July 28, 2006 -- Eating fish like tuna or salmon one or twice a week can help older hearts keep their rhythm and reduce the risk of sudden cardiac death.
"The good news is that we're not talking about a large amount of fish intake, or fish oil supplements, but rather modest fish intake, one to two servings per week," says Dariush Mozaffarian, MD, DrPH, cardiologist and instructor of medicine at Harvard Medical School, in a news release. "But that modest intake may have important benefits."
Researchers say it's the first large-scale study to look at the effect of fish and fish oil consumption on the electrical function of the heart.
Fish Helps Heart Rate
In the study, published in the Journal of the American College of Cardiology, researchers analyzed dietary information on 5,096 men and women age 65 and over who participated in a large heart-health study from 1989-1990.
Researchers then compared the participants' fish-eating habits to their electrocardiogram (ECG or EKG) test results. They divided the participants into five groups depending on the amount of tuna or other baked/broiled fish intake they reported over the previous year.
The results showed eating tuna or other baked or broiled fish in the group of participants who reported eating the most, compared to the group who ate the least, appeared to improve the electrical function of the heart in at least three ways, including:
- Lowering the resting heart rate.
- Slowing the time between when the heart is signaled to pump blood and when the pumping occurs.
- Reducing the risk of the heart's electrical system not resetting properly after each heartbeat.
"In contrast to intake of tuna or other broiled or baked fish, intake of fried fish had no association with the heart's electrical parameters," says Mozaffarian. "Previously, we have seen that intake of fried fish -- which in the U.S. are most often commercially sold fish burgers or fish sticks -- is not associated with blood levels of omega-3 fatty acids. This suggests that it may be the omega-3 fatty acids in tuna and other broiled or baked fish that are having a positive impact on the heart's electrical parameters."
Fish rich in omega-3 fatty acids include tuna, salmon, lake trout, mackerel, and herring.