Dairy Products, Calcium, and Vitamin D. Studies have reported an association between consuming large amounts of dairy products and a modestly increased risk for prostate cancer. (Moderate intake has not been associated with a higher risk.) That is some evidence that calcium (contained in dairy products) may increase the risk for prostate cancer by reducing levels of the most active form of vitamin D (1,25 dihydroxyvitamin D), which may protect against prostate cancer. In fact, some research is focusing on prostate treatments using vitamin D analogs. There is still no clear proof, however, that high calcium and low vitamin D levels pose a significant risk for prostate cancer.
 | Click the icon to see an image of the benefits of vitamin D. |
 | Click the icon to see an image of the sources of vitamin D. |
Vitamins and Mineral Supplements
Vitamin D. Vitamin D may help protect against prostate cancer. Some studies suggest that higher blood levels of vitamin D are associated with a lower risk of prostate cancer. Men should make sure they are getting enough vitamin D through sunlight exposure, food, or vitamin supplements.
Vitamin E. Vitamin E is being investigated for possible protection against prostate cancer. To date, four trials have found that vitamin E may provide some reduction in risk for past and current smokers and for men with vitamin E deficiencies. Of concern was an association in one study of a higher risk for aggressive prostate cancer in nonsmoking men who took high doses of vitamin E (100 IU or greater).
 | Click the icon to see an image of the benefits of vitamin E. |
 | Click the icon to see an image of the sources of vitamin E. |
Selenium. Selenium is a trace mineral found in Brazil nuts, most red meats, poultry, shellfish, and dark mushrooms. In laboratory studies, selenium has acted directly on prostate cancer cells, stimulating cell death and inhibiting growth. In one 2003 study, selenium levels were measured in toenail clippings. Those with the highest levels had the lowest risk for prostate cancer. The findings were particularly pronounced in ex-smokers. Other studies on significant protection from selenium supplements against prostate cancer, however, have been weak. It is possible that supplements may benefit only those who have selenium deficiencies.
The National Cancer Institute is conducting a large-scale clinical trial of more than 35,000 men to investigate whether selenium, vitamin E, or a combination of these two dietary supplements can help to prevent prostate cancer. The Selenium and Vitamin E Cancer Prevention Trial (SELECT) is the largest prostate cancer prevention trial ever initiated.
Zinc. Zinc is of interest because it accumulates to the highest levels in a man's body in either a normal prostate or one enlarged from benign prostate hyperplasia. Some laboratory studies suggest that zinc might inhibit activation of prostate cancer cells. A 2003 study, however, reported that men taking zinc supplements in high doses (100 mg) had a higher risk for advanced prostate cancer. Of note, such men also took higher levels of calcium, iron, and other supplements that might have biased these results. More research is needed to determine the role of zinc on prostate health.
Alcohol
Alcohol consumption does not appear to be associated with increased prostate cancer risk. A recent study, however, suggested a linear trend between red wine consumption and reduced risk of prostate cancer. In a study of over 1400 newly diagnosed middle-aged prostate cancer patients and matched controls, researchers found that each additional glass of red wine consumed per week reduced the relative risk of prostate cancer by 6%. Researchers theorize that the flavonoids contained in red wine may inhibit tumor cell growth. More research is needed to confirm these results.
Exercise
Regular physical activity may help reduce the risk of prostate cancer and slow the progression of the disease. The beneficial effects of exercise may be particularly important for older men. A 2006 study found that men ages 65 and older who exercised vigorously for at least 3 hours weekly had a 70% lower risk of being diagnosed with advanced prostate cancer.
Finasteride (Proscar)
Finasteride (Proscar) is a drug used to shrink the prostate in men with benign prostatic hyperplasia (BPH). It blocks an enzyme that converts testosterone to dehydroepiandrosterone (DHEA), the form of the male hormone that stimulates the prostate. Researchers are investigating whether finasteride may help prevent prostate cancer. In the 2003 Prostate Cancer Prevention Trial (PCPT), more than 18,000 men were randomly assigned to receive either finasteride or placebo. The men took the pills daily for 7 years. Results, published in 2003 in the New England Journal of Medicine, indicated that men who took finasteride were 25% less likely to develop prostate cancer than men who took placebo. However, although the finasteride group had less prostate cancers overall, those which did develop were higher-grade and more aggressive. Men who took finasteride had more sexual problems, including episodes of erectile dysfunction, but were less likely to have urinary problems such as incontinence. It is still unclear if finasteride is an appropriate preventive approach.
Sexual Activity
Frequent ejaculations from masturbation or sexual activity have been associated with a lower risk for prostate cancer. Some experts speculate that certain carcinogens may be concentrated in prostate fluid, so that frequent ejaculation helps eliminate them. Of note, risky sexual activity, such as with multiple partners, increases the risk for sexually transmitted disease, which in turn may increase the risk for prostate cancer.
Nonsteroidal Anti-inflammatory Drugs (NSAIDs)
There is some evidence that nonsteroidal anti-inflammatory drugs (NSAIDs) offer some protection against prostate cancer. NSAIDs suppress chemical in the body called COX-2, a protein that may cause prostate cancer cells to spread. Standard NSAIDs include aspirin, ibuprofen (Advil), and naproxen (Aleve, Naprosyn, Naprelan, Anaprox). Many other NSAIDs, such as sulindac (Clinoril), are available only by prescription and are being studied for protection. A 2002 study reported a 50% reduction in the risk for prostate cancer in men over 60 who took a daily NSAID, although conclusive evidence is still needed.
Previous Section
