NEW YORK: A form of vitamin E not usually found in vitamin supplements may help protect against prostate cancer, researchers have found.

Recent studies have suggested certain antioxidants, including vitamin E, may fight prostate cancer. Antioxidants help protect cells from damage by mopping up substances called free radicals. The vitamin E most Americans get in supplements is called alpha-tocopherol. But now, research suggests that men with high blood levels of gamma-tocopherol, have a reduced risk for prostate cancer.

Among nearly 10,500 men who had blood samples collected in 1989, the 20% with the highest levels of gamma-tocopherol were five times less likely than men with the lowest levels of the vitamin to get prostate cancer over the next seven years.

Dr. Kathy J. Helzlsouer of the Johns Hopkins School of Public Health in Baltimore, Maryland, led the study. The findings are published in the December 20th issue of the Journal of the National Cancer Institute.

While alpha-tocopherol is the vitamin E of choice in supplements, food is the primary source of gamma-tocopherol among Americans. Vitamin E is found naturally in vegetable and seed oils, nuts, whole grains and leafy greens, but levels of the different forms of vitamin E vary.

For example, safflower oil contains mainly alpha-tocopherol, but soybean and corn oils contain more abundant supplies of gamma-tocopherol.

But the two forms of vitamin E do not perform strictly solo, according to the current study findings. Men with high levels of alpha-tocopherol and another antioxidant, selenium, were less likely to develop prostate cancer than were men with low concentrations of all three nutrients. Earlier work has shown that both alpha-tocopherol and selenium may reduce prostate cancer risk.

In this study, high levels of alpha-tocopherol and selenium were beneficial only when gamma-tocopherol was also high--suggesting gamma-tocopherol boosts the power of the other two antioxidants.

In an editorial accompanying the report, Dr. Edward Giovannucci of Harvard Medical School in Boston, Massachusetts calls the findings ``further reason for optimism'' that vitamin E and other compounds may fight prostate cancer.

However, he notes, vitamin E supplements--mainly alpha-tocopherol--can lower blood levels of gamma-tocopherol. According to Giovannucci, the average American's bloodstream is five times more rich in alpha-tocopherol than gamma-tocopherol. And, that difference jumps to 20-fold among people who take vitamin E supplements.

Since vitamin E supplements may displace gamma-tocopherol, Helzlsouer's team writes, future studies aimed at prostate cancer prevention should include both forms of vitamin E.

(From Reuters)