US scientists claim that 11 days of daily exercise and a special diet, low in fat and high in fruits, vegetables, and whole grains, induce prostate cancer cells to die.
The research, released by the Pritikin Longevity Center and published in the current issue of Cancer Causes and Control, looks at the merits of the Pritikin Program, which includes regular exercise and a very low-fat, high-fibre diet.
"You can make changes in a short period of time that have a dramatic impact on your health - in this case, on the growth and death of prostate cancer cells," said R. James Barnard, professor of physiological science at UCLA and lead investigator on the study.
Barnard and UCLA colleagues studied two groups of men: 14 obese men, ages 42 to 73, who attended an 11-day diet and exercise programme at the Pritikin Longevity Center, and eight normal-weight men, ages 38 to 74, who have followed the Pritikin Program for nearly 15 years.
The researchers collected blood serum samples from the 14 obese men before they began their 11-day Pritikin Program. At UCLA, they mixed the serum samples in dishes with prostate cancer cells. At the end of the 11-day programme, they collected a second set of blood samples from the 14 men and mixed them with a second set of prostate cancer cells.
With the first set of blood samples, those taken from the men before they began the Pritikin Program, the LNCaP prostate cancer cells grew vigorously in the cell cultures. Fewer than 3 per cent showed apoptosis (programmed cell death).
At the conclusion of the 11-day programme, the prostate cancer cells grew much more slowly, report the researchers. They said that almost 40 per cent of the cells were on their way to death. The prostate cancer cells grew even more slowly in the serum from the eight men who had been following the Pritikin Program for 15 years.
The team added that over 50 per cent of the cells were in the throes of apoptosis, or programmed death. "That was the finding that made our jaws drop," Barnard said. "We don't know yet whether these dramatic changes that occurred to prostate cancer cells cultured in a laboratory will also occur in patients, but we certainly suspect they do, and we're launching research to find out."
Prostate cancer is the second leading cause of cancer death in men, exceeded only by lung cancer.