A Diet for Cancer?
The Dean Ornish solution.
What's the Evidence? continued...
Though nobody knows exactly why this is true, it may be that very early prostate cancers are kept in check by a plant-based diet -- or that something about the typical Western diet encourages microscopic lesions to become tumors. Studies in mice, Ornish says, have also shown that prostate tumors grew far more slowly -- and in some cases even regressed -- when the animals ate a diet low in fat.
Further support for this idea came in a study published in the July 2000 issue of the British Journal of Cancer. Researchers at the Imperial Cancer Fund in Oxford, England, found that men who eat a vegan diet have lower levels of a protein known as IGF-1. This protein's role in prostate cancer isn't fully understood, but the researchers say that, as with PSA, high levels of it are often found in men with the disease.
And though there is little research suggesting that exercise or stress management will affect prostate cancer, there is some data suggesting that these lifestyle changes can have a positive impact on other types of cancer. In a study published May 1, 1997, in the New England Journal of Medicine, researchers found that women who were more physically active were less likely to develop breast cancer than were less-active women.
For Ornish colleague Peter Carroll, MD, a urologist at the University of California, San Francisco, the evidence was enough to convince him that this approach was worthy of more thorough study. "This is a group of men who are at low risk because their cancers grow slowly, if at all," he says. "If lifestyle changes can make a difference -- particularly given the other benefits of such changes -- then we would have another treatment option for a substantial number of men."
In fact, as many as 10% to 15% of all men diagnosed with prostate cancer might be candidates for this approach, according to Carroll. This size of this group has convinced the U.S. Army to participate in a larger clinical trial with as many as 3,000 men, which should start this fall. "Given the data, I think that lifestyle changes hold a good deal of promise for the treatment of prostate cancer," said Colonel Judd Moul, MD, director of the Department of Defense's Center for Prostate Disease Research.