations in persons at increased colon cancer risk.

Publications

Effects of vitamin E from supplements and diet on colonic α- and γ-tocopherol concentrations in persons at increased colon cancer risk.

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