Eating Fish Can Decrease Risk for Heart Disease

July 30, 2008 — Near-daily consumption of fish over a lifetime is thought to be the reason that Japanese men are far less likely to have dangerous plaque build-up in their blood vessels than caucasian or Japanese-American men. This difference is seen even in light of high levels of smoking in the Japanese male population.

"Japanese living in Japan eat fish every day, about 100 grams [3.5 ounces] every day," says study author Dr. Akira Sekikawa. "They also have very low rates of coronary heart disease, even with a high rate of smoking and other risk factors."

Dr. Sekikawa is an assistant professor of epidemiology at the Graduate School of Public Health at the University of Pittsburgh in Pennsylvania. Results of the study are published in the Journal of the American College of Cardiology.

Heart and Neck Arteries Affected
Dr. Sekikawa's study included 281 Japanese men, 306 caucasian 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 in 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 (BMI), 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 caucasian 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 caucasian men and the men in Japan.

Fish Consumption Important
"Fish is an important factor in keeping the Japanese healthy," says the author of an accompanying editorial, William Harris, Ph.D., director of the Metabolism and Nutrition Research Center, Sanford Research/USD, in Sioux Falls, SD.

"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 adds.

Dietary Recommendations
Current American Heart Association (AHA) guidelines recommend eating oily fish, such as salmon or albacore tuna, at least twice a week if you do not 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 should not consume more than two grams of fish oil daily without first consulting your doctor, because of a risk of excessive bleeding.

Dr. Harris says it is important to consume fish or fish oil on an ongoing basis. "A month of supplements won't get you there," he says. But, if you do not like fish, he says that fish oil supplements can also improve your health. However, he suggests that you read the supplement label and make sure that each capsule contains one gram of omega-3s. And, he says, they do not have to be expensive to be effective.

If you do not have heart disease, he says, two grams a day "is more than adequate." And, if you like fish, that is 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," Dr. Harris adds.

Always consult your physician for more information.