TUESDAY, July 29, 2008 (HealthDay News) -- Despite high levels of smoking, Japanese men are far less likely to have dangerous plaque build-up in their blood vessels than white or Japanese-American men, a difference that researchers believe stems from a lifelong, near-daily consumption of fish.
"Japanese living in Japan eat fish every day, about 100 grams every day," said study author Dr. Akira Sekikawa, an assistant professor of epidemiology at the Graduate School of Public Health at the University of Pittsburgh in Pennsylvania. "They also have very low rates of coronary heart disease, even with a high rate of smoking and other risk factors."
Results of the study are in the Aug. 5 issue of the Journal of the American College of Cardiology.
Current American Heart Association (AHA) guidelines recommend eating oily fish, such as salmon or albacore tuna, at least twice a week if you don't have heart disease. If you already have heart disease, the AHA suggests getting at least one gram of omega-3 fatty acids daily, preferably from fatty fish. However, the AHA cautions that you shouldn't consume more than two grams of fish oil daily without first consulting your doctor, because of a risk of excessive bleeding.
Sekikawa's study included 281 Japanese men, 306 white American men, and 281 Japanese-American men. Along with giving blood samples, all of the men underwent electron beam computed tomography (EBCT) to measure coronary artery calcification (plaque deposits on the heart's arteries) and ultrasound examinations of the carotid artery in the neck.
Overall, the researchers found that Japanese-American men had the highest number of heart disease risk factors of all three groups. They had the highest average body-mass index, blood pressure, triglycerides and the highest levels of diabetes.
The Japanese men living in Japan had far higher rates of smoking -- 47 percent -- and smoking is one of the most significant heart disease risk factors.
But they had significantly less coronary artery calcifications and less build-up in their carotid arteries.
The levels of omega-3 fatty acids in the blood were 9.2 percent for men living in Japan, 3.9 percent for white men, and 4.8 percent for Japanese-American men. Yet, Japanese-American men had more coronary artery calcifications and more build-up in their carotid arteries than the white men and the men in Japan.
"Fish is an important factor in keeping the Japanese healthy," said the author of an accompanying editorial, William Harris, director of the Metabolism and Nutrition Research Center, Sanford Research/USD, in Sioux Falls, S.D.
"The combination of increased fish oil and a low saturated fat diet is probably the best way to lower heart disease risk. Eskimos have a diet high in omega-3s, but also high in saturated fat, and they don't have the same low levels of heart disease," he added.
Harris said what's important is to consume fish or fish oil on an ongoing basis. "A month of supplements won't get you there," he said. But, if you don't like fish, he said that fish oil supplements can also improve your health, but he suggested that you read the supplement label and make sure that each capsule contains one gram of omega-3s. And, he said, they don't have to be expensive to be effective.
If you don't have heart disease, he said, two grams a day "is more than adequate." And, if you like fish, that's even better.
"Choose oily fish, not fried fish, but fish that naturally contain omega-3s, like salmon, sardines, albacore tuna, herring and mackerel, and you need to eat about two 4-ounce servings a week," Harris added.
More information
To learn more about fish, omega-3s and heart health, visit the American Heart Association.
