Other News

Is Vitamin C a Pro-oxidant?

A study just published in the British journal Nature and widely reported in the media claims that supplementation of humans with 500 mg of vitamin C per day causes increased oxidative damage to the DNA in lymphocytes, as measured by 8-oxoadenine. The same study shows a decrease in another oxidative DNA damage product, 8-oxoguanine. While the latter is an established marker of oxidative DNA damage, the former is not. In addition, 8-oxoguanine has been reported to be at least ten times less mutagenic, and thus less biologically harmful, than 8-oxoguanine. Furthermore, another British study has found that supplementation with 14 mg of iron and 60 or 260 mg of vitamin C per day causes a 75% decrease in lymphocyte 8-oxoadenine levels. Thus, the evidence with respect to 8-oxoadenine is inconsistent, and its validity as a marker of oxidative damage as well as its biological significance are unclear. The totality of scientific evidence overwhelmingly shows antioxidant and beneficial effects of vitamin C, not pro-oxidant effects. Don't stop taking your vitamin C!

Remarkable Anticancer Role of Vitamin E

The results of a cancer prevention study in Finland support a protective role for vitamin E against prostate cancer. Published in March in the Journal of the National Cancer Institute, the study followed over 29,000 men for five to eight years. Daily supplemental doses of about 50 International Units of vitamin E dramatically reduced the diagnosis (by 32% compared to men who didn't take vitamin E) and mortality (by 41%) of prostate cancer, possibly by blocking the conversion of subclinical cancer to aggressive disease. For more information on the biological role of vitamin E, please see Dr. Maret Traber's article in this Newsletter.

Last updated May, 1998

Honoring a Scientific Giant with Research Toward Longer, Better Lives

Please send any comments, suggestions, or questions about The Linus Pauling Institute to lpi@oregonstate.edu