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Spotlight on omega-3s for heart health

For many consumers, omega-3 fatty acids have become synonymous with cardiovascular health, but researchers recently have cast doubt on their efficacy. What’s next for omega-3s?

In July 2018, a Cochrane review suggested that increasing omega-3 consumption in the form of EPA and DHA has little or no impact on cardiovascular health. It claimed to be “the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date” and led to a host of negative headlines. Then the European Medicines Agency dealt omega-3 suppliers another blow in December, when it ruled that omega-3 does not help prevent further damage to the heart or blood vessels after a heart attack.

Meanwhile, the market for supplements and foods fortified with omega-3s continues to grow, and major food and nutrition authorities continue to recommend increased omega-3 consumption. The European Food Safety Authority, for example, concluded in 2009 that 250 mg should be the reference intake value for long-chain omega-3 fatty acids, and an analysis published in the British Journal of Nutrition in 2011 also identified 250 mg of EPA and DHA omega-3s as the minimum amount necessary to reduce cardiac risk. According to a 2016 review, about 80% of the world’s population is thought to consume less than 250 mg per day.

Many of the most well-established benefits of omega-3s are cardiovascular-related, such as reducing levels of triglycerides and blood cholesterol – and the Cochrane reviewers acknowledged these effects.

Those in the omega-3 industry have pointed out that the reviewers excluded sponsored trials from their assessment, meaning that many large-scale trials that have found positive associations between heart health and omega-3 consumption were left out. In addition, several other meta-analyses that have reached the opposite conclusion have received far less media attention.

GOED, a non-profit trade organisation that aims to increase global omega-3 intakes to adequate levels, and OmegaQuant founder and omega-3 researcher Bill Harris have been among the most vocal critics. Harris has pointed out that some of the study subjects already were older or had heart conditions before trials began, meaning that if omega-3s are indeed ineffective once the heart muscle is damaged, these studies would naturally lean toward a negative conclusion. In addition, the studies typically only ran for two or three years and many gave only low doses.

As an aside, it is also important to note that there is strong evidence that omega-3 fatty acids are useful in other situations, especially in pregnancy. Another recent Cochrane review linked omega-3 consumption with lower risk of preterm birth, and the nutrient is widely recommended because of strong links to improved foetal eye and brain health.

However, heart health continues to be the most referenced benefit on foods that contain omega-3s. The results of several new trials are set to be published in the next two years, but the problem with proving the benefits of omega-3 remains; their effects on heart health are thought to accumulate over decades, rather than years, presenting a major challenge for researchers.

In the meantime, the nutrient enjoys broad recognition and is so highly regarded that many manufacturers have backed away from making specific claims, preferring simply to highlight the presence of omega-3s and allowing consumers to draw their own conclusions.