Popping pills of omega-3 polyunsaturated fatty acids, the type found in oily fish like salmon, may not help prevent heart attacks, although previous research suggested that they protect against cardiovascular diseases.
The latest research, based on an analysis of 20 studies involving almost 70,000 patients, found that taking the pills did not lower heart attack or stroke risks, or even death rates from heart problems or any other cause.
The previous theory held that fish oil supplements help make the blood less 'sticky' and lower blood pressure by relaxing vessels, thus making heart attacks and strokes less likely, the "Journal of the American Medical Association" (JAMA) reports.
"Our findings do not justify the use of omega-3 as a structured intervention in everyday clinical practice or guidelines supporting dietary omega-3 polyunsaturated fatty acid administration," said Evangelos Rizos from the University Hospital of Ioannina, Greece, according to the Telegraph.
The relevance of the JAMA study has been called into question by the Health Supplements Information Service, which is funded by manufacturers. Carrie Ruxton, from the service, said: "Omega-3 fatty acids are well known for their heart health benefits, and there is a significant body of evidence to prove that."