Omega-3 fatty acids have been touted as a way to reduce the risk of a host of cardiovascular problems, but now Greek researchers report that may not be true.
Their finding runs counter to the recommendations of many experts, including American Heart Association officials, who say it's important to consume enough omega-3 fatty acids for good heart health.
"Currently, American Heart Association Guidelines provide a recommendation that fish oil supplementation may be considered in individuals with cardiovascular disease," said Dr Gregg Fonarow, a spokesman for the American Heart Association and a professor of cardiology at the University of California, Los Angeles. He was not involved in the new study.
How the study was done
Omega-3 polyunsaturated fatty acids (fish oil) supplements have been demonstrated in many, but not all, randomized clinical trials to reduce the risk of cardiovascular events by 10% to 15%, Fonarow said.
The Greek team published its report in the Journal of the American Medical Association.
To look at the connection between omega-3 fatty acids and cardiovascular disease, a team led by Dr Evangelos Rizos, of the University Hospital of Ioannina, pooled the results of 20 studies.
This process, called a meta-analysis, attempts to identify common findings across several studies. The limitation of this type of research, however, is in how well the study findings correlate, since they include different populations and different methods.
In this case, the studies included almost 69 000 people who were either taking supplements or not.
What the study found
In all, there were more than 7 000 deaths, almost 4 000 cardiac deaths, more than 1 100 sudden deaths, almost 2 000 heart attacks and almost 1 500 strokes.
Rizos' group didn't find any statistically significant association between supplements and deaths from any cause, cardiac death, sudden death, heart attack or stroke.
"In conclusion, omega-3 polyunsaturated fatty acids are not statistically significantly associated with major cardiovascular outcomes across various patient populations. Our findings do not justify the use of omega-3 as a structured intervention in everyday clinical practise or guidelines supporting dietary administration," they concluded.
The study, however, did show a 9% reduction in cardiac death with omega-3 fatty acid supplementation, Fonarow noted.
"Other outcomes, such as heart attack and sudden death, showed favourable trends, with 11% and 13% reduction in risk," Fonarow said. "As fish oil supplements are widely available, inexpensive, and very well-tolerated, even a small benefit would be valuable at the individual, population and global health level."
While further studies are needed, it remains reasonable to consider dietary consumption of fish or fish oil supplements for modest cardiovascular protection, Fonarow said.
Duffy MacKay, vice president for Scientific and Regulatory Affairs at the Council for Responsible Nutrition in Washington, D.C., added that "it's important to put this in context."
"This has no implications and doesn't change the importance of insuring adequate intake of omega-3 fatty acids through diet or supplements," he said.
MacKay noted that omega-3 fatty acids are not drugs, but nonetheless important for overall health. "We need to moderate our expectations; nutrients are not drugs, so the impact is much more moderate," he said.
Why fish oil is good for the heart
For more on fish oil, visit the U.S. National Library of Medicine.
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