According to the research, a lifetime of eating tuna, sardines, salmon and other fish appears to protect Japanese men against clogged arteries, despite other cardiovascular risk factors.
The study, which is slated for the Aug. 5 issue of the Journal of the American College of Cardiology, suggests that the protection comes from omega-3 fatty acids found in abundance in oily fish.
he research found that the study also found that third- and fourth-generation Japanese Americans had similar or even higher levels of atherosclerosis, or hardening of the arteries - a major risk factor for heart disease, compared to white Americans.
The study was conducted at two universities and one research institute in the U.S. and Japan to compare serum levels of omega-3 fatty acids and atherosclerosis among Japanese, white American and Japanese American men. Based on data from 868 men between the ages of 40 and 49, Japanese men had the lowest levels of atherosclerosis and two times higher levels of omega-3 fatty acids than white Americans or Japanese Americans.
The differences in the levels of atherosclerosis between Japanese and white Americans remained after adjusting for other risk factors - serum cholesterol, blood pressure, cigarette smoking, body mass index and diabetes.
"Our study suggests that very high levels of omega-3 fatty acids have strong properties that may help prevent the buildup of cholesterol in the arteries," said Akira Sekikawa, M.D., Ph.D., study lead author and assistant professor of epidemiology at the University of Pittsburgh Graduate School of Public Health.
Omega-3 fatty acids are a type of polyunsaturated fat found primarily in fish. The two most potent omega-3 fatty acids are known as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and are usually found in oily fishes, such as mackerel, salmon and tuna.