The omega-3 fats in fish oil, touted for their heart-health benefits, may have a bonus for heart patients: slowing biological aging at the cellular level. In a study of patients with stable coronary artery disease, those with the highest blood levels of omega-3s also showed the least shortening of telomeres, a sign of biological rather than chronological aging. Patients with the lowest omega-3 levels, on the other hand, had the fastest rate of telomere shortening when researchers compared measurements from the start of the study to five years later.Several studies have shown increased survival rates among individuals with established cardiovascular disease who consume more omega-3 fatty acids from fish. But the mechanisms underlying this protective effect are not well understood.
| For new findings on how exercise may also affect telomeres and aging, see this issues Special Report. |
Telomeres are a structure at the end of a chromosome involved in the replication and stability of the chromosome. Genetic factors and environmental stresses can shorten the length of a telomere, so telomere length is becoming an emerging marker of biological age.Ramin Farzaneh-Far, MD, of the University of California-San Francisco, and colleagues looked at changes in telomere length among 608 outpatients recruited for the Heart and Soul Study. The scientists measured telomeres in blood cells called leukocytes, both at the beginning of the study and again after five years of follow-up.By measuring telomere length at two different times, Dr. Farzaneh-Far explained, we were able to see the speed at which the telomeres are shortening, and that gives us some indication of how rapidly the biological aging process is taking place in these patients. Telomere changes were compared to blood levels of the two most important omega-3s found in fish, DHA and EPA, taken at the studys start. Over five years, patients in the lowest one-quarter of DHA plus EPA saw more than two and a half times the telomere shortening of those with the most omega-3s. This suggests that these patients were aging faster than those with higher fish-oil levels, Dr. Farzaneh-Far noted.As omega 3 levels went up, on the other hand, the odds of telomere shortening went down. The relationship remained the same even after adjusting for factors such as demographics, cholesterol levels and blood pressure.The study wasnt designed to prove cause and effect, so its possible that heart patients who eat more fish simply have other healthy habits that are responsible for combating biological aging. The researchers speculated, however, that omega-3s may protect against oxidative stress or may increase the activity of an enzyme crucial to telomere duplication.They concluded, These findings raise the possibility that omega-3 fatty acids may protect against cellular aging in patients with coronary heart disease.While its not clear whether these findings extend to the general population, Dr. Farzaneh-Far added that the results underscore the recommendations of the American Heart Association that patients with known coronary heart disease consume about a gram of DHA plus EPA daily. Fatty fish is the preferred source-a 3-ounce serving of cooked salmon contains about 1.5 grams of DHA plus EPA-but the association advises that fish oil in capsule form could be considered as a source of DHA and EPA in consultation with your physician.TO LEARN MORE: Journal of the American Medical Association, Jan. 20, 2010; abstract at jama.amaassn.org/cgi/content/abstract/303/3/250. Fish 101, www.americanheart.org/presenter.jhtml? identifier=3071550.