Japan's Heart-Healthy Diet: Fish Is Key
Study Shows High Omega-3 Levels in Japanese Diet Cuts Heart Disease Rates
High Omega-3 Levels continued...
Other good sources of omega-3 include foods such as flaxseed and canola
oils, soybean, tofu, and walnuts. Omega-3 fatty acids are often sold as
capsules but can upset the stomach and should be taken with food.
Harris is working to develop a soybean-based omega-3-enriched oil through a
grant from the company Monsanto.
He believes that many of the foods we eat will soon be fortified with
omega-3 in the same way that they are now fortified with folic acid and other
"Either we get people in the U.S. to start liking oily fish, which
probably isn't going to happen, or we find another way of getting it into our
food," he says.
Fish Eaters Had Less Plaque
The study by Sekikawa and colleagues included 281 Japanese men living in
Japan, an equal number of Japanese men living in the U.S., and 306 white men
who lived in the U.S.
All the men were in their 40s, and all underwent blood testing to determine
serum levels of fatty acids, including omega-3. The men also had two tests for
atherosclerosis -- one measuring the thickness of the artery wall in a major
neck artery that sends blood to the brain and the other measuring plaque in
arteries leading to the heart.
While total fatty acid levels were similar in the three groups, blood
omega-3 levels in the Japanese men living in Japan were 45% higher and 80%
higher, respectively, than in Japanese men and white men living in the U.S.
And both measures of artherosclerosis showed less plaque buildup in the
arteries of the Japanese men living in Japan. Atherosclerosis levels were
similar in both Japanese-Americans and in white Americans.
The study appears in the Aug. 5 issue of the Journal of theAmerican
College of Cardiology.
"This indicates that much lower death rates from coronary heart disease
in the Japanese in Japan is very unlikely due to genetic factors," Sekikawa
The 'Omega-3 Hypothesis'
In an editorial accompanying the study, Harris writes that what he calls the
"omega-3 hypothesis" grew from research on the Inuit Eskimos of
Greenland conducted almost four decades ago.
Despite eating a diet low in fruits, vegetables, and complex carbohydrates
and high in fat and cholesterol, the Eskimos had very low rates of heart
disease. Researchers concluded that the reason was the incredibly high levels
of omega-3 in their diets from the consumption of large amounts of fish, whale,
But recent studies suggest that heart disease rates among Alaskan Eskimos
are now higher than among whites in the U.S., even though fish consumption in
the population remains high.
"At least part of the problem in Alaska appears to be not a lack of
omega-3 but the introduction of massive amounts of shortenings and other
saturated fats into their Westernizing diet," Harris writes.