An interesting article appeared in the April 2010 Nutrition Action Health Letter that reported on a study of 600 San Francisco area residents with heart disease. Those with the highest blood levels of the Omega-3 fats, DHA and EPA, had the least telomere shortening, while those with the lowest blood levels had the most shortening. This is important because telomeres are the end-sections of chromosomes that become shorter as we age, eventually triggering genes that bring about symptoms of aging. These results were independent of other factors that might affect risk, like blood pressure, body weight, smoking history and exercise participation. The health letter recommends eating fatty fish like salmon twice a week and the American Heart Association recommends that people with heart disease take one 1,000 mg fish oil capsule daily. More than 3,000 mg per day may cause bleeding.
NOTE: This was a cross-sectional study. More definitive conclusions about the effects of Omega-3 fats on telomeres would be gained from prospective studies in which half the subjects are randomly assigned to eat high Omega-3 diets for several years while the other half are assigned to eat low Omega-3 diets, and the effects on their telomere shortening are observed. Of course, it is still a good idea to eat fatty fish because of the abundant existing evidence of it's disease-deterring qualities. Also, some of the countries with the longest life spans have high percapita fish consumption.