Developments in Brief : Fish Oil Benefits Shown in Monkeys

Fish oil fed to rhesus monkeys blocks hardening of the arteries induced by high-fat foods, researchers reported at a American Heart Assn. meeting.

In a finding that may have major implications for the human diet, University of Chicago scientists said their study is the first to demonstrate that fish oil directly reduces cholesterol buildup in primates, adding to a growing body of evidence that suggests a diet rich in fish can help prevent heart disease.

“It looks great,” researcher Harry Davis said. “We were very, very excited by this.”

But he cautioned against taking pure fish oil. “Right now I would recommend eating more fish. But I wouldn’t go so far as saying you should go and buy those fish oil supplements that are available. I’d say if you followed (the American Heart Assn.’s) general diet, lowering total cholesterol and fatty foods, and eat more fish, you’ll be doing all right.”

In their research, Davis and his colleagues fed three groups of monkeys diets combining fish oil with coconut oil, “one of the most atherogenic food fats in numerous species of animals.”

Monkeys fed only coconut oil had plaque buildup covering 79% of their main heart artery, while monkeys on diets containing equal amounts of coconut and fish oils showed 48% plaque. Animals fed a mixture containing more fish oil than coconut oil had only 36% buildup.

Another study presented at the Dallas meeting found that substances in fish oils, called Omega-3 fatty acids, appear to lower the melting point of cholesterol and might keep it from accumulating in the bloodstream.

Davis said this could explain the beneficial nature of fish oil, but not necessarily. “There’s probably 10 or 15 mechanisms I could propose for this,” Davis said. “But it doesn’t much matter how it works, as long as it works.”