My husband has prostate cancer. Are your nutrition guidelines appropriate for him, too?

Yes, many men with prostate cancer have followed the guidelines in my book, along with some type of conventional cancer therapy, with success. The following article will provide much information specific to prostate cancer and nutrition that you will find helpful.

FAQ posted 4/01, updated 5/02

"Fighting prostate cancer: eat your way to victory"
Sue Rose, MS, RD
Private Practice and Consultant, Park Ridge, IL
Staff dietitian, Cancer Wellness Center, Northbrook, IL

If you could reduce your risk of prostate cancer by adjusting your diet, would you do it? If you knew that 179,000 new cases of prostate cancer would be diagnosed this year, and that 37,000 men would die, would you reconsider your answer?

There is mounting evidence that diet is strongly linked to prostate cancer-the second most common cause of cancer-related death in American men. Though the statistics sound gloomy, the good news is that the diet you eat today may actually delay or prevent the development of prostate cancer down the road. In Asia, for example, the percentage of men who develop prostate cancer is far less than that of the United States, and the prostate cancer that develops in Asian men is more curable. Researchers have long speculated that certain aspects of the Asian diet may be protective against prostate cancer. And in certain Mediterranean countries such as Greece and Italy, the rate of prostate cancer is also low; some researchers speculate that diet is a factor there, as well.

Isoflavones

Compounds called isoflavones, found mainly in soybeans, are present in the Asian diet, but are virtually absent in the typical American diet. Asians eat the whole soybean or minimally processed by-products of the soybean, such as tofu and soymilk. It is estimated that Japanese men consume up to 200 mg of isoflavones per day while other Asian men consume 25-45 mg. American men, however, typically consume less than 5 mg of isoflavones per day.

Isoflavones may exert anti-tumor properties in a variety of ways. They might play a role in prohibiting the formation of new blood vessels that are necessary to feed a growing cancer. Since prostate cancer is a hormone-dependent cancer, the isoflavones may lower the hormones that trigger prostate cancer, theoretically lessening the likelihood of the cancer growing.

Good sources of isoflavones include:

Tofu - available in most refrigerated produce or dairy sections of your local supermarket. You can make a healthy shake by blending together 1/2 cup of tofu with a banana, orange juice, and other fruit.

Flavored soymilk - available in chocolate, vanilla, strawberry or coffee, yields about 40 mg of isoflavones in a one-cup serving and is made by several different companies.

Soynuts - available in all health food stores, these yield 60 mg of isoflavones per 1/4 cup.

Green tea

Green tea contains cancer-preventing compounds called flavonoids, which act as antioxidants. Several studies performed in animals suggest that one particular flavonoid, epigallocatechin gallate (EGCG), may have the ability to stop tumors from spreading. Japanese researchers have noted that cancer onset in patients consuming 10 cups of green tea per day seems to be three to eight years later when compared with people who consume three or less cups of green tea. The typical Asian consumes an average of five cups of green tea per day.

According to Dr. Douglas Balentine of the Lipton Tea company, if green tea is steeped for only one minute, the average flavonoid content is 208 mg. If it is steeped for four minutes, the flavonoid content increases to 300 mg.

Red fruits and vegetables

Lycopene is part of a group of compounds called carotenoids that are known for their antioxidant properties, which may include the ability to inhibit cancer. Where can you find lycopene- Watermelon and pink grapefruit contain lycopene, but tomato-based foods contain the most. When tomato-based foods are heated and mixed with a small amount of oil, the lycopene absorption is maximized. That makes cooked tomato products excellent sources of lycopene.

In one oft-reported study, Dr. Edward Giovannucci of the Harvard Medical School examined the diets of more than 47,000 males over a six-year period. He noted a correlation between prostate cancer and a marginal intake of tomato-based foods, which contain large amounts of lycopene. Men who ate ten or more servings per week of tomato-based foods had a 45 percent lower likelihood of developing prostate cancer.

"The jury is still out on lycopene," says Colleen Doyle, M.S., R.D., nutrition and physical activity director for the American Cancer Society (ACS). "Earlier studies have not consistently shown that men who consume more lycopene are at a reduced risk of developing prostate cancer." However, Doyle points out that tomatoes are still an important part of a healthy diet. "Everyone should eat at least five servings of a wide variety of fruits and vegetables every day and tomatoes are a great way to get in your five daily vegetable servings," she says.

Cruciferous vegetables

A recent study from the Fred Hutchinson Center in Seattle confirms that all vegetables may help reduce the risk of prostate cancer. According to Alan Kristal, Dr.P.H., "eating a lot of vegetables can cut your risk of prostate cancer by about 45 percent. And if those vegetables are from the cruciferous family, like cabbage and broccoli, you may reduce your risk even further."

This study-which examined the risks for prostate cancer in younger men (ages 40 to 64)-looked at the associations between overall fruit and vegetable consumption as well as specific fruits and vegetables and prostate cancer risk.

In the study, men who ate three or more servings per day of vegetables had a 48 percent lower risk of prostate cancer, compared with men who ate less than one serving per day. This association was independent of other dietary factors (such as fat intake) and a history of prostate cancer in a father or a brother. The strongest correlation was noted with the cruciferous vegetables-broccoli, cauliflower, cabbage, and Brussels sprouts.

Vitamin E

It has been speculated that the typical high fat intake in the western diet may accelerate prostate cancer. A recent study at Sloan Kettering Institute for Cancer Research noted that the antioxidant effects of vitamin E seem to halt prostate tumor growth in mice, which was initially triggered by a high-fat diet. Research continues to suggest that 200-400 IUs (international units) of supplemental vitamin E may be helpful for all Americans, so this is one supplement that may be beneficial for both prostate health and overall health.

Fiber

Prostate cancer is a hormone-dependent cancer. Any aspect of the diet that binds hormones could have a positive effect on prostate health. Dietary fiber, for instance, may remove hormones from the system. It has been found that men who eat more fruits, vegetables, and whole grains-all excellent sources of fiber-have lower circulating levels of male hormones. The National Cancer Institute recommends consuming at least 25 grams of fiber per day. A 1/2-cup serving of fruit or vegetables contains about 2 grams of fiber; a slice of whole grain bread 5 grams; and a 1/2-cup serving of high fiber cereal a whopping 14 grams.

The bottom line?

No one food or supplement can protect you from prostate cancer. A diet that is lower in fat, contains at least five servings per day of fruits and vegetables, and the addition of soy-based products will go a long way in protecting your prostate.

Addendum by Diana Dyer, MS, RD
Some (but not all) recent studies suggest that higher intakes of milk may increase risk for prostate cancer. The American Institute for Cancer Research (AICR) has reviewed all the available scientific literature to date on this issue and has published a summary on its website. Not enough of the science is fully understood about this possible connection to issue dietary guidelines. However, it is prudent at this point for men to keep their calcium intake (from both food and supplement sources) to the DRI of 1000 mg/day and to make sure they are getting at least the DRI for Vitamin D of 400 IU/day (from fortified foods or supplement sources).

Resources

CaP Cure: Association for the Cure of Cancer of the Prostate
U.S. Soyfoods Directory
Lycopene.org - a web site dedicated to information on lycopene
American Institute for Cancer Research

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These questions and answers are intended to be of a general informative nature. Please consult with the Registered Dietitian in your cancer center or your health care provider for nutritional advice that can be individualized to your specific medical condition.