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Omega-3s and Old Age: Fish Oil and Telomere Length
Abstract & Commentary
By Russell H. Greenfield, MD, Editor
Synopsis: Results of this longitudinal observation study reveal that, in people with stable coronary artery disease who were followed for 5 years, baseline levels of omega-3 fatty acids were inversely related to leukocyte telomere length, the latter a unique marker of aging. The authors conclude that high omega-3 fatty acid levels may protect against cellular aging. The study was well done, but the results may not be widely generalizable.
Source: Farzaneh-Far R, et al. Association of marine omega-3 fatty acid levels with telomeric aging in patients with coronary heart disease. JAMA 2010;303:250-257.
The researchers behind this prospective cohort trial sought to determine whether omega-3 fatty acid levels (n-3 levels) were associated with temporal changes in leukocyte telomere length over 5 years in outpatients with known coronary artery disease (CAD). Subjects were recruited from the Heart and Soul Study (a prospective cohort trial examining the influence of psychosocial factors on cardiovascular events in stable CAD). A total of 1,024 subjects enrolled in the study by 2002. At baseline, demographic information was collected, exercise capacity was determined, medication use detailed, and waist and hip circumference measurements performed. At the same time, participants had blood drawn for lipids and C-reactive protein, and measurements of n-3 levels and baseline telomere length performed. Resting 2-D echocardiography and Doppler examination were also performed, and left ventricular ejection fraction calculated.
Five years later all participants were invited to return for repeat examination. Complete data were available for evaluation on a total of 608 subjects with a median follow-up of 6 years (range, 5.0-8.1 years). Subjects and their n-3 levels were categorized by quartiles. In the quartile analysis, there was no significant association between baseline n-3 levels and baseline telomere length; however, baseline n-3 levels were positively correlated with 5-year change in telomere length. Subjects in the lowest quartile of n-3 levels experienced a decrease in telomere length of 0.13 T/S units, whereas those in the highest quartile experienced a decrease of only 0.05 T/S units (P < 0.001 for trend). In the unadjusted linear regression model, higher baseline log n-3 levels were associated with an increase in absolute telomere length over time. This association withstood sequential adjustment for a wide variety of potential confounding factors.
A total of 45% of subjects exhibited > 10% reduction in telomere length. Each 1-SD increase in baseline log n-3 level was associated with a 19% decrease in the odds of telomere shortening. After adjustment for potential confounders, each 1-SD increase in baseline log n-3 level was associated with a 32% decrease in the odds of telomere shortening.
The authors conclude that baseline levels of n-3s were inversely associated with telomere attrition over 5 years, an association that was linear and persisted after adjustment for potential confounders; thus, they say, n-3s may protect against cellular aging in people with stable CAD.
Most professionals, even most of the lay public, are aware of the potential health benefits associated with regular consumption of cold water fish or fish oil supplements. Published data strongly suggest a protective effect against second acute coronary events, dysrhythmias, elevated triglyceride levels, and vascular inflammatory changes, not to mention potentially beneficial effects in other clinical settings. But what sets this study apart is the measured effect on telomere length, a unique marker of aging that a growing number of experts seem to have confidence in. The mechanism of action of n-3s remains unknown at this time, but the conclusion seems inescapable that n-3s help modulate aging and age-related dysfunction. The current study utilized multivariable analysis and successfully discounted potential confounders, but as the authors note, there are many influences on telomere length beyond n-3s. One significant shortcoming the majority of subjects were male.
The results of this study further underscore the importance of omega-3 fatty acids in the prevention and treatment of CAD, but keep in mind the results represent an observation, not necessarily cause and effect.