People may be able to lose weight and body fat by eating a diet rich in fish or by taking fish oil supplements, said the author of an animal study being presented Sunday, June 3, at The Endocrine Society’s 89th Annual Meeting in Toronto.

Dr. James Levy of McGuire Veterans Affairs (VA) Medical Center in Richmond, Va., and a professor of medicine at Virginia Commonwealth University, looked at the effect of dietary fish oil on mice. The encouraging results have led his research team to begin similar studies in humans, he said.

For 10 weeks, the researchers fed mice a diet enriched with fish oil or lard, or regular mouse chow. The fish oil or lard made up 45 percent of the total calories. Even though all the animals ate the same number of calories, mice fed fish oil weighed less and had about 50 percent less body fat than the other mice. When Levy and colleagues gave the lard-fed mice the fish oil diet, they too lost a large amount of weight and body fat. By performing cultures of fat cells, they found that omega-3 (also called n-3) fatty acid, a component of fish oil, reduces body fat by enhancing heat production (expenditure of calories) and preventing lipids (fat in the blood) from being stored in fat cells.

Omega-3 fatty acids already are known to have several health benefits in people, including on heart health. These polyunsaturated fatty acids are found in fish such as tuna, salmon, lake trout and sardines.

The VA Scientific Merit Review Board funded this work.

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