Fish-oil capsules. (bigstockphoto)

THE QUESTION Might fish oil supplements, which are thought to help prevent cardiovascular disease, also provide a benefit to those with heart problems?

THIS STUDY analyzed data from 14 studies, involving 20,485 adults (average age: 63) who had had a heart attack, congestive heart failure, coronary heart disease or another form of cardiovascular disease. They had been randomly assigned to take a fish oil supplement or a placebo daily for up to about five years. Virtually no difference was found between those who did and did not take fish oil in the rate of heart attacks, transient ischemic attacks (sometimes called mini-strokes), strokes or sudden cardiac death or in the occurrence of congestive heart failure or angina.

WHO MAY BE AFFECTED? Adults with cardiovascular disease, the leading cause of death in the United States. About 12 percent of Americans have some type of heart disease. Among the lifestyle changes recommended to better protect the heart is eating fatty fish, such as salmon, herring and tuna, at least twice a week. These fish are high in omega-3 fatty acids, which are believed to reduce inflammation that can damage blood vessels and the heart. People sometimes take the equivalent amount of omega-3s as fish oil supplements instead, but it is unclear whether supplements yield the same benefits because of differences in the way the body absorbs them.

CAVEATS Supplement dosages in the 14 studies varied from 0.4 to 4.8 grams a day, and the length of the studies varied. The findings have no bearing on people who do not have cardiovascular disease.

FIND THIS STUDY April 9 online issue of Archives of Internal Medicine.

LEARN MORE ABOUT fish oil at Learn about cardiovascular disease at

Linda Searing

The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.