Diet and Prostate Cancer Prevention

Thousands of men are diagnosed with prostate cancer each year. It is the most commonly diagnosed type of cancer in American males other than skin cancer.

Some things, known as risk factors, increase your chances of getting the disease. For prostate cancer, the biggest risk factors are age and race. Men older than 50 and African-American men are at higher risk. Another risk factor, which is perhaps less influential but more under your control, is your diet. For some time now, research has shown that diet and nutrition likely play an important role in contributing to or preventing certain types of cancer, including prostate cancer. Health care professionals have made prevention recommendations based on the latest and most trustworthy findings.

Research on nutrition and cancer is a complex field, and progress and results come with difficulty. The good news is that diet is a risk factor that everyone can control. It's true that eating habits are hard to change. But what you eat, and how much of each type of food you eat, is your choice.

What aspects of diet seem to contribute to the risk of developing prostate cancer?

Most of the research seeking to identify the link between what men eat and their likelihood of getting prostate cancer has centered on saturated fat. Diets high in saturated fat are high in animal fat. Results of most studies indicate that men who eat a lot of saturated fat may have a greater chance of getting prostate cancer.

It isn't completely known why there seems to be a link between high fat intake and prostate cancer. One theory is that a diet high in saturated fat may increase testosterone levels. In turn, these higher hormone levels contribute to a greater risk of developing prostate cancer.

The most compelling connection of a high-fat diet to prostate cancer is found when experts look at who gets the disease across races and nationalities. African American men, who have the highest incidence rate, often have a diet high in animal fat. On the other end of the scale are Asian males, especially Japanese men living in Japan. They have the lowest rates for getting and dying of prostate cancer. The traditional diet in Japan is mostly vegetarian, so the amount of animal fat eaten is very low. Also, a vegetarian diet reduces, rather than increases, levels of testosterone.

Even more striking is what happens when men emigrate from Japan to the United States. Within two generations, their rates of getting prostate cancer increases to near that of American men. Typically, the traditional Japanese diet becomes more Americanized. That is, these men eat more animal fat. This move away from the vegetarian diet may explain the changes in this prostate cancer rate.

However, a few researchers have questioned whether high fat consumption itself is the primary culprit in the American diet. Some studies have indicated that men with a high-fat diet generally consume significant amounts of dairy products and low amounts of fruits and vegetables. Rather than high fat, the main connection to prostate cancer may be that this diet is high in dairy (or perhaps even calcium) and low in vegetables and fruits.

The precise role that diet plays in the development of prostate cancer is still under study.

What's the scientific evidence of the role of diet in preventing prostate cancer?

While studies of the amount of fat in a diet have been prostate cancer researchers' primary focus, other findings about the effect of what men eat continue to be made.

Lycopene is a substance naturally found in tomatoes and other red fruits, such as grapefruit and watermelon. It may help lower the risk for prostate cancer. This discovery was made in a well-publicized study in 1995. In it, the eating habits of 47,000 men were examined for six years. It was found that men who ate at least 10 servings a week of tomato-based food (all forms, cooked or uncooked) were up to 35 percent less likely to develop prostate cancer. Tomatoes and tomato products accounted for almost 90 percent of the lycopene in the diets of these men.

How might lycopene work? It's a natural antioxidant. Antioxidants are thought to prevent damage to a person's DNA. This may in turn protect against certain changes in DNA, which can cause prostate cells to grow abnormally.

Some studies done since that time have found that lycopene may lower the chance of getting prostate cancer, but others have not found such a link. More research needs to be done before lycopene or other antioxidants can be said to be preventive.

Some other studies have looked at the role that selenium, vitamins E and A, carotenoids, and other foods have in protecting against prostate cancer. Conclusions from these studies have not shown that these are protective.

How can I adapt my diet to lower my risk of getting prostate cancer?

Based on the majority of research, the American Cancer Society (ACS) has developed nutritional guidelines for a healthy approach to eating that may help lower your risk for many types of cancer, including prostate cancer.

The ACS recommends a diet that limits processed and red meats and is rich in fruits and vegetables, as well as whole grains instead of refined grains. Increasing the amount of fruits and vegetables you eat usually means that you will eat less high-fat and high-calorie foods. This type of diet, along with regular exercise, will also help you maintain a balanced, healthy weight for your height.