Selenium and Prostate Cancer

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Hi folks:

Not sure if this has been posted before or not. But just in case:

" Selenium and prostate cancer risk

BOSTON, MASSACHUSETTS. At least five major clinical trials have

concluded that higher levels of selenium (in blood or toenail

clippings) are associated with a sharply reduced risk of prostate

cancer. The Nutritional Prevention of Cancer (NPC) trial found that

supplementing with 200 micrograms/day of selenium cuts prostate

cancer risk in half. Researchers at the Harvard Medical School now

weigh in with another study confirming the beneficial effects of

selenium. Their study involved 22,000 healthy, male physicians who

were enrolled in the study in 1982 and had blood samples taken at

that time. Sufficient samples to analyze for selenium content and PSA

level were available for 586 men diagnosed with prostate cancer as

well as for 577 controls matched for age and smoking status.

After 13 years of follow-up the researchers concluded that study

participants with a plasma selenium level of 0.12-0.19 ppm had a 50%

lower incidence of advanced prostate cancer than did men with a level

of 0.06-0.09 ppm. The correlation was only apparent in men with a PSA

level of more than 4 ng/mL and was particularly strong for those with

a baseline (1982) PSA level greater than 10 ng/mL. For these men a

high selenium level corresponded to a 70% decrease in the risk of

advanced prostate cancer. The researchers also observed a trend for a

lower incidence of localized prostate cancer with high selenium

levels, but this trend was not statistically significant. They

conclude that selenium is perhaps not too effective in preventing the

initiation of prostate cancer, but that it is highly effective in

slowing down tumor progression. They believe that selenium acts by

selectively killing off cells whose DNA has been extensively damaged,

by inhibiting cellular proliferation, and by its role as a key

component of glutathione peroxidase, which protects cells from

peroxide damage.

Li, H, et al. A prospective study of plasma selenium levels and

prostate cancer risk. Journal of the National Cancer Institute, Vol.

96, May 5, 2004, pp. 696-703

, PR, et al. Science peels the onion of selenium effects on

prostate carcinogenesis. Journal of the National Cancer Institute,

Vol. 96, May 5, 2004, pp. 645-47 (editorial)

Editor's comment: The evidence is now indeed overwhelming that

selenium helps protect against prostate cancer. While this study

concluded that the protection mainly involves slowing down tumor

progression, other studies have shown that selenium also helps

prevent initiation of the cancer. Thus daily supplementation with 200

micrograms of selenium should be an integral part of all

supplementation programs for men. "

Rodney.