Omega-3 Fatty Acids Improve Heart Rate

VRP Staff

The mechanism by which omega-3 fatty acids may decrease the risk of sudden cardiac death in patients with heart disease may revolve around omega-3’s ability to affect the heart-rate-controlling vagus nerve, a new study shows.

The heart-protective effects of omega-3 fatty acids have been documented in epidemiologic and randomized controlled trials. Past studies have shown that omega-3 fatty acids decrease susceptibility to fatal arrhythmias, but the precise mechanism of action is not known.

In the current study, 18 men with a history of myocardial infarctions (heart attacks) and low ejection fractions (the percentage of the blood emptied from the ventricle during contractions) were randomized to placebo or omega-3 fatty acids (585 mg of docosahexaenoic acid and 225 mg of eicosapentaenoic acid) for two, four-month periods in a crossover design. In other words, one group of subjects received the placebo while another group received the omega-3 fatty acids; Four months later the placebo group was switched to omega-3 fatty acids and the omega-3 group to the placebo.

At the end of each period, heart rate, heart rate variability (a term that refers to the heart’s ability to self-regulate its own contractions), and rate of heart rate recovery after exercise were determined, as were effects on arterial compliance, blood pressure, cardiac function, and fasting serum levels of lipids and inflammatory markers.

Omega-3 fatty acids decreased resting heart rate from 73 +/- 13 beats per minute to 68 +/- 13 beats per minute and improved 1-minute heart rate recovery after exercise. Heart rate variability in the high-frequency band increased, but no change was noted in overall heart rate variability. There were no significant effects on blood pressure, arterial compliance, lipids, or inflammatory markers.

The researchers concluded that these changes are consistent with an increase in activity of the vagus nerve and “may in part explain the observed decrease in risk for sudden cardiac death seen with omega-3 fatty acid supplementation.”

Reference:
O’Keefe JH Jr, Abuissa H, Sastre A, Steinhaus DM, Harris WS. Effects of omega-3 fatty acids on resting heart rate, heart rate recovery after exercise, and heart rate variability in men with healed myocardial infarctions and depressed ejection fractions. Am J Cardiol. 2006 Apr 15;97(8):1127-30. Epub 2006 Mar 3.