A new UK review has found that omega 3 supplements have little or no effect on reducing the risk of heart disease, stroke or death.
Led by the University of East Anglia, the new study analyzed the results of 79 randomized trials involving a total of 112,059 people — some healthy and some with existing conditions — who lived across North America, Europe, Australia and Asia.
The studies investigated the effects of consuming additional omega 3 fat compared to usual or lower levels of omega 3 on diseases of the heart and circulation, with participants asked to either increase their omega 3 fats or to maintain their usual intake of fat for at least one year. Many studies compared long-chain omega 3 supplements in a capsule form to a dummy pill, with only a few assessing whole fish intake.
Small amounts of omega 3 fats are essential for good health, with the main types of omega 3 fatty acids including alphalinolenic acid (ALA), normally found in plant foods such as nuts and seeds, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), both of which are collectively called long chain omega 3 fats and are naturally found in fatty fish and fish oils including cod liver oil.
Although increasing our consumption of omega 3 fats is widely promoted in order to protect against heart disease, the researchers found that increasing long-chain omega 3 through either food or supplementation provides little, if any benefit, on most most health outcomes investigated in the study. This includes risk of death from any cause, with the team finding little difference between the two groups — the risk of death from any cause was 8.8% in people who had increased their intake of omega 3 fats, compared with 9% in people in the control groups.
In addition, upping intake of long-chain omega 3 fats (including EPA and DHA) mainly through supplements also made little or no difference to the risk of cardiovascular events, coronary heart deaths, coronary heart disease events, stroke or heart irregularities. However, eating more ALA was found to probably reduce the risk of heart irregularities from 3.3 percent to 2.6 percent.
Long-chain omega 3 fats also appeared to reduce some blood fats and triglycerides — which can help protect against heart disease — although they also lowered levels of HDL cholesterol, known as the “good” cholesterol, which could increase the risk of heart disease.
Commenting on the findings, Cochrane lead author, Dr. Lee Hooper said, “We can be confident in the findings of this review which go against the popular belief that long-chain omega 3 supplements 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.”
“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.”
The results will be published online in the Cochrane Library.