Prostate cancer patients who followed an extremely low fat diet and an exercise and stress management regimen turned on cancer preventing genes and turned off genes linked to triggering the disease.
A new study from the Preventive Medicine Research Institute in Sausalito, Calif., found that men who had been diagnosed with prostate cancer and had refused conventional treatment altered more than 500 genes when following a strict diet and exercise plan.
Lead study author Dr. Dean Ornish said the study offers hope to people who fear they won't be able to escape their genetic predisposition to illness.
"So it is a very hopeful finding," Ornish said.
"So often people say, I have bad genes what can I do? Turns out you can do a lot more than you thought."
Doctors conducted needle biopsies of the prostates of 30 men before and then again three months after they started the new lifestyle program.
The regimen entailed four components:
- A very low-fat, meat-free diet rich in fruits, vegetables, legumes, soy products and whole grains, with fish oil, selenium, vitamin C and vitamin E supplements.
- A moderate exercise program that required about 30 minutes of walking per day.
- Stress management techniques such as yoga-based stretching, breathing exercises and meditation.
- A weekly one-hour support group.
Jack McClure was diagnosed with prostate cancer six years ago and decided to forgo surgery, radiation and chemotherapy to enroll in Ornish's study.
Now, there is no sign of the disease in his body.
"My latest biopsy, they couldn't find any cancer cells at all," McClure said.
"I'm not ready to say I'm cured of cancer. They just can't find it anymore."
The researchers did say that despite the findings, lifestyle changes are not a substitute for standard cancer therapies such as chemotherapy and radiation.
Dr. Neil Fleshner, head of urology at the University Health Network in Toronto, approached the study's findings with caution. He said that because the testing was conducted on normal prostate tissue and not on the cancer cells themselves, there is no way to know what effect the lifestyle changes would have on the cancer itself, despite the experience of McClure.
Fleshner also said that it is unclear whether the gene changes were most influenced by the diet, the exercise regimen or the stress-management plan.
However, lifestyle changes play an important role in the prevention and treatment of cancer.
"The major message from this and other studies on diet, lifestyle and cancer is that it does appear to be a lifestyle-related condition and that alterations in lifestyle not only may be able to prevent us from getting cancer, but may be useful adjuncts to standard cancer therapy," Fleshner said.
The findings were published in the journal Proceedings of the National Academy of Sciences.
With a report from CTV medical specialist Avis Favaro and senior producer Elizabeth St. Philip.
Abstract:
Changes in prostate gene expression in men undergoing an intensive nutrition and lifestyle intervention
Dean Ornish, Mark Jesus M. Magbanua, Gerdi Weidner, Vivian Weinberg, Colleen Kemp, Christopher Green, Michael D. Mattie, Ruth Marlin, Jeff Simko, Katsuto Shinohara, Christopher M. Haqq and Peter R. Carroll
Epidemiological and prospective studies indicate that comprehensive lifestyle changes may modify the progression of prostate cancer.
However, the molecular mechanisms by which improvements in diet and lifestyle might affect the prostate microenvironment are poorly understood. We conducted a pilot study to examine changes in prostate gene expression in a unique population of men with low-risk prostate cancer who declined immediate surgery, hormonal therapy, or radiation and participated in an intensive nutrition and lifestyle intervention while undergoing careful surveillance for tumour progression.
Consistent with previous studies, significant improvements in weight, abdominal obesity, blood pressure, and lipid profile were observed (all P<0.05), and surveillance of low-risk patients was safe.
Gene expression profiles were obtained from30 participants, pairing RNA samples from control prostate needle biopsy taken before intervention to RNA from the same patient's 3-month post intervention biopsy. Quantitative real-time PCR was used to validate array observations for selected transcripts. Two-class paired analysis of global gene expression using significance analysis of microarrays detected 48 up-regulated and 453 down-regulated transcripts after the intervention. Pathway analysis identified significant modulation of biological processes that have critical roles in tumorigenesis, including protein metabolism and modification, intracellular protein traffic, and protein phosphorylation (all P < 0.05). Intensive nutrition and lifestyle changes may modulate gene expression in the prostate.
Understanding the prostate molecular response to comprehensive lifestyle changes may strengthen efforts to develop effective prevention and treatment. Larger clinical trials are warranted to confirm the results of this pilot study.
