The Ornish Low Fat Vegetarian Diet, does it work?

Dr. Dean Ornish has done wonderful research in the area of cardiovascular disease and lifestyle intervention. His study on comprehensive lifestyle intervention (1) is often quoted to support a low fat vegetarian diet as treatment for cardiovascular disease. But his “Intensive lifestyle changes for reversal of coronary heart disease” included several components that would be expected to improve health and decrease cardiovascular risk independent of a vegetarian diet as will be discussed below.

Let’s review what this study did.

48 patients with diagnosed moderate to severe coronary artery disease were randomized to one of two treatment groups, an “intensive lifestyle change” (ILC) group or a “usual-care” (UC) control group. 28 patients were allocated randomly to the ILC group and 20 were allocated to the UC group. Out of 48 patients starting the study only 35 completed the study,   20 out of 28 in the ILC group completed the study and 15 out of 20 in the UC group completed the study.

The intensive lifestyle change group followed this program:

  • 10% fat whole foods vegetarian diet
  • daily aerobic exercise
  • stress management training (training in and daily performance of meditation and/or yoga)
  • smoke cessation (they quit smoking)
  • group psychosocial support (3 hour group therapy sessions)

At the start of the study only one patient in the ILC group was smoking and she quit. We do not know how many smokers were in the UC group or how many quit. (I consider that a deficiency of this study. Because smoking is such a significant determinant of cardiovascular outcome, details of smoking at start and end of the study for both groups should have been reported)

At the end of five years the intensive lifestyle change group demonstrated an average 3.1% absolute reduction in the coronary artery blockage as measured by coronary arteriograms (or to put it another way, the diameter of the blocked coronary arteries increased by 3.1%). The usual care group (receiving cholesterol lowering statin drugs) showed an average 2.3% absolute increase in the coronary artery blockage (2.3% reduction in diameter). These are not huge changes or differences but they were measurable and statistically significant.

Twenty five total  “cardiac events” occurred in the 28 patients randomized to the intensive lifestyle change group over the five years and 45 cardiac events occurred in the 20 patients randomized to the “usual care” group (receiving cholesterol lowering statin drugs). But this was due to differences in the number of hospitalizations and angioplasties. There was no statistically significant difference in the number of deaths, heart attacks or coronary artery bypass surgeries.

By the end of the study 2 patients in the ILC group had died compared to 1 death in the usual care group but as mentioned above, this difference was not statistically significant.  We do not know how many deaths occurred in the 8 patients who dropped out of the treatment group or in the 5 patients who dropped out of the usual care group, nor do we know any of the other outcomes for the drop-out patients.

So there were no lives saved by the intensive lifestyle change program and no reduction in the number of heart attacks. In fact the ILC group had 2 deaths compared to 1 in the usual care group.

What does this all mean and why has the Ornish Diet attracted so much attention.?

First, I would suggest that the demonstrated benefits (reductions in the number of angioplasties and hospitalizations) are likely explained by the following parts of the lifestyle changes.

  1. stress reduction training and implementation (meditation and yoga)
  2. elimination of manufactured trans-fats from the diet
  3. elimination of unhealthy pro-inflammatory excess omega six fats (vegetable oils) from the diet
  4. elimination/reduction of processed carbohydrates and sugar.

Although the intensive lifestyle intervention included regular exercise the data show no significant difference in times per week or hours per week of exercise at the end of the study between the two groups.

The big difference was in stress management. The ILC group averaged practicing meditation and/or yoga 5 times per week (48 minutes per day) versus less that once per week (8 minutes per day) in the usual care group.

Stress reduction is a major issue in any disease and in particular in cardiovascular disease.

Several studies have demonstrated that the daily practice of meditation  improves immune function, increases telomerase activity, reduces inflammatory markers, and reduces circulating stress hormones (cortisol and epinephrine) independent of dietary changes.
Meditation has also been observed to improve “endothelial function”, the ability of the cells that line arteries to respond to changes in demand. (2,3,4,5,6,7)

Here is a press release from the American Heart Association 13 November 2012. (8)

“African Americans with heart disease who practiced Transcendental Meditation regularly were 48 percent less likely to have a heart attack, stroke or die from all causes compared with African Americans who attended a health education class over more than five years, according to new research published in the American Heart Association journal Circulation: Cardiovascular Quality and Outcomes.

Those practicing meditation also lowered their blood pressure and reported less stress and anger. And the more regularly patients meditated, the greater their survival, said researchers who conducted the study at the Medical College of Wisconsin in Milwaukee.”

I believe the major benefit of the interventional program was from the stress reduction and the elimination of three major dietary sources of trouble (trans-fats, excess omega 6 fats from processed-refined vegetable oils, and refined carbohydrates-sugar)

I have already discussed in other posts the problems associated with excess omega 6 fats and refined carbohydrates-sugar relative to cardiovascular risk. (9,10,11)

There is little controversy that elimination/reduction in trans-fats produces benefit. (12,13,14)

All three of these changes were essential to the whole foods approach of the intervention group.

I have also discussed the lack of data to support the contention that saturated fat from animal sources of protein contributes to cardiovascular disease. (15, 16))

I remain a strong proponent of a whole foods diet that includes a variety and abundance of organic vegetables and fruits, nuts, pastured grass-fed meat, fresh wild seafood, free-range organic poultry and eggs from that kind of poultry.  This diet represents the foods we have evolved to eat, free from added sugar, hormones, antibiotics, pesticides. This dietary approach also produces a healthy balance of omega 6 to omega 3 fatty acid as well as a significant improvement in the ratio of potassium to sodium.

Stress reduction should be an essential part of our lives and data on this aspect of health will be discussed in future posts. References for this discussion appear below.

Peace,

BOB Hansen MD

REFERENCES:

1. JAMA Network | JAMA | Intensive Lifestyle Changes for Reversal of Coronary Heart Disease

2. Intensive meditation training, immune cell telomerase activity, and psychological mediators.

3. Can meditation slow rate of cellular aging? Cognitive stress, mindfulness, and telomeres.

4. A pilot study of yogic meditation for family dementia caregivers with depressive symptoms: effects on mental health, cognition, and telomerase activity.

5. Meditation Improves Endothelial Function in Metabolic Syndrome, American Psychosomatic Society (APS) 69th Annual Scientific Meeting: Abstract 1639. Presented March 10, 2011.

6. Alterations in brain and immune function produced by mindfulness meditation.

7. Adrenocortical activity during meditation.

8. Meditation may reduce death, heart attack and stroke in heart patients | American Heart Association

9. Polyunsaturated fat, Saturated fat and the AHA

10, Lose weight, control blood sugar, reduce inflammation

11. Sugar, a serious addiction

12. The negative effects of hydrogenated trans fats and what to do about them.

13. Trans fats in America: a review of their use… [J Am Diet Assoc. 2010] – PubMed – NCBI

14. FDA to Ban Trans Fats in Foods – US News and World Report

15. saturated fat | Practical Evolutionary Health

16. Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease.

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