The findings of a US pilot study on men with low risk prostate cancer suggests that following an intensive healthy diet and lifestyle regime emphasizing low meat and high vegetable and fruit intake, regular exercise, yoga stretching, meditation and support group participation, can change the way that genes behave and alter the progress of cancer, for instance by switching on tumor killers and turning down tumor promoters.
The pilot study is the work of Dr Dean Ornish, founder and president of the Preventive Medicine Research Institute, and colleagues at the University of California, San Francisco (UCSF), and was published online on 16 June in the Proceedings of the National Academy of Sciences.
Ornish, who is also clinical professor at UCSF, and has built a reputation through his work on healthy diet and lifestyle, told a news conference that:
“We found that simple changes have a powerful impact on gene expression.”
Ornish said people sometimes think they can’t do anything because it’s all decided by their genes anyway, so what’s the point? But he called that attitude “genetic nihilism”, and said there may be an antidote, “Genes may be our predisposition, but they are not our fate,” said Ornish, reported in Scientific American.
Previous research had already shown that comprehensive changes in lifestyle and diet can change the progress of prostate cancer, but the underlying molecular mechanisms, especially in the micro-environment of the prostate, remained somewhat of a mystery.
For the pilot study, Ornish and colleagues enrolled 31 men with low risk prostate cancer who had opted for “watchful waiting”, that is they had declined immediate surgery, hormonal therapy, or radiation. Instead, they chose to follow an intensive nutrition and lifestyle regime while being monitored for tumor progression.
In the intensive diet, physical exercise and stress-reduction intervention, the men walked or worked out for 30 minutes six times a week, did yoga stretches, breathing and meditation sessions for an hour every day, and every week they also took part in one hour group support sessions.
They also followed an almost vegan diet, with a much reduced intake of meat and fats, and a much higher intake of fruits, vegetables, and whole grains, supplemented with soy, fish oil, selenium and vitamins C and E.
The results showed that:
- In line with previous studies, the men experienced statistically significant improvements in weight, abdominal obesity, blood pressure, and blood fat levels (lipid profile).
- Using technology involving “significance analysis of microarrays”, changes in gene expression were observed by sampling 30 of the participants, whose RNA samples taken before the intervention compared with RNA samples taken 3 months into it, showed 48 transcripts had up-regulated and 453 had down-regulated.
- By analyzing the genetic pathways of these transcripts, the researchers were able to identify they played a significant role in tumor formation and development, including protein metabolism, protein traffic between cells, and protein phosphorylation.
An RNA transcript is a group of instructions encoded by DNA which tells RNA how to go about synthesizing proteins that regulate cell behaviour. It is the first stage of gene expression. Genes don’t control cells directly, they have to encode their messages, like telegrams, and send them via RNA messengers that control the making of proteins that tell cells what to do. Protein phosphorylation, where a phosphate group is added to a protein, is thought to be how the protein is “switched on”.
In a nutshell, Ornish and colleagues believe they found that the up-regulated transcripts were mostly for tumor suppression, and the down-regulated ones were for tumor promotion, the so-called “oncogenes”.
The researchers concluded that:
“Intensive nutrition and lifestyle changes may modulate gene expression in the prostate,” adding that:
“Understanding the prostate molecular response to comprehensive lifestyle changes may strengthen efforts to develop effective prevention and treatment.”
The researchers said larger clinical trials are now needed to confirm the results of this pilot study.
Co-author and geneticist at UCSF, Dr Christopher Haqq, said at the news conference reported by Scientific American that:
“It is absolutely intriguing this lifestyle change can have as much effect as the most powerful drugs available to us now.”
“We medical oncologists are always looking for drugs that can do this. It is delightful to find that diet and lifestyle can have profound effects and be complementary to drug therapies – with fewer side effects,” he added.
Ornish said the biggest surprise was how little time it took for the changes to show. People are usually unmotivated to change because they think it will be a long time before benefits begin to show, but, as Ornish explained:
“It is not really so much about risk-factor reduction or preventing something bad from happening. These changes can occur so quickly you don’t have to wait years to see the benefits.”
“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.
Proceedings of the National Academy of Sciences Vol 105, No 24, pp 8369-8374 .
Published online on 16 June 2008.
Source: PNAS, Scientific American.
Written by: Catharine Paddock, PhD