The latest study to explore the slippery question of whether eating fish reduces the risk of heart disease found that it does - in modest quantities and for a certain type of the illness.
The study found that people who ate the equivalent of 3 ounces of salmon a week were only half as likely to be stricken with cardiac arrest as those who ate no fish.
Results are published in today’s issue of The Journal of the American Medical Association.
The findings may seem to conflict with a well-publicized study this spring by Harvard researchers, who found that men who ate fish several times a week were just as likely to have heart trouble as those who ate fish once a month.
“(But) we view these results as complementary and not in conflict with earlier findings,” said the lead author of the new study, Dr. David S. Siscovick of the University of Washington in Seattle.
The studies differed in two key ways, Siscovick said. The Seattle study focused on cardiac arrest rather than overall heart disease, which was the chief concern of the Harvard study.
Also, the Seattle study explored the value of eating some fish compared to eating none, rather than the Harvard report’s focus on eating more versus eating less.
In the new study, “modest” amounts of seafood containing two key omega-3 oils were sufficient, he said.
The oils are unique to fish, and are especially plentiful in salmon, herring, mackerel and anchovies.
Two 3-ounce servings of albacore tuna provide as much of the oils as one 3-ounce serving of salmon.
No one knows why omega-3 oils might prevent cardiac arrest, but one theory is that they may help regulate the movement of chemical compounds called electrolytes - calcium, potassium, sodium and others - in and out of cells.