For the millions who hoped that popping one of those amber omega-3 fish oil pills every day might protect against heart disease, a major study has disappointing news.
The analysis of nearly 70,000 heart patients in 20 studies dating back to 1989 finds that omega-3 doesn't lower users' risks of heart attack, stroke or death from heart disease.
The study is the latest in a long-running controversy over whether omega-3 fatty acids, found in oily fish like salmon, mackerel, trout and tuna, have an impact on heart health.
A decade ago we were told that because people who ate diets heavy in fish had less heart disease, taking fish oil in a pill would obviously provide the same benefit.
Unfortunately, it's not quite that simple. Earlier this year, Korean researchers found that omega-3 supplements had no effect on heart disease or death, based on 20,000 participants in previous trials.
The current research, published in The Journal of the American Medical Association, was led by Moses Elisaf, M.D., of the University Hospital of Ioannina in Greece.
Elisaf and his team looked at 18 trials in which participants were randomly assigned to take either an omega-3 pill or a placebo every day for about two years. The researchers also looked at two trials in which heart patients were told to increase the amount of fish in their diet.
All participants were followed for problems related to heart disease, including heart attack, stroke and death.
Although the rates of heart disease were lower among those taking omega-3 pills compared with those not taking them, the researchers said the differences were too small to be statistically meaningful, Time.com reported.
The Greek researchers also said their findings about omega-3 applied whether the fish oil was from a pill or from eating fish, but that seems to be an overstatement. The results from the two studies about increasing fish in the diet were unclear, a fact they noted in the study.
Bottom line: "You can't think about individual nutrients in isolation," Alice Lichtenstein, director of the Cardiovascular Nutrition Laboratory at Tufts University in Boston, told Reuters.