DEATHS from coronary heart disease among Japanese men is less than half that of Americans.

Whether this is due to genetic, dietary or other factors is being actively debated. There may be new information that might settle the debate.

It was the first international study of its kind. It got published in the Aug 5 issue of Journal of the American College of Cardiology.

The work was the brainchild of the University of Pittsburgh Graduate School of Public Health assistant professor of epidemiology Akira Sekikawa, MD, PhD, and colleagues.

They evaluated data from 868 men aged between 40 and 49 who enrolled in the ERA JUMP (Electron-Beam Tomography, Risk Factor Assessment among Japanese and American men in the Post-World War II Birth Cohort) Study.
About 281 of the current study's subjects were from Japan; 306 were Caucasian men from Pennsylvania; and 281 were Japanese-American men living in Hawaii.

Blood tests measured total fatty acids and the omega-3 fatty acids eicosapentaenoic, docosahexaenoic and docosapentaenoic acids which are commonly obtained by consuming fish.

Ultrasound examination assessed carotid artery intima-medial thickness (IMT), which is used to evaluate atherosclerosis (which links to hardening of the arteries).

Coronary artery calcification (CAC) in the heart's arteries, which also identifies heart disease, was assessed via electron-beam CT scanner.

Dr Sekikawa's team found that although total fatty acid levels were similar among all subjects, the percentage of fish-based omega-3 fatty acids was twice as high among Japanese men compared with Americans of both European and Japanese descent.

Japanese men had significantly less atherosclerosis, as indicated by lower average intima-media thickness and coronary artery calcification.

Among Japanese men, intima-media thickness values declined with rising omega-3 fatty acid levels, a phenomenon that was not observed in either American group.

"The death rate from coronary heart disease in Japan has always been puzzlingly low," Dr Sekikawa wrote.

Their 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.

The study clearly shows that whites and Japanese-Americans have similar levels of atherosclerosis. However, these are much higher than in the Japanese in Japan.

Thus the much lower death rates from coronary heart disease in the Japanese in Japan is very unlikely due to genetic factors.

"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," Dr Sekikawa stated.

Increasing fish intake to two times a week for healthy people is currently recommended in the US. This study shows much higher intake of fish observed in the Japanese (approximately 85.05 gm daily) may have strong effect of reducing hardening of the arteries.

This study comes almost on the back of another major breakthrough on fish and fish oil. In the July, 2008 American Journal of Clinical Nutrition,

Harvard researchers report their finding of a lower nonfatal heart attack risk associated with increased blood plasma levels of the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA), an intermediary between EPA and docosahexaenoic acid (DHA).

The researchers used data from 32,826 women who participated in the Nurses' Health Study between 1989 and 1990. Information obtained from dietary questionnaires was used to calculate omega-3 fatty acid intake.

Blood samples were analysed for omega-3 fatty acids EPA, DHA, DPA, and ALA in plasma and red blood cells.

Over six years of follow-up, nonfatal heart attack was diagnosed in 146 subjects. These were each matched for age and other factors with two control subjects.

Women with higher plasma levels of EPA were found to have a 77 per cent lower heart attack risk.

Subjects with higher plasma concentrations of EPA, DHA, and DPA tended to have increased high density lipoprotein (HDL) or "good" cholesterol and lower triglyceride levels -- both powerful markers of the development of heart disease.

Although a protective effect against fatal coronary heart disease and sudden cardiac death had been associated with omega-3 fatty acids in prior research, their effect in nonfatal heart attack has not been established.

"This prospective study provides new evidence that plasma concentrations of EPA and DPA are associated with a lower incidence of nonfatal myocardial infract (heart attack) among US women," the authors concluded.

So eating fish is good. "Eat lots of it whenever you can" should be the recommendation. Sadly this is not so in today's world.

The authors of the University of Pittsburgh wrote somewhat morbidly that: "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 US could have a very substantial impact on heart disease."

Both studies dealt with fish oil. Not fish. If that is the case, it would be prudent to recommend fish oil supplements given the concerns of the ever increasing build up of the ocean's toxins that end up in fish.

This is even more so that we have technology to purify fish oil. This is not easy as the toxins need to be removed while preserving the highly sensitive omega-3 fatty acids.

In fact advanced technology allows concentration of the omega-3 fatty acids that allows more of it to be packed in a capsule.

In fact there is new technology like molecular distillation and even more superior processes like omatech distillation where newer generation fish oils even come with money back guarantee of purity.

Datuk Dr Rajen M. is a pharmacist with a doctorate in holistic medicine. Email him at health@po.jaring.my