By ANAHAD O'CONNOR, Reporter
People who put their faith in fish oil supplements may want to reconsider. A new analysis of the evidence casts doubt on the widely touted notion that the pills can prevent heart attacks in people at risk for cardiovascular disease.
Fish oil supplements have become some of the most popular dietary pills on the market, largely on the strength of medical research linking diets high in baked and broiled fish to lower rates of heart disease. Across the United States, annual sales of purified fish oil, commonly sold as omega-3 fatty acids, are in the neighborhood of a billion dollars. And in some parts of Europe, doctors routinely prescribe fish oils to patients with heart disease.
But the new report, a large meta-analysis that pooled and then analyzed data from various clinical trials involving thousands of patients, found that taking omega-3 fatty acids did not reduce the risk of further cardiovascular problems in patients who already had heart disease. The authors sifted through about 1,000 studies to collect their data, carefully selecting only the trials that were the best quality – 14 randomized, placebo-controlled studies involving a total of 20,485 patients with a history of heart disease.
The heart patients in the trials were all treated with purified fish oil supplements for at least a year, and were followed to determine whether omega-3 fatty acids had an effect on their subsequent risk of major cardiovascular problems like heart attacks, strokes, angina and heart failure. The analysis, published in Archives of Internal Medicine, found “insufficient evidence” of a protective effect against future cardiovascular events in the large number of heart patients who were studied.
In an accompanying editorial, experts cautioned that the research is not the final word on fish oils. The authors, Dr. Frank B. Hu and Dr. JoAnn E. Manson, from the Harvard School of Public Health, noted that the trials included in the analysis may not have been carried out over a long enough time to show the true effect of regularly taking fish oil over the long term.
They also pointed out that taking fish oil might still have a sort of insurance or protective effect in people who haven’t already developed heart disease. Other studies that are under way — and were not included in the new report — are following thousands of healthy adults to see whether fish oil supplements can ward off heart attacks and strokes in people who have no previous history of heart disease.
At the moment, there is not a lot of evidence that taking fish oil supplements can protect or strengthen the heart in healthy adults, said the lead author of the new study, Dr. Seung-Kwon Myung, chief of the carcinogenesis branch of the National Cancer Center in South Korea. But in the meantime, he and the authors of the editorial say it may make the most most sense to spend your money on actual fish, rather than fish oil supplements.
They argue that by eating fish, you end up replacing other less healthy protein sources, like processed foods and red meat. For that reason, a diet high in fatty fish — one that includes at least two servings a week — may make a difference over the long term, they say.