OK, so you already know that vitamin E can reduce your risk of prostate cancer. You may even be among the millions of people popping the vitamin in an attempt to stave off the disease, but what you may not know is that there are several forms of vitamin E and scientists are at odds about which form packs the greatest prevention punch. Vitamin E includes alpha, beta, gamma, and delta tocopherols. Now, results from a study published last year in the Journal of the National Cancer Institute sparked controversy about which tocopherol is responsible for disease prevention.

"What we've found is that the driving force for the preventive effect [on prostate cancer] is gamma tocopherol," says Karen Helzlsouer, Ph.D., at Johns Hopkins University Bloomberg School of Public Health in Baltimore and lead author of the study.

Historically alpha tocopherol has been the preferred form of vitamin E. In fact, when establishing the new dietary reference intakes, the Institute of Medicine specifically defined vitamin E as alpha tocopherol only, eliminating beta, gamma, and delta tocopherols.

Jeffrey Blumberg, Ph.D., chief of the Antioxidants Research Laboratory at Tufts University in Boston claims that the results of the new study should be interpreted loosely.

"It is in such marked contrast to what we know about vitamin E," says Blumberg. "The human body is designed to use alpha tocopherol. It recognizes the other forms, but the body preferentially transports the alpha."

What now?

"We should be careful not to assume that gamma tocopherol itself is the factor reducing risk until further studies are completed," says Maureen O'Ripple, Ph.D., research associate at Dartmouth College in Hanover, N.H., and prostate cancer expert. "This study provides strong evidence that gamma tocopherol levels are associated with decreased risk, but it has been far from proven that gamma tocopherol alone reduces risk."

Although the modern diet with soy and corn oils often consists of more gamma than alpha tocopherol, human levels of vitamin E are always higher in alpha than gamma. When scientists refer to a high level of gamma tocopherol, they are still talking about a concentration of gamma that is less than one-fifth that of alpha.

Even in the new study, the effect of gamma tocopherol was only seen when alpha or selenium, another powerful antioxidant, was also present.

"I'm as excited as anybody about finding nutritional solutions for prostate cancer," says Blumberg. "But if you say, 'New Study Finds Gamma in Favor of Alpha Tocopherol for the Prevention of Prostate Cancer,' that, in my opinion, is a wild and irresponsible leap to a conclusion."

Supplements: Supplant good diet?

Until this study, the nutrition community believed that alpha tocopherol, the form of vitamin E available in supplements, was the driving force behind disease prevention. In fact, most supplements on the market contain only alpha tocopherol. Now it seems that the only thing the experts agree on is that more research needs to be done.

Unfortunately the supplement industry is in the habit of taking findings from one study and marketing it to a public hungry for answers about disease prevention.

"If I were a manufacturer of gamma tocopherol supplements, I'd be jumping around dancing and trying to get every media outlet to pick up the story," claims Blumberg. "However, it's sufficiently premature and sufficiently insufficient: It's inconsistent with other observations."

The tricky thing about vitamin and mineral research is that all vitamins and minerals interact with each other and sometimes even inhibit one another.

"If you take alpha tocopherol you lower your gamma tocopherol levels," says Helzlsouer. "The important thing is don't just supplement yourself."

If people take supplements for their vitamin E without attending to dietary factors, they run the risk of not getting all forms of the vitamin, and thus not getting the most prevention bang for their buck!

The bottom line

Vitamin E is certainly not the only nutrient that has a preventive effect on prostate cancer. Studies show that selenium and carotenoids, such as beta-carotene and lycopene, also play a significant role in reducing risk. The best way to get these nutrients is by maintaining a diet high in fruits, vegetables -- especially dark-green leafy vegetables -- and whole grains.

"Most likely, one supplement such as gamma tocopherol is not going to be the answer to prostate cancer prevention," says O'Ripple. "A complete diet should be the goal for all of us."

All of the studies confirm one thing: A well-rounded diet not only ensures consumption of all forms of vitamin E but also provides the body with numerous other antioxidants that reduce the risk of cancer and improve general health.

"The encouraging thing is that there are ways to modify the risk," says Helzlsouer.