Men's Health Women's Health Senior's Health Antioxidants Sports Nutrition Diet & Weight Loss Vitamins & Minerals Herbs Specialty Supplements Targeted Supplements Spa Products Anti-Aging Basics Body Systems Body Structure Book Store Pet Health My Recommendation My Favorite Articles Our Most Popular Specials Bargain Basement Brands

MSM

Health News Archive 380 - Heart
<<back to structure/function index

Omega-3 Fatty Acids in Fish Help Maintain Heart Rhythm

Eating tuna, other broiled or baked fish, or fish oil has a beneficial effect on the electrical system of the heart, which may help prevent life-threatening heart rhythm disorders, according to a new report.

Previous reports have linked fish intake with a reduced risk of sudden death and irregular heart beats, but the mechanisms responsible for this association were unknown. However, evidence from animal studies has suggested a direct effect from fish oil intake on the hearts electrical circuitry.

As reported in the Journal of the American College of Cardiology, Dr. Dariush Mozaffarian, of Harvard Medical School, Boston, and colleagues analyzed data from 5,096 adults enrolled in the Cardiovascular Health Study to investigate the link between dietary intake of fish omega-3 fatty acid and features seen on electrocardiograms.

The population-based study, which focused on cardiovascular disease risk factors, ran from 1989 to 1990 and involved subjects who were at least 65 years of age.

Intake of tuna or other broiled or baked fish at least once a week or intake of 1 gram/day fish oil was associated with a slower heart rate than was eating these fish less than once a month. Moreover, fish intake at least five times per week was associated with an even healthier heart rhythm. Consumption of marine n-3 fatty acids appeared to have similar effects. Intake of fried fish, which is high in omega-6 from the oil, was not associated with any ECG changes.

"Previously," Mozaffarian said in a statement, "we have seen that intake of fried fish -- which in the US are most often commercially sold fish burgers or fish sticks -- is not associated with blood levels of n-3 fatty acids. This suggests that it may be the n-3 fatty acids in tuna and other broiled or baked fish that are having a positive impact on the heart's electrical parameters." There are a number of good fish oils on the market, but one of the best new ways to get omega-3 fats is from krill oil.

Objectives

We evaluated the association between dietary fish intake and several cardiac electrocardiographic parameters in humans relevant to arrhythmic risk.

Background

Fish consumption may reduce the incidence of sudden death and atrial fibrillation, possibly related to anti-arrhythmic effects.

Methods

In a population-based study of 5,096 men and women, we evaluated cross-sectional associations between usual dietary fish intake and electrocardiographic measures of heart rate, atrioventricular conduction (PR interval), ventricular repolarization (QT interval), and ventricular conduction (QRS interval). Multivariate models were adjusted for age, gender, race, education, smoking, body mass index, diabetes, coronary heart disease, physical activity, and intakes of beef or pork, fried fish, fruits, vegetables, alcohol, and total calories.

Results

Consumption of tuna or other broiled or baked fish (comparing the highest to the lowest category of intake) was associated with lower heart rate (−3.2 beats/min, 95% confidence interval [CI] = 1.3 to 5.1; p trend <0.001), slower atrioventricular conduction (PR interval +7.2 ms, 95% CI = 1.4 to 12.9; p trend = 0.03), and substantially lower likelihood of prolonged QT (relative risk = 0.50, 95% CI = 0.27 to 0.95; p trend = 0.03). Tuna/other fish intake was not associated with ventricular conduction (p = 0.60). Findings were similar for estimated intake of marine n-3 fatty acids: a 1 g/day higher intake was associated with 2.3 beats/min lower heart rate (95% CI = 0.9 to 3.7), 7.6 ms longer PR interval (95% CI = 3.3 to 11.9), and 46% lower likelihood of prolonged QT (relative risk = 0.54, 95% CI = 0.33 to 0.88).

Conclusions

These findings in this large, population-based study suggest that dietary fish intake is associated with cardiac electrophysiology in humans, including heart rate, atrioventricular conduction, and ventricular repolarization, with potential implications for arrhythmic risk.

Source: Mozaffarian D, Prineas RJ, Stein PK, Siscovick DS. Dietary Fish and n-3 Fatty Acid Intake and Cardiac Electrocardiographic Parameters in Humans. Journal of the American College of Cardiology. Volume 48, Issue 3, 1 August 2006, Pages 478-484.

back to top