According to a recent article in Circulation: Journal of the American Heart Association, researchers have found that healthy men who regularly ate fish had lower average heart rates. The study’s lead author Jean Dallongeville, M.D., Ph.D., of the department of epidemiology and public health at the Institut Pasteur de Lille in France indicates that these findings are particularly important because sudden death most often occurs in men without a known history of coronary heart disease also known as CHD.

This is currently the largest study of its kind and indicates that increased heart rate is a risk factor for sudden death. Sudden death occurs when the heart stops abruptly, a condition also known as cardiac arrest. Most cardiac arrest occurs when electrical impulses in the heart become rapid and/or chaotic.

Omega 3 fatty acids may prevent sudden death and fatal cardiovascular events by regulating the heartbeat and preventing irregular rhythms associated with sudden death. Cold-water fish such as salmon, tuna and mackerel are good sources of omega 3 fatty acids.

During the past 10 years, epidemiological studies have found an association between fish consumption and a decreased risk of CHD deaths and sudden death in healthy men and in those with known CHD. Short-term trials also found that fish oil supplements at a dose of about 1 gram a day reduced heart rate, diminished extra heartbeats and normalized heart rhythm in both healthy people and those at high risk of CHD.This is the largest study to look at fish consumption rather than fish oil supplements as compared to the heart rate in healthy men.

Researchers studied 9,758 men, ages 50 to 59, from Lille, France and Belfast, Ireland. They were all free of coronary heart disease and had been recruited through the World Health Organization’s MONICA (Monitoring Trends and Determinants in Cardiovascular Disease) centers. The men answered a survey about their diets, physical activity levels and other lifestyle factors. Blood samples were used to determine cholesterol and triglyceride levels and a subset of 407 men was tested to determine their blood levels of the omega 3 fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

The men were divided into groups according to their fish intake: less than once per week (27.3 percent), once per week (46.9 percent), twice per week (20.1 percent) and more than twice per week (5.7 percent). Adjusted heart rate ranged from 67.5 beats per minute in men who ate fish less than once a week to 65.6 beats per minute for those consuming fish more than twice a week. Heart rate decreased in a linear fashion across categories of fish consumption, even after adjusting for age, location, education level, physical activity, smoking and alcohol consumption. The researchers found an association between heart rate and blood levels of DHA, but not EPA.

They found no difference in fish consumption between men in the two countries, however, fish eaters were more educated, more physically active, drank alcohol less, and were less often smokers than non-fish eaters. Since the link between fish intake and heart rate was consistent in both countries, the link appears to be independent of lifestyle factors. The co-authors include: John Yarnell, M.D., Ph.D.; Pierre Ducimetière, Ph.D.; Dominique Arveiler, M.D., Ph.D.; Jean Ferrières, M.D., M.P.H.; Michèle Montaye, M.D.; Gérald Luc, M.D.; Aluns Evans, M.D., Ph.D.; Annie Bingham, Bernadette Hass, M.D.; Jean-Bernard Ruidavets, M.D., Ph.D.; and Philippe Amouyel, M.D., Ph.D.