A new study by the University of Pittsburgh Graduate School of Public Health found consuming high amounts of fish oil protects the heart from disease. The findings are being published in the March 6 issue of the journal Heart.

Researchers at U Pitt worked with scientists in Japan, Philadelphia and Hawaii to study 300 men over the course of five years, tracking factors affecting cardiovascular health such as cigarette smoking, alcohol consumption, high blood pressure, diabetes rate and cholesterol in the blood.

After accounting for these risk factors, it was revealed U.S. men had "three times the incidence of coronary artery calcification" compared to the Japanese men.

The levels of marine-derived omega-3 fatty acids in the blood of the Japanese men, meanwhile, were more than 100 per cent higher than the levels in the white men.

"Multiple studies have looked at the effect of fish oil on cardiovascular health, with mixed results," said lead author Dr. Akira Sekikawa,  associate professor of epidemiology at Pitt Public Health.

"Previous studies investigated substantially lower intake of omega-3 fatty acids than what people in Japan actually get through their diet. Our study seems to indicate that the level of marine-derived omega-3 fatty acids consumed must be higher than previously thought to impart substantial protection."

Marine-derived omega-3 fatty acids are found in krill, squid and fish, particularly oily fish. Such fatty acids can reduce inflammation and the formation of fatty plaques in arteries.

Japanese people eat nearly 100 grams' worth of fish daily, while the average American consumes 7 to 13 grams of fish a day, or about one serving per week.

"The vast difference in heart disease and levels of marine-derived omega-3 fatty acid are not due to genetic factors," said Sekikawa.

"When we look at Japanese Americans, we find that their levels of coronary artery calcification are actually higher than that of the rest of the U.S. population."

"I am not encouraging Americans to start consuming massive amounts of fish, which may have harmful contaminants, such as mercury, in their flesh," he continued. "However, our findings indicate that it is worthwhile to take another look at the effect of marine-derived omega-3 fatty acids on heart disease, particularly when consumed at higher rates than previously investigated."