Are the benefits of long-chain polyunsaturated omega 3 fatty acids (n-3 PUFA) on heart disease and total mortality clear-cut? There are thousands of studies to support their importance for cardiovascular health, and many authoritative groups, including the American Heart Association, advise eating at least two fish meals/week (preferably oily) in order to reduce risk of cardiovascular disease. 
 
Population studies, mostly relying on self-reported intakes, have consistently found omega 3 intakes reduce risk of coronary heart disease (CHD) death. However, in randomized controlled trials (RCTs) of omega 3 supplementation and CHD death, results have been mixed. The discrepancies have been attributed in part to the fact that RCTs used subjects with established CHD, limiting their ability to apply the results to the general, healthy population.
 
In order to clarify effects of n-3 fatty acids on all-cause and CHD death in healthy people, Mozaffarian and colleagues examined total and individual n-3 PUFA blood levels with total and cause-specific mortality among healthy older adults not taking omega 3 supplements. In a prospective cohort study across four U.S. communities, 2,692 older U.S. adults (average age 74 years), without CHD, stroke or heart failure at baseline (1992), provided blood samples to obtain phospholipid fatty acid levels and cardiovascular risk factors. Relationships with total and cause-specific mortality and incident fatal or nonfatal CHD and stroke through 2008 were assessed.
 
After adjustment, higher plasma levels of n-3 PUFA [eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA)] biomarkers were associated with lower total mortality, such that those with the highest levels of individual and total n-3 PUFA had a 27% reduction in total mortality compared to those with the lowest n-3 PUFA levels. Consistent with previous studies, lower risk was largely attributable to fewer cardiovascular deaths, with the highest n-3 PUFA levels resulting in 48% reduction in risk of CHD death. These mortality differences corresponded to an average of 2.2 years of additional life expectancy compared to those in the lowest n-3 PUFA quintile. 
 
So, how much do these blood levels mean in terms of diet? The researchers note their findings support average target intakes in the range of 250-400 mg EPA+DHA daily. This is achievable with the two fatty fish meals per week, as recommended by the American Heart Association, Dietary Guidelines for Americans and American and Canadian Dietitians’ Associations. It is also consistent with intakes recommended by ISSFAL and other international authoritative bodies. 
 
As the researchers concluded, “few interventions substantially alter total mortality later in life … the results highlight the potential benefits of modest n-3 PUFA intake for primary prevention in older adults.” 
 
Are you getting your two fish meals weekly? If not, consider an EPA/DHA omega 3 supplement or fortified foods to ensure you are getting enough of these vital nutrients to promote overall health as you age.
 
Citation
Mozaffarian D Lemaitre RN King IB Song X Huang H Sacks FM Rimm EB Wang M and Siscovick DS (2013). Plasma Phospholipid Long-Chain ω-3 Fatty Acids and Total and Cause-Specific Mortality in Older Adults: A Cohort Study. Ann Intern Med 158:515-525. http://www.ncbi.nlm.nih.gov/pubmed/23546563