Omega-3 supplements have limited benefits for heart health, study finds

Researchers performed an extensive review of previous studies on omega-3 supplements to find out if they have benefits for heart health.

Omega-3 fatty acids are an essential part of a healthy diet. Some types (long-chain fatty acids – LCn3) are found in oily fish like salmon and mackerel, whilst others (alpha-linolenic acid – ALA) are found in plant-derived foods such as walnuts, flaxseed or canola oil.

Early research suggested that diets rich in omega-3 fatty acids have particular benefits for the heart and cardiovascular system. Advice to increase omega-3 rich foods in daily diets or to take omega-3 supplements was widely promoted as a way to improve heart health. However, later studies have had inconsistent findings. Researchers from The Cochrane Heart Group performed an extensive review of previous studies to examine the effects of increased omega-3 intake on heart health.

The researchers reviewed 79 studies involving over 112,000 people. These studies compared the effects of increased intake of either LnC3 or ALAomega 3 versus continuing a normal diet on cardiovascular diseases such as heart attack and stroke. Twenty-five of the studies were considered well-designed, producing high-quality, trustworthy evidence. Most of the studies looked at the effects of taking omega-3 supplements, but in some studies, omega-3 (in particular ALA) was increased by dietary changes. Participants were adults, mostly from high-income countries, some healthy and some with previous cardiovascular disease. The studies were between 12-72 months duration.

The researchers performed combined analyses of data from the studies. Data on LnC3 and ALA was assessed separately. They looked at the effects of increased omega-3 consumption on death from all causes, cardiovascular causes or heart-related causes. They also examined the rates of cardiovascular diseases such as heart attack, stroke or irregular heart rhythm.

The combined analysis of LnC3 data found that increasing intake had little or no effect on death from all causes, cardiovascular disease death or heart-related death. There was also no effect seen on cardiovascular events such as heart attack, stroke or heart rhythm problems.

The analysis of ALA data found that increasing intake makes little difference to all-cause and cardiovascular deaths, but may slightly reduce heart-related deaths. There was no reduction in coronary heart disease events, but a slight reduction in other cardiovascular disease events and heart irregularities.

This extensive review found that taking LnC3 omega-3 supplements does not have particular benefits for heart or cardiovascular health. Increasing consumption of plant-derived omega 3 fatty acids such as ALA may have some protective heart health benefits. The researchers concluded that there is no need to encourage taking omega-3 supplements for heart health and people would be better advised to eat well and keep fit.

Written by Julie McShane, Medical Writer

References:

1. Abdelhamid AS, Brown TJ, Brainard JS et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease (Review). Cochrane Database of Systematic Reviews 2018, Issue 7, Art. No: CD003177. DOI:10.1002/14651858.CD003177.pub3.
2. Yasgur BS, Omega-3 fatty acids disappoint in cardiovascular protection. Medscape https://www.medscape.com/viewarticle/899619?src=wnl_tp10n_180809_mscpedit&uac=142730PG&impID=1706915&faf=1

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