Contrary to popular belief that consumption of omega-3 supplements is a simple way to protect the heart, Cochrane researchers in a meta-analysis of trials in over 100,000 people have found little proof that it prevented heart disease. Omega 3 fish oil supplements are taken by millions of people worldwide in a bid to improve their brain and heart health. However, contrary to the belief of their benefits against heart disease, a new Cochrane systematic review published in the Cochrane Library has found that omega 3 supplements are of little or no use at all for the prevention of stroke, heart attacks or deaths.
Omega-3 is a family of fats that include:
- ALA (alpha-linolenic acid) – which the body can’t make for itself but is found in vegetable oils, nuts and seeds
- EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) – which the body can make from ALA but are also present in oily fish and fish oils, including cod liver oil
In addition to some brands of bread, milk, yogurt and spreads extra omega-3 usually AHA) is added. The international study involved the analysis of seventy-nine randomized trials comprising of about 112,059 subjects.
Lee Hooper from the University of East Anglia, UK, and colleagues conducted the study to assess the effects of additional omega 3 fat consumption, compared to lower or usual omega 3, on heart disease and circulation.
The consumption of omega 3 fats is promoted globally due to the belief that it provides protection against heart disease by lowering cholesterol or lowering blood pressure. They are readily available as over-the-counter supplements and are widely used and bought.
Twenty-five studies out of 79 were assessed as highly trustworthy for the review because they were well designed and conducted.
The studies recruited women and men from Asia, Australia, Europe and North America. Some of them were healthy and others had some existing illnesses. The participants were assigned to increase their intake of omega 3 fats or to maintain their usual intake of fat for at least a year.
Most studies investigated the impact of giving a long-chain omega 3 supplements in a capsule form and compared it to a dummy pill. Only a few assessed whole fish intake. Most ALA trials added omega 3 fats to foods such as margarine and gave these enriched foods, or naturally ALA-rich foods such as walnuts, to people in the intervention groups, and usual (non-enriched) foods to other participants.
- Increasing long-chain omega 3 provides little if any benefit on most outcomes that were looked at.
- The researchers found high certainty evidence that long-chain omega 3 fats had little or no meaningful effect on the risk of death from any cause.
- 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.
- Taking more long-chain omega 3 fats (including EPA and DHA), primarily through supplements probably makes little or no difference to the risk of cardiovascular events, coronary heart deaths, coronary heart disease events, stroke or heart irregularities.
- Long-chain omega 3 fats probably did reduce some blood fats, triglycerides, and HDL cholesterol.
- Reducing triglycerides is likely to be protective of heart diseases, but reducing HDL has the opposite effect.
- Increasing long-chain omega 3 or ALA probably does not affect body weight or fatness.
- Eating more ALA through food or supplements probably has little or no effect on cardiovascular deaths or deaths from any cause. However, eating more ALA probably reduces the risk of heart irregularities from 3.3 to 2.6%.
- Reductions in cardiovascular events with ALA were so small that about 1000 people would need to increase consumption of ALA for one of them to benefit.
“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, said Dr. Hooper.
“The review provides good evidence that taking long-chain omega 3 (fish oil, EPA or DHA) supplements do 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 an 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. ALA is an essential fatty acid, an important part of a balanced diet, and increasing intakes may be slightly beneficial for prevention or treatment of cardiovascular disease.”
For more reference log on to http://dx.doi.org/10.1002/14651858.CD003177