Eating fish a few times a week significantly cuts the risk of death from a heart attack or other heart problems, two new studies published on Tuesday show, adding to a growing body of evidence that oils in fish are good for you.
Both studies are based on long-term monitoring of the health of medical professionals and the findings are important because half the people who suddenly collapse and die of a heart attack do not have a history of heart problems.
In one of the studies, published in Thursday's New England Journal of Medicine , researchers found that the risk of sudden death from a heart attack decreased by as much as 81 per cent for people who ate fish regularly.
The new results from the Physicians Health Study, an ongoing evaluation of 22,000 male doctors that began in 1982, looked at men with no known heart problems.
The New England Journal released the study a day early because the Journal of the American Medical Association was publishing similar research.
In that study, researchers at the Harvard School of Public Health said women who eat more fish rich in omega-3 fatty acids are at lower risk of developing or dying of coronary heart disease.
The finding was based on data from an ongoing study of more than 80,000 nurses whose health has been tracked for years.
"We observed a significant inverse association between fish and omega-3 fatty acid consumption and incidence of major coronary heart disease events, (and) deaths in particular, through a 16-year follow-up," the study said.
The New England Journal study, led by Dr Christine Albert, an epidemiologist at Brigham and Women Hospital in Boston, measured levels in the blood of the long-chain n-3 fatty acids, which are the type found in fish, especially fatty fish like salmon, mackerel, bluefish, swordfish and arctic char.
"The men with the higher fatty acid levels had a markedly lower risk of dying of heart disease. Specifically, they had a lower rate of sudden death," Albert told Reuters.
She said the finding supports earlier research suggesting that "these fatty acids might quiet the cells in the heart so when someone experiences a heart attack or some other kind of cardiac disease," the heart resists adopting a fatal rhythm, giving patients more time to seek treatment.
The study "is yet another addition to the growing body of evidence" that fish consumption "may provide protection against sudden death from cardiovascular causes," said Dr Irwin Rosenberg of Tufts University in a Journal commentary.
Albert said the doctors, on average "ate about one to four meals of fish per week. There's a lot of evidence from other studies that only a small amount of fish is needed. The American Heart Association recommends two meals per week."
Rosenberg said there are probably other benefits to eating fish. It may lead to a healthier immune system, better triglyceride levels, and lower blood pressure.