By Craig Weatherby
It’s long been clear that omega-3s from seafood are good for the heart.
Now, a 16-year study among adults aged 69 to 79 links higher blood omega-3 levels to reduced risk of death.
Those who had the highest omega-3 blood levels lived, on average, 2.2 years longer than those with lower levels.
And the volunteers with higher omega-3 blood levels were 27 percent less likely to die within 16 years.
Much of the added longevity came from a 35 percent drop in the risk of dying from heart disease.
Importantly, the participants got all of their omega-3s from fish, since none took omega-3 supplements.
Study takes novel, reliable tack
Previous studies linked fish-rich diets to a lower risk of dying from heart disease.
But most relied on estimates of omega-3 intake based on people’s claims about their fish intakes … and didn’t measure their omega-3 blood levels.
(Blood testing greatly increases the reliability of statistical correlations between dietary nutrients and health.)
And we’ve lacked blood-based studies that looked for statistical links between fish-rich diets and other causes of death or total mortality rates.
“Although eating fish has long been considered part of a healthy diet, few studies have assessed blood omega-3 levels and total deaths in older adults,” said lead author Dariush Mozaffarian, M.D., professor of epidemiology at the Harvard School of Public Health (HSPH).
As he said, “Our findings support the importance of adequate blood omega-3 levels for cardiovascular health, and suggest that later in life these benefits could actually extend the years of remaining life.” (HSPH 2013)
Would fish oil supplements work as well as a fish-rich diet?
Most clinical trials testing fish oil supplements show heart benefits, and supplements seem very wise for people who eat little or no seafood.
And it can’t hurt regular fish-eaters to take some omega-3 fish oil as insurance … especially given the blocking effect of America’s omega-6 overload.
For more on that overlooked but truly critical subject, see “Heart Risks Raised by Omega-6 Excess”, “America's Sickening Omega Imbalance”, and “Using our Omega 3/6 Balance Scores”.
Landmark study compared omega-3 blood levels to longevity
The study was the first to compare omega-3 blood levels to total deaths and specific causes among adults aged 69 to 79 years (Mozaffarian D et al. 2013).
The team included scientists from the Harvard School of Public Health (HSPH) and the University of Washington.
They sought to paint a clearer picture by testing the omega-3 blood levels of adults who were not taking fish oil supplements.
Harvard and UW scientists examined data from the Cardiovascular Health Study (CHS) study, in which 2,692 U.S. adults aged 69 to 79 were followed for 16 years.
The study participants came from communities in North Carolina, California, Maryland, and Pennsylvania.
All were generally healthy at the outset, without diagnosed coronary heart disease (CHD), stroke, or heart failure.
At the beginning and regularly during the next 16 years, participants had blood drawn, underwent physical examinations and diagnostic testing, and were questioned about their health status, medical history, and lifestyle.
The researchers measured the levels of all three major omega-3s – EPA, DHA, and DPA – in participants’ blood samples.
After adjusting for demographic, cardiovascular, lifestyle, and dietary factors, they found that the three omega-3s—both individually and combined—were associated with a significantly lower risk of mortality.
Omega-3 DHA was linked to a 40 percent drop in the risk of death from coronary heart disease … including a 45 percent drop in the risk of death caused by disturbed heart rhythms (arrhythmias).
Omega-3 DPA was most strongly associated with lower risk of stroke death, and EPA was most strongly linked to a lower risk of non-fatal heart attack.
None of the three omega-3 fatty acids were strongly linked to changes in the risk of other, non-cardiovascular causes of death.
Support for the study came from the National Heart, Lung, and Blood Institute (NHLBI) and the Office of Dietary Supplements of the National Institutes of Health.
Harvard School of Public Health (HSPH). Higher blood omega-3s associated with lower risk of premature death among older adults. April 2, 2013. Accessed at http://www.hsph.harvard.edu/news/press-releases/higher-blood-omega-3s-associated-with-lower-risk-of-dying-among-older-adults/
Joensen AM, Schmidt EB, Dethlefsen C, Johnsen SP, Tjønneland A, Rasmussen LH, Overvad K. Dietary intake of total marine n-3 polyunsaturated fatty acids, eicosapentaenoic acid, docosahexaenoic acid and docosapentaenoic acid and the risk of acute coronary syndrome - a cohort study. Br J Nutr. 2010 Feb;103(4):602-7. doi: 10.1017/S0007114509992170. Epub 2009 Oct 14.
Lemaitre RN, King IB, Mozaffarian D, Kuller LH, Tracy RP, Siscovick DS. n-3 Polyunsaturated fatty acids, fatal ischemic heart disease, and nonfatal myocardial infarction in older adults: the Cardiovascular Health Study. Am J Clin Nutr. 2003 Feb;77(2):319-25.
Mozaffarian D, Lemaitre RN, King IB, Song X, Huang H, Sacks FM, Rimm EB, Wang M, Siscovick DS. Plasma Phospholipid Long-Chain ω-3 Fatty Acids and Total and Cause-Specific Mortality in Older Adults: A Cohort Study. Ann Intern Med. 2013 Apr 2;158(7):515-25. doi: 10.7326/0003-4819-158-7-201304020-00003.
Mozaffarian D, Lemaitre RN, King IB, Song X, Spiegelman D, Sacks FM, Rimm EB, Siscovick DS. Circulating long-chain ω-3 fatty acids and incidence of congestive heart failure in older adults: the cardiovascular health study: a cohort study. Ann Intern Med. 2011 Aug 2;155(3):160-70. doi: 10.1059/0003-4819-155-3-201108020-00006.
Wu JH, Lemaitre RN, King IB, Song X, Sacks FM, Rimm EB, Heckbert SR, Siscovick DS, Mozaffarian D. Association of plasma phospholipid long-chain ω-3 fatty acids with incident atrial fibrillation in older adults: the cardiovascular health study. Circulation. 2012 Mar 6;125(9):1084-93. doi: 10.1161/CIRCULATIONAHA.111.062653. Epub 2012 Jan 26.