'This adds new evidence that changing diet and lifestyle may help to prevent prostate cancer.'

The research is the first randomized, controlled trial showing that lifestyle changes may affect the progression of any type of cancer, say the authors.

The directors of the study were Dean Ornish, MD, clinical professor, and Peter Carroll, MD, chair of the Department of Urology, both of the University of California, San Francisco, and the late William Fair, MD, chief of urologic surgery and chair of urologic oncology, Memorial Sloan-Kettering Cancer Center.

Body and MInd Approach

The researchers studied 93 men who had elected not to undergo conventional treatment for their prostate cancer for reasons unrelated to this study. The participants were assigned randomly to two groups: those who were asked to make comprehensive changes in diet and lifestyle, and those who were not asked to do so.

Participants in the lifestyle-change group were placed on a vegan diet consisting primarily of fruits, vegetables, whole grains and legumes supplemented with soy, vitamins and minerals. They participated in moderate aerobic exercise, yoga or meditation, and a weekly support group session.

A registered dietitian was available for consultation, and a nurse case manager contacted the participants once a week for the first three months and weekly thereafter.

After one year, levels of PSA -- a protein marker for prostate cancer -- decreased in men in the group who made lifestyle changes but increased in the comparison group, the researchers found.

They noted a direct correlation between the degree of lifestyle change and the changes in PSA.

Also, serum from the participants inhibited prostate tumor growth in vitro by 70 percent in the lifestyle-change group but only 9 percent in the comparison group. Once again, the researchers found a direct correlation between the degree of lifestyle change and the inhibition of prostate tumor growth.

Better Lives

Patients in the lifestyle-change group reported marked improvements in quality of life, the authors note.

None of the lifestyle-change participants had such conventional prostate cancer treatments as surgery, radiation or chemotherapy during the study. However, six members of the comparison group underwent conventional treatments because their disease had progressed.

"This study provides important new information for men with prostate cancer and all men who hope to prevent it," says Carroll. "This is the first in a series of trials attempting to better identify the exact role of diet and lifestyle in the prevention and treatment of prostate cancer," he points out.

"Changes in diet and lifestyle that we found in earlier research could reverse the progression of coronary heart disease may also affect the progression of prostate cancer as well," says Ornish, who is also founder and president of the non-profit Preventive Medicine Research Institute.

"These findings suggest that men with prostate cancer who undergo conventional treatments may also benefit from making comprehensive lifestyle changes," he observes. "This adds new evidence that changing diet and lifestyle may help to prevent prostate cancer."