Washington, July 29 (IANS) If you’re looking out for ways to minimise risk of heart disease, you could begin with a seafood-rich diet typically served in Japan. A lifetime of eating tuna, sardines, salmon and other fish appears to protect Japanese men against clogged arteries, independently of other cardiovascular risk factors, according to a new study.

Researchers have identified omega-3 fatty acids, found in fish oil, as the source of protection.

In the first ever study, researchers found that compared to middle-aged white men or Japanese-American men living in the US, natives of Japan had twice the blood levels of omega-3 fatty acids - a finding linked with low levels of atherosclerosis.

“The death rate from coronary heart disease in Japan has always been puzzlingly low,” said Akira Sekikawa, assistant professor of epidemiology at the University of Pittsburgh.

“Our study suggests that the very low rates of coronary heart disease among Japanese living in Japan may be due to their lifelong high consumption of fish.”

Japanese eat about three ounces of fish daily, on average, while typical Americans eat fish perhaps twice a week. Nutritional studies show that the intake of omega-3 fatty acids from fish averages 1.3 grams per day in Japan, as compared to 0.2 grams per day in the US.

Earlier studies by Sekikawa’s team showed that Japanese men had significantly less cholesterol build-up in their arteries when compared to white men living in the US-despite similar blood cholesterol and blood pressure readings, similar rates of diabetes and much higher rates of cigarette smoking.

The study enrolled 868 randomly selected men aged 40 to 49. Of these, 281 were Japanese men from Kusatsu, Shiga, Japan; 306 were white men from Allegheny County, Pennsylvania; and 281 were third- or fourth-generation Japanese-American men from Honolulu, Hawaii.

Sekikawa and colleagues found that the total level of fatty acids was similar in the three groups, but the percentage represented by fish-based omega-3 fatty acids was two-fold higher in Japanese men living in Japan (9.2 percent) when compared to white men (3.9 percent) and Japanese-American men (4.8 percent) living in the US.

The research will appear in the Aug 5 issue of the Journal of the American College of Cardiology.