MedWire News: Japanese people have significantly lower levels of heart disease than their western counterparts, which may be explained by their high intake of fish, say researchers.

"Our study suggests that very high levels of omega-3 fatty acids have strong properties that may help prevent the build-up of cholesterol in the arteries," said lead researcher Dr Akira Sekikawa, from the University of Pittsburgh in Pennsylvania, USA.

Dr Sekikawa and team studied 281 Japanese men, 306 White US men and 281 Japanese-American men aged between 40 and 49 years.

All the participants underwent tests for artery disease, called atherosclerosis, in which levels of fatty deposits in blood vessels and artery wall thickness were measured. They also provided blood samples that were assessed for levels of omega-3 fatty acids.

Analysis revealed that the Japanese men had significantly lower levels of atherosclerosis than men in the other two groups, indicating a reduced risk of heart disease.

Furthermore, omega-3 fatty acid levels were twice as high in Japanese men as in White US men and Japanese-American men.

The difference in atherosclerosis levels between Japanese men and the other participants remained after accounting for risk factors such as blood pressure, cigarette smoking, body mass index and diabetes.

Dr Sekikawa commented: "Increasing fish intake to two times a week for healthy people is currently recommended in the USA. Our study shows much higher intake of fish observed in the Japanese may have strong anti-atherogenic effect."

He added: "The Japanese eat a very high level of fish compared to other developed countries.

"While we don't recommend Americans change their diets to eat fish at these quantities because of concerns about mercury levels in some fish, increasing intake of omega-3 fatty acids in the USA could have a very substantial impact on heart disease.

The research is published in the Journal of the American College of Cardiology.