Vitamin E +/- supplement vs prostate cancer?

[Guest guest]

Is it the supplements, the diets or the blood levels of different vitamin forms that may protect us from prostate cancer? For the (2) paper,what was the reason that supplementing alpha or beta form of tocopherol resulted in less cancer? Both studies are prospective, but that of the (2) paper appears to confirm earlier studies using a shorter prospective time. 1. ME, Weinstein SJ, Lawson KA, Albanes D, Subar AF, Dixon LB, Mouw T, Schatzkin A, Leitzmann MF.Supplemental and dietary vitamin e intakes and risk of prostate cancer in a large prospective study.Cancer Epidemiol Biomarkers Prev. 2007 Jun;16(6):1128-35. PMID: 17548674 Supplemental vitamin E (alpha-tocopherol) has been linked to lower prostate cancer

incidence in one randomized trial and several, although not all, observational studies. The evidence regarding dietary intake of individual vitamin E isoforms and prostate cancer is limited and inconclusive, however. We prospectively examined the relations of supplemental vitamin E and dietary intakes of alpha-, beta-, gamma-, and delta- tocopherols to prostate cancer risk among 295,344 men, ages 50 to 71 years and cancer-free at enrollment in 1995 to 1996, in the NIH-AARP Diet and Health Study. At baseline, participants completed a questionnaire that captured information on diet, supplement use, and other factors. Proportional hazards models were used to estimate relative risks (RR) and 95% confidence intervals (95% CI) of prostate cancer. During 5 years of follow-up, 10,241 incident prostate cancers were identified. Supplemental vitamin E intake was not related to prostate cancer risk (for >0-99, 100-199, 200-399, 400-799, and >/=800 IU/d versus never use: RR,

0.97, 0.89, 1.03, 0.99, and 0.97 (95% CI, 0.87-1.07) respectively; P(trend) = 0.90). However, dietary gamma-tocopherol, the most commonly consumed form of vitamin E in the United States, was significantly inversely related to the risk of advanced prostate cancer (for highest versus lowest quintile: RR, 0.68; 95% CI, 0.56-0.84; P(trend) = 0.001). These results suggest that supplemental vitamin E does not protect against prostate cancer, but that increased consumption of gamma-tocopherol from foods is associated with a reduced risk of clinically relevant disease. The potential benefit of gamma-tocopherol for prostate cancer prevention deserves further attention. 2. Weinstein SJ, ME, Lawson KA, Snyder K, Mannisto S, PR, Virtamo J, Albanes D.Serum and dietary vitamin e in relation to prostate cancer risk.Cancer Epidemiol Biomarkers Prev. 2007 Jun;16(6):1253-9. PMID: 17548693 alpha-Tocopherol supplementation (50 mg daily for 5-8 years) reduced prostate cancer incidence by 32% in the alpha-Tocopherol, beta-Carotene Cancer Prevention Study. We investigated whether serum alpha-tocopherol or intake of vitamin E (eight tocopherols and tocotrienols) was associated with prostate cancer risk with up to 19 years of follow-up in the alpha-Tocopherol, beta-Carotene Cancer Prevention Study cohort. Of the 29,133 Finnish male smokers, ages 50 to 69 years recruited into the study, 1,732 were diagnosed with incident prostate cancer between 1985 and 2004. Baseline serum alpha-tocopherol was measured by high-performance liquid chromatography and the components of vitamin E intake were estimated based on a 276-item food frequency questionnaire and food chemistry analyses. Proportional hazard models were used to determine multivariate-adjusted relative risks (RR) and 95% confidence intervals (95% CI). Higher serum

alpha-tocopherol was associated with reduced risk of prostate cancer (RR, 0.80; 95% CI, 0.66-0.96 for highest versus lowest quintile; P(trend) = 0.03) and was strongly and inversely related to the risk of developing advanced disease (RR, 0.56; 95% CI, 0.36-0.85; P(trend) = 0.002). The inverse serum alpha-tocopherol-prostate cancer association was greater among those who were supplemented with either alpha-tocopherol or beta-carotene during the trial. There were no associations between prostate cancer and the individual dietary tocopherols and tocotrienols. In summary, higher prediagnostic serum concentrations of alpha-tocopherol, but not dietary vitamin E, was associated with lower risk of developing prostate cancer, particularly advanced prostate cancer. -- Al Pater, alpater@...

Take the Internet to Go: Go puts the Internet in your pocket: mail, news, photos more.