Diet, Stress Reduction May Slow Prostate Tumors
Tuesday December 4, 2001
NEW YORK (Reuters Health) - A low-fat, high-fiber diet coupled with stress reduction may slow the growth of prostate tumors, results of a small study suggest.
Researchers found that a plant-based diet combined with a stress reduction program lowered the rate at which prostate specific antigen (PSA) increased in 8 of 10 men over 4 months. Levels of PSA, a protein produced by the prostate, are used to screen for cancer.
According to the report in the December issue of The Journal of Urology, more than one third of men treated for prostate cancer will have a recurrence marked by elevated PSA levels within 10 years. And in many of these men, the cancer will spread to other parts of the body.
Several studies suggest that the Western diet, marked by a high intake of saturated fat from meat and dairy and a low intake of fiber from fruits and vegetables, is associated with an increased risk of prostate cancer and more malignant tumors. There is also preliminary evidence that after it develops, prostate cancer may be "sensitive" to diet. A possible explanation is that low-fat, high-fiber diets can reduce levels of male hormones circulating in the blood, according to the researchers.
These new findings suggest a way for prostate cancer patients to modify risk factors for tumor progression while minimizing risk factors for heart disease and diabetes, and improving their quality of life, Dr. Gordon A.
Saxe, from the University of California, San Diego, and colleagues report. [An abstract if below.]
"Our small study provides evidence that a plant-based diet delivered in the context of (a stress-reduction program) decreases the rate of PSA increase and may slow the rate of tumor progression in cases of...recurrent prostate cancer,"they conclude.
The 10 study volunteers, who had all undergone radical prostatectomy, or removal of the prostate, were in the early stages of recurrent prostate cancer. They received individual nutrition counseling and followed a diet rich in whole grains, legumes, fresh vegetables, soy-based food and fruit.
Caffeine, animal-based foods and processed and refined foods were strictly limited.
Patients also participated in 12 weekly group stress-reduction sessions lasting 3 to 4 hours. The patients were accompanied by someone close to them, in most cases a spouse.
After 4 months, the rate of tumor progression was found to have slowed in 8 of the 10. In three men, PSA levels had actually decreased, according to the report. All men lost weight.
Saxe and colleagues suggest that future research try to confirm the findings and investigate the mechanism by which diet and stress reduction might prolong the lives of men with recurrent prostate cancer.
SOURCE: The Journal of Urology 2001;166:2202-2207.
CAN DIET IN CONJUNCTION WITH STRESS REDUCTION AFFECT THE RATE OF INCREASE IN PROSTATE SPECIFIC ANTIGEN AFTER BIOCHEMICAL RECURRENCE OF PROSTATE CANCER?
GORDON A. SAXE; JAMES R. HEBERT; JAMES F. CARMODY; JON KABAT-ZINN; PENNY H. ROSENZWEIG; DAVID JARZOBSKI; GEORGE W. REED; ROBERT D. BLUTE
Purpose: Epidemiological and laboratory evidence indicates that a Western diet is associated with an increased incidence of prostate cancer.
Specific components of the diet, such as high saturated fat, low fiber and high meat content, may have greatest clinical significance in the later stages of tumor promotion and progression. However, departure from the conventional diet is difficult to initiate and maintain. Therefore, we combined the well-known Mindfulness-Based Stress Reduction (MBSR) program with a low saturated fat, high-fiber, plant-based diet to determine the effect on the rate of change in prostate specific antigen (PSA) in patients with biochemical recurrence after prostatectomy.
Materials and Methods: We enrolled 10 men and their partners in a 4-month group-based diet and MBSR intervention. A pre-study post-study design in which each subject served as his own control was used to compare the rate of increase in and doubling time of PSA before and after intervention.
Results: The rate of PSA increase decreased in 8 of 10 men, while 3 had a decrease in absolute PSA. Results of the signed rank test indicated a significant decrease in the rate of increase in the intervention period (p = 0.01). Estimated median doubling time increased from 6.5 months (95% confidence interval 3.7 to 10.1) before to 17.7 months (95% confidence interval 7.8 to infinity) after the intervention.
Conclusions: Our small study provides evidence that a plant-based diet delivered in the context of MBSR decreases the rate of PSA increase and may slow the rate of tumor progression in cases of biochemically recurrent prostate cancer. Larger-scale randomized studies are warranted to explore further the preventive and therapeutic potential of diet and lifestyle modification in men with prostate cancer.