Low-fat, vegetarian diet may stall prostate cancer

NEW YORK (Reuters Health) - Low-fat, plant-based diets may help prevent or slow the progression of prostate cancer, according to a new research review.

A number of studies, though not all, have suggested that eating plenty of fruits and vegetables may help ward off prostate cancer, while "Western"-style diets heavy in animal fat and dairy products may increase a man's risk of developing the disease.

In the current study, researchers reviewed 25 previously published studies that examined the effects of plant-based diets on prostate cancer development or progression.

Overall, the evidence suggests that diets high in fiber, fruits and vegetables, and low in meat and dairy, can help battle the disease, they report in the journal Nutrition Reviews.

For example, several studies of men with prostate cancer have linked high saturated fat intake to faster disease progression and a higher risk of death. Saturated fat is found mainly in animal products.

In contrast, some small trials have found that a high-fiber, low-fat vegetarian diet may slow the growth and spread of early-stage prostate tumors. Some other studies have suggested that components of plant-based foods -- like certain antioxidants or soy isoflavones -- might be beneficial.

"For men diagnosed with prostate cancer, the key to improving the odds of survival is avoiding high-fat fare and instead choosing fruits, vegetables, beans and other cancer-fighting vegetarian foods," lead study author Dr. Susan Berkow said in a statement.

Berkow is with George Mason University in Alexandria, Virginia, and serves as a consultant to Physicians Committee for Responsible Medicine, a group that advocates vegetarian and vegan diets.

Berkow and her colleagues speculate that the fiber and other nutrients found in plant-based diets may affect prostate cancer by altering levels of certain hormones that can feed tumor development, including testosterone and insulin.

The balance of fats in a man's diet may also be key, the researchers point out. Some studies have found that omega-3 fatty acids may help stall prostate cancer progression. Omega-3 fats are found largely in oily fish, but also in some vegetable sources, like flaxseeds and canola oil.

SOURCE: Nutrition Reviews, September 2007.