Why Prostate Supplements Don't Work
Patients often ask me what vitamins they can take to protect them from prostate cancer and to ensure optimum prostate health. My answer is brief and direct: There are no supplements that will prevent or treat prostate cancer. Vitamins and supplements are largely unregulated and they can cause more harm than good.
The latest study
Men often walk down drugstore and health-food store aisles and see bottles of pills labeled “men’s health” or “prostate health.” We call these pills “men’s health supplements.” My colleagues and I at Fox Chase Cancer Center recently completed a first-of-its-kind study of over-the-counter men’s health supplements to test how well they work against prostate cancer.
Men’s health supplements are often mislabeled as having potential anti-cancer or healing effects. Men with prostate cancer commonly use these pills because of the high incidence of prostate cancer (about 1 in 6 men will be diagnosed with the disease), the stress associated with the diagnosis, the desire to benefit from all potential treatments, and the limited regulation on marketing and sale of the supplements. Many men believe the supplements will help their cancer or (at worst) do nothing—so what’s the harm?
For our team, the big question, of course, was “Do these men’s health supplements offer any benefit to men with prostate cancer?” The answer is “no.” We had suspected that the supplements were junk, and our recent study confirmed it.
In our study, which we presented at the Annual Meeting of the American Society for Radiation Oncology (ASTRO) in San Antonio in October 2015, we reviewed a comprehensive cancer center database of 2,301 men who underwent intensity-modulated radiation therapy—or IMRT, the most sophisticated form of radiation therapy currently available—for localized prostate cancer between 2001 and 2012.
At the time of IMRT or during follow-up, 10 percent of these individuals took men’s health supplements, which were defined as any medication marketed with any of the following terms: men’s health, men’s formula, prostate health, or any combination of these words.
Excluded from our study were general multivitamins, minerals, or prescription medications, unless they had these terms. We had a broad definition of men’s health supplements; this was because we wanted to incorporate all of the potential choices that men would have at a grocery store or drugstore. We searched online for each men’s health supplement and found that none was ever tested in any studies, despite the claims on their labels. Many were marketed as being “clinically proven,” even though the anticipated effect was never provided.
The most common ingredient, present in 91 percent of the supplements, was saw palmetto, an extract of a fruit and a commonly used herbal medicine. Men often use this over-the-counter supplement to treat symptoms of an enlarged prostate (also called benign prostatic hyperplasia (BPH) or benign prostatic enlargement (BPE), despite the lack of any data to support its use. In our study, men’s health supplements typically had saw palmetto and about two other ingredients listed on the label. Some listed more than 70 ingredients. We did not perform any chemical analyses of the pills, so we were never sure what the pills actually contained.
At the follow-up five years after IMRT, we found that when it came to prostate cancer, men taking men’s health supplements did not have a lower risk of cancer spreading to other parts of the body, death from cancer, or adverse effects associated with radiation therapy, compared with men who did not take these supplements.
Our study is not the first to suggest that supplements are not helpful for prostate cancer patients. The SELECT (Selenium and Vitamin E Cancer Prevention Trial), the largest-ever prostate cancer prevention trial, confirmed the potential danger of taking certain medications.
In the 1980s and 1990s, studies had suggested that selenium and vitamin E, alone or in combination, might reduce the risk of developing prostate cancer. (Selenium is obtained mostly from plant sources, tuna, and some meat; vitamin E is found in whole grains and nuts.) This intrigued researchers, so the National Cancer Institute sponsored SELECT in 2001 to evaluate both nutrients. The results of the study were published in 2011, and the data showed that men who took vitamin E alone had a 17 percent relative increase in numbers of prostate cancers compared to men on placebo.
I urge all men to take caution when they see bottles of pills labeled “men’s health” or “prostate health.” Although we did not see a change in adverse effects with our patient group, there have been thousands of cases in the United States where supplements have harmed patients. An estimated 23,000 emergency-department visits in the U.S. every year are attributed to adverse events related to dietary supplements. Additionally, men’s supplements are expensive, costing anywhere from $10 a month to $150 for a 30-day supply.
Instead of prostate supplements, a more effective source of protection against prostate cancer is a healthy lifestyle, which includes a nutritious diet and regular exercise. A good diet should provide you with all of the “supplements” you need. It’s hard to say what exactly constitutes the perfect diet, but I follow these general guidelines when it comes to healthful eating:
• Food should not have ingredients; it should be the ingredient. In other words, at the supermarket, instead of buying a product that says “contains spinach” because you want its vitamins or minerals, just buy real spinach instead, which contains many important nutrients. Use that green, leafy vegetable to make your meal. Avoid all food products that contain more than five ingredients, artificial ingredients, or ingredients you can’t pronounce.
• Shop the perimeter. The best foods are typically found on the perimeter of the market, and they generally have an expiration date (for example, fruits, vegetables, fish, meat, and eggs). This is in stark contrast to food located in the aisles (for example, potato chips, cookies, sugary cereals, microwavable meals, and an endless variety of junk foods).
Nicholas G. Zaorsky, M.D., is a chief resident physician in radiation oncology at Fox Chase Cancer Center in Philadelphia.