If you want to protect your heart, stick to exercise and a healthy diet, and pass on the fish oil pills, says a new study.
For years, doctors and health experts have recommended taking fish oil supplements, rich in omega-3 fatty acids, to lower the risk of heart disease. But the latest study on the issue — an analysis of previous clinical trials on the effects of omega-3s — shows that the supplements don’t lower users’ risks of heart attack, stroke, sudden death or death from heart disease or any cause. Although the rates of these events were lower among those taking omega-3 supplements compared with those not taking them, the differences were not statistically meaningful, the authors said.
It’s not the first time that the cardiovascular benefits of fish oil have been questioned: another recent analysis of previous research found that the supplements didn’t prevent heart attack or stroke in people with heart disease. (Separately, other research has suggested that that pills have little effect on boosting memory in Alzheimer’s patients, reducing symptoms of the disease or improving thinking and verbal skills compared with placebo.)
In the current analysis, published in the Journal of the American Medical Association and led by Dr. Moses Elisaf of the Lipid Disorders Clinic at the University Hospital of Ioannina in Greece, the scientists reviewed 20 studies dating back to 1989 that involved 68,680 participants. Volunteers in the studies, most of whom were heart patients, were randomly assigned to take either 1.5 g of omega-3 supplementation or a placebo every day for about two years. They were followed for heart events, including death, heart attack and stroke.
While the omega-3 users showed a 9% lower rate of heart-related death compared with the controls, and an 11% lower rate of heart attack, these differences were too small to attribute to the omega-3 pills.
The findings may lead to some confusion among people — both heart patients and those who are healthy but trying to avoid heart disease — who may be taking omega-3 supplements daily. While some early studies did show a significant benefit from taking fish oil pills, data from newer clinical trials weakened that effect. That may be because at least one early, important study did not blind participants or researchers, meaning that everyone knew who was taking omega-3s or placebo. Further, inconsistencies between the included trials, such as the dosages of supplement used or preexisting conditions among participants, may have contributed to the discouraging findings.
Much other past data showing benefits of omega-3s also came from studies that did not randomize participants into fish oil and placebo groups, and instead retrospectively compared heart events in people who chose to consume more omega-3 fats than others.
Another reason the current study failed to find a benefit may be that more people are using better treatments for heart disease these days, including cholesterol-lowering statin drugs. Elisaf says he wasn’t able to eliminate the potential influence of these medications in lowering rates of heart attack and death from heart disease overall. “We need more data in order to have a clear answer about the role of omega-3 fatty acid supplementation in everyday clinical practice,” he says.
The authors acknowledge that additional research may help determine whether omega-3 supplements may still benefit people depending on their individual risk of heart disease, or if their diets are low in foods that are naturally rich in the fatty acids.
Currently the American Heart Association (AHA) advises people with high triglyceride levels to eat more fatty fish — the omega-3s in oily fish help boost good cholesterol and lower triglycerides — but to discuss supplementation with their doctor if they can’t get enough from their diet. The organization does not recommend the pills in general as a way to protect the heart.
Both the AHA and many doctors recommend eating more fish, however: everyone, including healthy people and heart patients, should eat at least two servings of fish per week to benefit from the omega-3 fats. “If people are taking supplements because their physician prescribed them, they should consult with their physician before stopping,” says Dr. Donna Arnett, president of the AHA and professor of epidemiology at the University of Alabama at Birmingham. “But I would tell them they should not stop eating fish. The results of this study are about dietary supplements. So dietary sources of omega-3s may be different than supplements. They should not assume that dietary sources are not useful.”
Which means that the advice you’ve been hearing all along remains the same — eat more fish. It’s good for your heart.