A Word of Caution
There is a large gap between the conclusions of the paper, which sensibly state that the study was very small and needs to be replicated in larger populations, and Ornish's statements, which promise that aging can be reversed at the cellular level, seemingly for all people at all ages. Here are a number of reasons why you should be very cautious before drinking this Kool-Aid, despite its resemblance to the elixir of youth.
This was not a randomized trial. Patients in the treatment group agreed to intense and highly demanding lifestyle changes. They were compared with a group who had similar risk factors but who clearly did not share their high level of motivation. There is no way to know what other important differences might exist between the two groups.
This was a very small trial. The original 2008 trial enrolled 30 patients– there were no controls– and 24 patients had sufficient blood samples to assess telomerase activity. In the new report only 10 patients had adequate blood samples available for analysis. This severely limits the generalizability of the findings.
What caused the changes (if there were changes)? The Ornish program is famous for containing multiple interventions, including drastic reductions in dietary fat and sugar, significant increases in exercise , as well as yoga classes and group therapy. There is no way to know the relative importance, or lack of importance, of any of the individual components of his program.
It is entirely possible that other, completely different interventions would have a similar effect. Last spring a paper reported that telomere length increased in people who lost weight after 5 years on the Mediterranean diet, which is not a low fat diet and which is generally thought to be much more palatable than the extreme low-fat Ornish diet.
Finally, we should be extremely cautious about the use of surrogate endpoints. There is no doubt that telomere research represents one of the most significant research advances of the last generation. But it is far too early to know if measuring telomere length is a good way to assess the value of an intervention.'