THERE has been a long standing debate. Which impacts heart disease more -- nature (genes) or nurture (lifestyle and environment)?

A new study may have settled it. I wrote about it in the article "Fish Oil Keeps Japanese Men Hale and Hearty" (New Sunday Times, Aug 10).

I am writing about it again to emphasise the main key points which may have been missed and which have big implications.

Death from coronary heart disease among Japanese men is less than half that of Americans. This is a well known fact.

Now is it due to a "better" lifestyle or genes? A new cleverly designed study may have settled this once and for all.
The international study was published in the Aug 5, issue of Journal of the American College of Cardiology.

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

The team evaluated data from 868 men aged 40 to 49 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.


There were three groups in the study:

- 281 were Japanese from Japan.

- 306 were Caucasian men from Pennsylvania.

- 281 were Japanese-American men living in Hawaii.

Thus, we could compare Japanese living in their homeland with those living in the United States who have similar gene pools with their Caucasian counterparts as some kind of a "control".

We are comparing Japanese who live in the US and Japan, This is very important as it would quickly even out that the "Japanese have better genes" argument.

Blood tests measured total fatty acids and the omega-3 fatty acids eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) which are commonly obtained by consuming fish.

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

Coronary artery calcification 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. This was 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. This was not observed in either American groups.

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

This study strongly 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.

One simple conclusion: the much lower death rates from coronary heart disease in the Japanese in Japan is very unlikely due to genetic factors as their American relatives did not enjoy better heart health despite sharing the same gene pools.

"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."

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 85g daily) may have strong effect of reducing hardening of the arteries.

Consuming fish or fish oils can prevent hardening of the arteries. This is a very important piece of information.

"Eat lots of fish whenever you can" should be the clear simple 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".

I was deeply disappointed. The study dealt with fish oil and not fish.

If that is the case, it would be prudent to recommend fish oil supplementation given the concerns of the ever increasing build up of the ocean's toxins that end up in fish.

There is new technology like molecular distillation and even more superior processes like omatech distillation that newer generation fish oils now 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