Reduce heart attack risk and blood pressure, studies show
MONDAY, July 7 (HealthDay News) -- High intake of the omega-3 fatty acids in oily fish and vegetable cooking oils appear to help prevent heart attacks, while the omega-6 fatty acids in vegetables and nuts help keep blood pressure low, two international research teams report.
A study in Costa Rica found that high intake of omega-3 fatty acids reduced the risk of heart attack by 59 percent, said a report published in the July 8 online issue of Circulation.
In the Costa Rican study, "we compared those subjects who had heart attacks with those who did not have heart attacks," said study author Hannia Campos, a senior lecturer in nutrition at the Harvard School of Public Health. They had participants fill out food questionnaires and also analyzed body fat samples to determine levels of alpha-linolenic acid, a major omega-3 fatty acid.
A number of other studies have shown that high intake of omega-3 fatty acids is associated with lower risk of death from cardiovascular disease. This is the first study to look at its association with heart attack risk, Campos said.
"We found that the relationship is not completely linear," she said. "It plateaued after a certain level of intake. After that, higher levels do not mean increased protection."
The protective level turned out to be surprising low -- the amount in two teaspoons of soybean oil or canola oil, half a teaspoon of flaxseed oil or six to 10 walnut halves.
That protective effect could be detected, because the people in the Costa Rican study have a low level of omega-3 fatty acids in their diet, Campos said. "Their overall intake of fish is very low, much lower than in the United States, and the fish they eat are tropical, which are not as fatty as cold-water species," she said.
The high blood pressure study, reported in the July 8 online issue of Hypertension
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