Prostate Cancer prevention
Orthodox medical research is now coming up with strong evidence supporting the taking of certain supplements and eating particular foods to prevent and slow down the progress of prostate cancer. This article looks at Vitamin E, Selenium, Genistein and Lycopene.
Vitamin E is an essential vitamin with a recommended dietary intake of 15 mg per day for adults though doses of over 1000 mg per day have been shown to have no ill effects. Vitamin E is actually a general name for a group of compounds called tocopherols. Typically, oral supplements of vitamin E are given in the alpha-tocopherol form.
Vitamin E has potent anti-oxidant properties and may also protect against cancer by enhancing immune functions, lowering the activity of protein kinase C (involved in regulating the proliferation of cells) and inducing apoptosis (programmed cell death) . This vitamin has been shown to inhibit the growth of prostate cancer cells in tissue culture.
The most convincing study on the role of Vitamin E in prostate cancer was the Alpha-tocopherol, Beta-carotene Cancer prevention trial. In this study Finnish male smokers receiving 50 mg of Vitamin E per day had a 33% reduction in prostate cancer incidence and a 41% reduction in prostate cancer mortality. This group experienced a reduction in clinically detectable prostate cancer within 2 years of taking the supplement.
Note: Vitamin E should not be take in high doses when also on strong anti-clotting agents like Warfarin or heparin.
Selenium, this is an essential trace element for humans found in grains, fish and meats but with the highest levels in brazil nuts. Large variations exists in dietary selenium consumption across the population because the availability of selenium depends critically on selenium concentrations in the soil.
Higher selenium levels were found to be associated with a reduced risk of prostate cancer as determined by serum selenium concentrations, measure of short term selenium intake, or amount of selenium in toenail clippings which is a surrogate marker for long term selenium intake.
Selenium at different doses may affect several types of anti-carcinogenic activities, including anti-oxidant protection, carcinogen metabolism, immune enhancement and apoptosis (death of cancer cells). Selenium works synergistically with Vitamin E to prevent cancer developing and Vitamin E reduces the oxidative damage seen in selenium deficiency.
The most profound evidence of protective effect of selenium on prostate cancer so far has been a double blind placebo controlled trial in which 1,312 patients with a history of skin cancer were randomised to take either a placebo or a daily dose of 200 micrograms of selenium for 4 to 5 years. Although researchers failed to detect the protective effect of selenium on skin cancer, the risk of prostate cancer rate was found to be reduced by two thirds of that of the men receiving the placebo.
Genistein found in soy products and Lycopene found principally in tomatoes have also been shown to be protective against prostate cancer. The studies which show this are mainly those linking diet with prostate cancer incidence. However, other studies have shown that these substances inhibit the growth prostate cancer cells in tissue culture.
Extracted from an article by E. W. Woo et al in the November/December issue of Oncology Issues
Colin Sutherland (July 2001)