When it comes to preventing prostate cancer, the science is clear: Men who steer clear of milk have significantly lower rates of the deadly disease. According to the World Cancer Research Fund and the American Institute for Cancer Research, 11 separate human population studies have tied dairy consumption to prostate cancer.

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The American Cancer Society points out that "about one-third of the 500,000 cancer deaths that occur in the United States each year is due to dietary factors…Although the committee recognizes that no diet can guarantee full protection against any disease, we believe that our recommendations offer the best nutrition information currently available to help Americans reduce their risk of cancer." The Society's top two recommendations are: "1. Choose most of the foods you eat from plant sources"; and "2. Limit your intake of high-fat foods, particularly from animal sources."

Results of the landmark Physicians' Health Study of 20,885 doctors showed that men who consumed at least 2-1/2 servings of dairy foods daily were about 30 percent more likely to develop prostate cancer than men who averaged less than half a serving per day.

The Health Professionals Follow-Up Study found that men who consumed high amounts of dairy products had a 70 percent increased risk of prostate cancer.

A study of 41 countries published in Alternative Medicine Review found that as milk consumption rose, so did prostate cancer mortality rates.

British researchers have found that men who eat a diet without dairy products and meat have lower levels of a certain protein associated with prostate cancer. The study, published in the British Journal of Cancer , found that levels of IGF-1 – an insulin-like growth factor believed to play a key role in causing prostate cancer – were 9 percent lower in vegans than in nonvegans.

Studies published in the Journal of the American Dietetic Association and the British Medical Journal found that consuming three additional servings of nonfat or 1 percent milk for 12 weeks was associated with a 10 percent increase in IGF-1 levels.

Ready to reach for the soy milk? Click here for delicious dairy-free recipes.

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For more information, check out this article about milk and prostate cancer or visit the Physicians Committee for Responsible Medicine analysis of diet and prostate cancer.

This essay , from the Alternative Medical Review , distills all of the epidemiological studies and argues that the link between dairy products and prostate cancer is absolutely conclusive.

Cancer and the Vegetarian Diet, by William Harris, M.D.

For an article about Bovine Growth Hormone and prostate cancer, click here .