New evidence released today shows that omega-3 supplements have little or no effect on our risk of heart disease, stroke, or death.
Omega 3 is a type of fat. Small amounts of omega-3 fats are essential for good health and are found in the foods we eat. The main types of omega-3 fatty acids are: alpha linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA is usually found in fats from plant foods such as nuts and seeds (walnuts and canola are rich in sources). EPA and DHA, collectively known as long-chain omega-3 fats, are found naturally in fatty fish such as salmon and fish oils including cod liver oil.
The increased consumption of omega-3 fats is widespread around the world as it is widely believed to protect against heart disease. There is more than one possible mechanism by which they can help prevent heart disease, including lowering blood pressure or lowering cholesterol. Omega-3 fats are readily available as over-the-counter dietary supplements and are widely purchased and used.
A new systematic review by Cochrane, published today in the Cochrane Library, combines the results of seventy-nine randomized trials involving 112,059 people. These studies looked at the effects of consuming extra omega-3 fat compared to normal or lower omega-3 on fat and circulatory diseases. 25 studies were rated as very trustworthy because they were well designed and conducted.
The studies recruited men and women, some healthy and others with existing diseases, from North America, Europe, Australia, and Asia. Participants were randomly selected to increase their omega-3 fats or maintain their usual fat intake for at least a year. Most studies looked at the effects of a long-chain omega-3 supplement in capsule form and compared it to a dummy pill. Few rated whole fish intake. Most ALA studies added omega-3 fats to foods like margarine and gave those fortified foods or naturally ALA-rich foods like walnuts to those in the intervention groups and common (non fortified) foods to other participants.
The Cochrane researchers found that increasing long-chain omega-3 fat had little or no benefit in most of the results they studied. They found indications with a high degree of certainty that long-chain omega-3 fats had little or no significant influence on the risk of death for whatever reason. The risk of death for any reason was 8.8% in those who consumed more omega-3 fats compared with 9% in those in the control groups.
They also found that consuming more long-chain omega-3 fats (including EPA and DHA), primarily through dietary supplements, likely had little or no effect on the risk of cardiovascular events, coronary death, events of coronary artery disease, stroke, or heart irregularities . Long chain omega-3 fats likely have reduced some blood lipids, triglycerides, and HDL cholesterol. Reducing triglycerides likely protects heart disease, but reducing HDL has the opposite effect. The researchers gathered information about damage from the studies, but information about bleeding and blood clots was very limited.
The systematic review suggests that consuming more ALA from foods or supplements is likely to have little or no effect on cardiovascular death or death from any cause. However, if you eat more ALA, the risk of heart irregularities is likely to decrease from 3.3% to 2.6%. The review team found that the reduction in cardiovascular events with ALA was so small that about 1,000 people would have to increase their use of ALA for either of them to benefit. Similar results were found for cardiovascular death. They didn’t find enough data from the studies to measure the risk of bleeding or blood clots from using ALA.
Increasing long-chain omega 3 or ALA is unlikely to have any effect on body weight or fatness.
Cochrane’s lead author, Dr. Lee Hooper of the University of East Anglia, UK, said: “We can rely on the results of this review, which contradict the popular belief that long chain omega-3 supplements protect the heart. This large systematic review has information from many thousand people over long periods of time. Despite all this information, we do not see any protective effects.
“The review provides good evidence that taking long-chain omega-3 supplements (fish oil, EPA, or DHA) does not improve heart health or reduce the risk of stroke or death for any reason. The most trusted studies consistently showed little or no Effects of Long-Chain Omega-3 Fats on Cardiovascular Health Although oily fish is a healthy food, the small number of trials has not shown whether eating oily fish protects our hearts.
“This systematic review found moderate evidence that ALA, found in vegetable oils (such as canola or canola oil) and nuts (especially walnuts), provides mild protection for some cardiovascular diseases. However, the effect is very small. 143 people would need to increase their ALA intake to prevent a person from developing arrhythmias. One thousand people would need to increase their ALA intake to prevent a person from dying of coronary artery disease or suffering from a cardiovascular event. ALA is an essential fatty acid Being an important part of a balanced diet and increasing your intake can easily be beneficial for the prevention or treatment of cardiovascular disease. “