You probably know that doctors keep nudging people toward fatty fish like salmon and sardines.
Most of us eat them because they taste good, not because we think about our blood.
A pooled analysis of 29 long-term studies and 183,291 people was published in December 2023 in the journal Stroke. It found that people with the highest omega-3 levels in their blood had a 17% lower risk of stroke overall.
The analysis was led by researchers at Saint Luke's Mid America Heart Institute and the University of Missouri-Kansas City. Participants came from 15 countries.
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The median follow-up was 14 years, and during that time 10,561 participants had a stroke.
EPA appears to carry most of the benefit
Omega-3 is a family of fatty acids, not a single substance. The two most studied are EPA and DHA, both found in oily fish. The new analysis split them apart.
People in the top fifth for EPA had an 18% lower risk of ischemic stroke, the common type caused by a blocked blood vessel. For DHA, the top fifth had a 14% lower ischemic stroke risk.
A third omega-3 called DPA was not linked to stroke risk in this analysis.
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Bleeding stroke
The reason this study carries weight is not only the 17% figure. It is also the question it closes.
Doctors have long worried that omega-3, which thins the blood a little, might raise the risk of hemorrhagic stroke. A hemorrhagic stroke is when a vessel in the brain bursts and bleeds, rather than getting blocked.
In this analysis, higher omega-3 levels showed no link to hemorrhagic stroke at all. Not higher, not lower.
Study author William Harris told the industry outlet NutraIngredients that raising omega-3 into a healthy range does not appear to lift the risk of clinically significant bleeding.
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What this means on your plate
Omega-3 in the blood mainly comes from what you eat. The richest everyday sources are oily fish such as salmon, mackerel, sardines, herring and trout.
The American Heart Association recommends at least two servings of fish a week, ideally fatty fish, as part of a heart-healthy diet. A serving is about 3 ounces of cooked fish, roughly the size of a deck of cards.
For people who rarely eat fish, supplements are another route. The evidence on fish oil pills, however, is more mixed than the evidence on fish itself, as we covered in our earlier look at whether fish oil supplements actually work.
The current study was observational. It cannot prove omega-3 itself caused the lower stroke rate. People who eat more fish may also eat better overall, exercise more, or smoke less.
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But blood levels were measured directly rather than self-reported, and the sheer size of the sample makes the association harder to dismiss.
Anyone already on blood-thinning medication should talk to their doctor before starting a fish oil supplement.
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This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.