The rapid, weak contractions produced by A-fib slow the flow of blood in the atrium, which may cause it to pool, become sluggish, and form clots that can travel to the brain and cause a stroke (NINDS 2012).
Now, a new study from the Harvard School of Public Health indicates that DHA – one of two major omega-3s in fish oil, along with EPA – may help prevent A-fib.
Omega-3 DHA is concentrated in heart muscles' cell membranes, and there's some evidence that adding more – from dietary fish or fish oil – helps keep these cells on an even rhythmic keel.
Extra-reliable study links higher omega-3 levels to a 30% drop in A-fib risk
An unusually reliable study in more than 3,000 Americans found that who had the highest total omega-3 or omega-3 DHA blood levels were about 30 percent less likely to develop A-fib (Wu JH et al. 2012).
Senior author Dariush Mozaffarian, M.D., expressed the important implications of his team's finding: “A 30 percent lower risk of the most common chronic arrhythmia in the United States population is a pretty big effect.” (Grens K 2012)
Most health-nutrition research relies on diet questionnaires to estimate people's nutrient intakes and compare those to their health status over time.
Of course, these are inherently subject to errors in participants' memories … and in researchers' estimates. As Dr. Mozaffarian noted, “Any given fish species can vary in its omega-3s by 10-fold.” (Grens K 2012)
Unlike most health-nutrition research, this new Harvard study measured people's blood levels of omega-3s.
The analysis involved 3,326 American men and women aged 65 or older who were free of A-fib or congestive heart failure (which can promote A-fib), and measured their blood levels of omega-3 EPA, DPA, and DHA .
After 14 years, the one-quarter of the volunteers who had the highest total omega-3 or the highest omega-3 DHA blood levels were 25-30 percent less likely to develop A-fib, compared to the one-quarter with the lowest omega-3 levels (Wu JH et al. 2012).
To be exact, those with the highest total omega-3 (EPA+DPA+DHA) levels were 29 percent less likely to develop A-fib, while those with the highest DHA levels were 23 percent less likely to develop A-fib.
In contrast, having higher blood levels of either EPA or DPA wasn't associated with a reduced risk of developing A-fib.
A recent study from Finland, whose authors' also measured the omega-3 levels in participants' blood, found a similar reduction in the risk of A-fib among those with the highest levels. (See “Omega-3 May Deter Common Heart-Rhythm Disorder
” in our “Prior signs”sidebar.)
Results hold implications for prevention and more
Many, if not most, cases of A-fib go undiagnosed, making prevention even more important.
This fact prompted a hopeful comment from Dr. Gilbert Ross of the American Council on Science and Health … which usually takes a skeptical stance toward supplements.
As Dr. Ross said, “A 30 percent reduced risk of atrial fibrillation, perhaps linked to higher amounts of DHA consumption, is impressive. More Americans should be following the U.S. Department of Agriculture guidelines by consuming fish at least twice weekly.” (ACSH 2012)
We've no argument with common sense, evidence-based advice from any quarter!
American Council on Science and Health (ACSH). Omega-3's for heart rhythm. February 2, 2012. Accessed at http://www.acsh.org/factsfears/newsID.3364/news_detail.asp
Grens K. Omega-3s tied to lower risk of heart arrhythmia. Reuters Health, February 1, 2012. Accessed at
National Institute of Neurological Disorders and Stroke (NINDS). Atrial Fibrillation and Stroke Information. Accessed February 6, 2012 at http://www.ninds.nih.gov/disorders/atrial_fibrillation_and_stroke/atrial_fibrillation_and_stroke.htm
Wu JH, Lemaitre RN, King IB, Song X, Sacks FM, Rimm EB, Heckbert SR, Siscovick DS, Mozaffarian D. Association of Plasma Phospholipid Long-Chain Omega-3 Fatty Acids with Incident Atrial Fibrillation in Older Adults: The Cardiovascular Health Study. Circulation. 2012 Jan 26. [Epub ahead of print]