Eating fish may reduce risk of sudden death

Eating more fish may help save your life, according to two new studies.

In one, researchers conclude that the fatty acids in fish can reduce the risk of sudden death from cardiac causes among men, even those without a history of heart disease. The other found that eating more fish lowers the risk of dying from coronary heart disease among women.

Cardiovascular (heart and blood vessel) disease is the leading killer of people in the industrialized world; it results in 250,000 sudden deaths each year in the United States alone. More than 50 percent of these sudden deaths kill people with no history of cardiac disease. It would be astounding if simply eating more of a food that many people consider delicious could keep more of them alive for a longer time.

Researchers at Harvard Medical School and Harvard School of Public Health have been following the health of more than 22,000 male doctors since 1982. They examined fatty acids from fish in the blood of 94 of these men who died suddenly and compared the results with 184 living men matched for age and how much they smoked. Those with the highest levels of fatty acids from fish in their blood had an 81 percent lower risk of sudden death than those with the lowest levels.

“Overall, the higher the amounts of omega-3 fatty acids climbed in blood samples, the greater sudden-death-risk was reduced,” said Christine Albert. Leader of the study, Albert works at Brigham and Women’s and Massachusetts General hospitals, both affiliated with Harvard Medical School. The results are reported in today’s issue of The New England Journal of Medicine.

The second study, conducted at the Harvard School of Public Health, followed 84,688 female nurses to see if a relationship exists between eating fish and the risk of heart disease. “Our research suggests that women can reduce their risk of heart disease by more than 30 percent by eating fish two to four times a week,” said Frank Hu, leader of the study and an associate professor of nutrition and cardiovascular disease.

During the 16 years of follow-up, Hu and his colleagues noted 484 deaths from heart disease and 1,029 non-fatal heart attacks. They found that, compared to women who ate fish less than once a month, those who ate it once a week had a 29 percent lower risk of coronary heart disease. Eating fish two to four times a week lowered the risk 31 percent. Those who ate fish five times a week had a 34 percent lower risk of heart disease, as well as a 45 percent lower risk of death from it.

Hu’s team reported their results in the current Journal of the American Medical Association.

Fish calms the heart

Of course, it’s not only eating fish that will save your heart. Compared to women who seldom ate fish, those who consumed it one to five times a week smoked less, exercised vigorously, and took aspirin and multivitamins regularly. They ate more chicken, fruits and vegetables, and less red meat.

Men who died suddenly in the Albert study were more likely to have high blood pressure, parents who had coronary artery disease before age 60, and drink more than six alcoholic drinks a week. They were also less likely to take a daily aspirin, and they drank less than one alcoholic drink a week.

Results of both studies add to a long list of evidence that eating unsaturated fatty acids from fish, especially species with dark meat such as salmon and mackerel, helps protect the heart. Inuits in Alaska and Greenland and Japanese people who live in fishing villages enjoy a much lower incidence of heart disease than do other people in North America and Europe. Fatty acids from seafoods are also a central element in the heart-friendly Mediterranean diet.

The Harvard studies, says Hu, “lend further support to dietary guidelines that recommend fish consumption twice weekly for prevention of coronary heart disease, the number one killer of men and women in the U.S.” Each year more than 500,000 Americans die of heart attacks caused by coronary heart disease, which results from narrowing of arteries that feed blood to the heart.

“Since more than 50 percent of people who die suddenly (from heart disease) have no signs or symptoms of the disease, we need to take preventive steps to protect that population,” adds Albert. “Eating more fish rich in omerga-3 fatty acids is one life style change that may offer great rewards for little risk.”

Both studies support the theory that omega-3 fatty acids calm and protect the heart from lethal rhythm disturbances and reduce cholesterol levels and blood clotting.

In an editorial accompanying the Albert article in The New England Journal of Medicine, Irwin Rosenberg a nutritionist at Tufts University in Boston, notes that eating fishy fatty acids is likely to have other beneficial effects. He mentions lowering blood fat levels, reducing clotting mechanisms and blood pressure, boosting the immune system, and aiding the development of the central nervous system by the transmission of fatty acids through breast milk.