A new study looked at levels of omega-3 fats, such as those found in fish, and the buildup of plaque in the arteries of 868 middle-age Japanese men living in Japan, Japanese men living in the U.S. and white men living in the United States.
The research, published online in the Journal of the American College of Cardiology, found that omega-3 fat levels in blood of the Japanese men living in Japan were twice as high as the levels in both the Japanese men living in the U.S. and the white men living in the United States.
More importantly, the higher levels of omega-3 fats were directly linked to lower levels of plaque in the arteries, especially when measured by ultrasound imaging of the carotid artery, a noninvasive test considered to be a good surrogate measure of heart disease.
Japan has one of the highest rates of fish consumption in the world, about 3oz per person each day, compared with about two such servings a week in the United States.
Even more striking is the intake of omega-3 fats, which are found in fatty ocean fish such as salmon, sardines and tuna. In Japan, the average intake of omega-3 fat is 1.3g a day, compared with 0.2g stateside.
At the same time, the death rate from heart disease in Japan remains low, about half the rate in the U.S., despite cholesterol levels similar to white men in the U.S. and even higher rates of smoking.
The big question: Is the lower rate of heart disease in Japan due to genetics, high consumption of fish or something else?
"It's very puzzling why the Japanese men have very low heart disease rates," said Akira Sekikawa, lead author of the study and an assistant professor of epidemiology at the University of Pittsburgh.
Milwaukee-area cardiologist William Davis said the study makes a strong case for the ability of omega-3 fats to prevent heart disease.
"It is very persuasive," said Davis, who was not part of the study. "It's another solid piece of evidence."
Over the last several years, Davis has recommended fish oil capsules for about 2,000 people, nearly all of his patients.
"Everybody gets fish oil," he said.
Davis said he recommends that all of his patients take at least 1,000mg a day of either of the two main omega-3 fats, EPA or DHA. For those who have heart disease, he recommends 1,800mg.
Most inexpensive brands available in stores are all that is needed, he said.
Another important question raised by the study is how do omega-3 fats improve heart health?
Other research suggests that omega-3 fats can help prevent irregular heartbeats that can be fatal. In addition, fish oil might help prevent platelets in the blood from sticking together, said Anthony DeFranco, a cardiologist who practices at Aurora St. Luke's Medical Center.
However, the new study suggests, although it does not prove, there is a third potential mechanism: that omega-3 fats might help prevent plaque from building up inside arteries, he said.
"Until we are all in heaven, we will never get absolute (proof), but this is as close to a smoking gun as anyone has gotten," said DeFranco, who was not part of the study. "This study is really revolutionary."
DeFranco noted that people living in Japan might have spent their entire lives eating diets that include a lot of fish. What is unknown is whether a person's heart disease risk would be substantially reduced if the person began taking fish oil capsules at age 40 or 50.
Since World War II, a massive experiment has been going on in Japan: Diet and lifestyle have become more westernized, yet so far, coronary heart disease rates in Japan are about half those in the U.S, according to an editorial accompanying the study.
The lower heart disease rate might be due to the "Japanese factor," which the new study strongly suggests is omega-3 fats, writes William Harris, senior scientist and director of the Metabolism and Nutrition Research Center in Sioux Falls, S.D.
From the August 4, 2008, Prepared Foods e-Flash
