Increased consumption of omega-3 fats is widely promoted globally because of a common belief that that it will protect against heart disease.

But a new UEA-led Cochrane review—the international gold standard for high-quality, trusted health information—finds that omega-3 supplements offer little, if any, benefit.

Omega-3 is a type of fat. Small amounts are essential for good health, and they can be found in the food that we eat.

The main types of omega-3 fatty acids are alpha­linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).

ALA is normally found in fats from plant foods, such as nuts and seeds (walnuts and rapeseed are rich sources). EPA and DHA, collectively called long-chain omega-3 fats, are naturally found in fatty fish, such as salmon and fish oils, including cod liver oil.

Omega-3 fats are also readily available as over-the-counter supplements and they are widely bought and used.

The new Cochrane systematic review combines the results of 79 trials involving 112,059 people.

These studies assessed the effects of consuming additional omega-3 fat, compared to usual or lower omega-3, on diseases of the heart and circulation.

The studies recruited men and women, some healthy and others with existing illnesses, from North America, Europe, Australia, and Asia.

Participants were randomly assigned to increase their omega-3 fats or to maintain their usual intake of fat for at least a year.

Lead author Dr. Lee Hooper, from UEA’s Norwich Medical School, said: “The findings of this review go against the popular belief that long-chain omega-3 supplements, including fish oils, protect the heart. This large systematic review included information from many thousands of people over long periods. Despite all this information, we don’t see protective effects.”

“The review provides good evidence that taking long-chain omega-3 (fish oil, EPA, or DHA) supplements does not benefit heart health or reduce our risk of stroke or death from any cause.”

“The most trustworthy studies consistently showed little or no effect of long-chain omega-3 fats on cardiovascular health. On the other hand, while oily fish is a healthy food, it is unclear from the small number of trials whether eating more oily fish is protective of our hearts.”

“This systematic review did find moderate evidence that ALA, found in plant oils such as rapeseed or canola oil, and nuts, particularly walnuts, may be slightly protective of some diseases of the heart and circulation.”

“However, the effect is very small; 143 people would need to increase their ALA intake to prevent one person developing arrhythmia.”

“One thousand people would need to increase their ALA intake to prevent one person dying of coronary heart disease or experiencing a cardiovascular event.”

The study is published in the Cochrane Database of Systematic Reviews on July 18, 2018.