So far studies with Vitamin E have not been beneficial (go here.) The vitamin E and selenium study (SELECT) trial was stopped early (go here). A study of Vitamin C and E showed no value (go here).

A recent study suggested drinking pomegranate juice (go here).

Other preventive advice from Rakel: Integrative Medicine, 1st ed., Copyright © 2003 Elsevier:
Encourage exercise for 30 minutes or longer at least three times weekly.
• Avoid hormone-altering medications such as DHEA, androstenedione, human growth hormone, and testosterone, unless medically indicated.
• Instruct patients to buy organic produce whenever possible. Wash all produce and peel when applicable. Drink filtered water, and cook and store food in glass containers.
• Advise patients to reduce or eliminate dairy and meat consumption.
• Instruct patients to use olive or canola oil instead of other vegetable oils.
• Emphasize that patients should avoid tobacco products and excessive alcohol consumption.

Advice from Andrew Weil (caveat emptor!) is noted below

Fighting Off Prostate Cancer
Prostate cancer is the second most common cause of cancer deaths in men. Scientists have estimated that lifestyle factors account for about 75 percent of advanced prostate cancer cases. Of all the environmental factors, diet appears to be the most influential. So what can you do about prostate cancer? Try the following:

• Watch your diet. Avoid a diet high in red meat, saturated fat and dairy products, all of which may increase the risk for prostate cancer. Instead, eat more tomatoes, especially tomatoes in sauces -- they contain lycopene, a carotenoid linked to a lower risk of prostate cancer. Also include soy foods, which contain genistein, an isoflavone that helps normalize hormone levels; fish, which may lower the risk of prostate cancer; and fiber -- which helps flush hormones, such as testosterone and estrogen, out of the body.
• Drink green tea. An antioxidant compound in green tea called EGCG kills prostate cancer cells in lab studies. Another compound in green tea blocks the actions of an enzyme that promotes prostate cancer.
• Exercise. Regular aerobic exercise is associated with a reduced risk of prostate cancer.
• Take a multivitamin that includes vitamin D and antioxidants, especially selenium.
• Have regular screenings. Rectal exams can provide early detection of problems with the prostate gland.

We already know that the antioxidant lycopene that gives tomatoes their red color protects against prostate cancer. A new study of its effects published in the Nov. 5, 2003, issue of the Journal of the National Cancer Institute suggests that you get better protection by eating tomatoes (best when cooked in sauce) than by taking supplements. Lycopene is also found in watermelon and pink grapefruit.

To reduce your risk I also recommend drinking lots of water (dehydration stresses the prostate), adding soy foods to your diet, and eating less fat (high-fat diets stimulate production of sex hormones). Be sure to eat the right kinds of fat such as olive oil, avocados and nuts. Also, limit your intake of red meat and other sources of saturated fats and stay away from hydrogenated oils, processed foods and other sources of trans-fats. I would avoid coffee, decaffeinated coffee, alcohol, tobacco and red pepper – all are prostate irritants.

And incidentally, new research suggests that men who ejaculate more frequently between the ages of 20 and 50 are less likely to develop prostate cancer. The protective effect seems greatest for those in their 20s. Results from the study published in the August, 2003 issue of BJU International showed that men who ejaculated more than five times per week were one-third less likely to develop aggressive prostate cancer in their later years. The result contradicts an older belief that high frequency of sexual activity increases the incidence of prostate cancer.

Andrew Weil, M.D.