Low Fat Diet and Telomere Length in Prostate Cancer Patients

Ornish D, Lin J, Chan JM, et al. Effect of comprehensive lifestyle changes on telomerase activity and telomere length in men with biopsy-proven low-risk prostate cancer: 5-year follow-up of a descriptive pilot study. Lancet Oncol. 2013 Oct;14(11):1112-1120.

 

Non-randomized trail. 10 patients from a previous study were compared to 25 controls. Technicians assessing telomere length were blinded as to study group assignment.

 

Participants in the intervention group came from the GEMINAL study and those in the external control group from the University of California, San Francisco (UCSF) MENS study. All were men with low-risk prostate cancer who had chosen active surveillance rather than conventional treatment. Both active and control groups were recruited with the same selection criteria: pathology-confirmed prostate cancer; prostate-specific antigen (PSA) concentration 10 μg/L or lower (or lower than 15 μg/L if patients had benign prostatic hyperplasia or prostatitis); Gleason score of 6 or lower; a stage T1 or T2a tumor (according to the tumor, node, metastasis staging system); and 33% or less of biopsy cores and 50% or less of the length of a tumor-core positive for adenocarcinoma.

 

The lifestyle intervention included 4 components: diet high in whole foods, plant-based protein, fruits, vegetables, unrefined grains, and legumes and low in fat (approximately 10% of calories) and refined carbohydrates (take-home meals were provided to patients for the first 3 months of the intervention); moderate aerobic exercise (walking 30 min per day, 6 days per week); stress management (gentle yoga-based stretching, breathing, meditation, imagery, and progressive relaxation for 60 min daily); and increased social support (60 min support-group sessions once per week).

 

At each weekly session patients did an additional 1 h of moderate exercise supervised by an exercise physiologist, 1 h of stress-management techniques supervised by a certified stress-management specialist, 1 h of support group led by a clinical psychologist, and a 1 h lecture during dinner, generally from a dietitian, registered nurse, or physician. All members of the intervention staff were available to answer patients’ questions and to provide counselling at the weekly support sessions. Spouses and partners were encouraged to attend support sessions but were not required to do so.

 

After the first 3 months meetings were not compulsory, but patients could continue to meet on their own for two 4-h meetings per month for the duration of the study. A physician or nurse was on site during meetings and patients could request that other clinical staff attend or be available by telephone at these times, as needed.

 

Peripheral blood mononuclear cells (PBMCs) were used for assessment. Relative telomere length and telomerase enzymatic activity per viable cell were compared to baseline and related to the degree of lifestyle changes. Mean time between baseline and followup was 5.2 years (SD: 0.3) for the lifestyle intervention group and 4.1 years (SD: 1.1) for the control group.

 

Relative telomere length increased from baseline by a median of 0.06 telomere in the lifestyle intervention group, but decreased in the control group (–0.03 T/S units, –0.05 to 0.03, difference P=0.03). When data from the 2 groups were combined, adherence to lifestyle changes was significantly associated with relative telomere length after adjustment for age and the length of follow-up.

At 5 years, telomerase activity had decreased from baseline by 0.25 (–2.25 to 2.23) units in the lifestyle intervention group, and by 1.08 (–3.25 to 1.86) units in the control group (P=0.64), and was not associated with adherence to lifestyle changes (relative risk: 0.93, 95% CI: 0.72–1.20, P=0.57).

 

 

This study is a wonderful example of how research can be designed to assess a complete program of care, rather than a single intervention. I support such whole practice research as a means of assessing the relevance and effectiveness of ongoing practices. Such studies are not conducted often enough.

 

However, a valid criticism of such designs is the impossibility of knowing which aspect(s) of the intervention were effective. Was it one, or several parts, or a synergy between them? One thing we can do is attempt to tease out which aspects are effective by looking at prior research. In the case of this study, there is published research showing that singular aspects of the wholistic intervention may have influenced telomere length and telomerase activity.

 

For example, exercise,¹ meditation,² and tea drinking3 have all been shown to positively influence telomere length. A related issue is that Ornish is most well known for the ultra low-fat diet approach and I think many people reading the abstract or seeing the headlines about this study are going to gloss over the details of the “comprehensive lifestyle changes” in the title and equate the results with simply adopting a low-fat diet. While there is no way to determine if or how much the diet contributed to the outcomes, it is by no means the only dietary guidelines that affect telomere length. A classic Mediterranean diet (40% fat intake) has also been associated with telomere stability⁴ and has been shown to be superior to a low-fat diet for modification of long term cardiovascular risk factors.⁵

 

Ideally we want to help patients get the best result with the least amount of effort. I use the word/concept of 'efficiency' with my patients. I'm sure we all have our own way of saying something similar.

 

If you look at the Ornish program, adherence is not a low amount of effort, and compliance is not good. A study comparing Ornish, Atkins, Zone and Weight Watchers showed the Ornish diet had the worst retention rate: 50% of participants dropped out.⁶

 

If the results of the Ornish protocol—specifically the dietary components—are that much better than one can achieve with exercise or stress management alone, then it is worth the effort. However, if we can get the same or very similar results with less patient effort, we are likely to have much better patient compliance. It goes back to the whole-practice research issue. We can't really know what gave the effect; however if drinking 3 cups of green tea a day and meditating on loving kindness is close or equal to the Ornish protocol, I'll stick with recommending the tea and meditation. I'll get better compliance—and happier patients.

 

For more research involving integrative oncology, click here.