Stroke: 17% lower risk with omega-3 supplements

A new study confirms the link between consuming foods rich in omega-3 and a lower risk of stroke. People who eat at least 5 servings of fish per week have a 13% lower risk of stroke. Focusing specifically on ischemic strokes, the risk reduction reaches 17%. To reach these conclusions, researchers from the University of North Carolina at Chapel Hill (USA) analyzed data from 16 studies involving a total of 402,127 individuals. The results were published in the European Journal of Clinical Nutrition.

Unfounded doubts

Previous studies have already found a strong association between consuming fish rich in Omega-3 and specifically between intake of these fatty acids and reduced stroke risk. An analysis published in Stroke by researchers at the Karolinska Institute in Stockholm (Sweden) showed that eating fish rich in Omega-3 about 3 times a week reduces stroke risk by 6%. In a later study, the same researchers found that high Omega-3 intake is associated with a 16% reduction in stroke risk. Such compelling data seemed to leave no room for doubts about the protective role of these fatty acids. However, a recent publication in JAMA, which was heavily criticized, suggested omega-3s are not helpful in protecting the cardiovascular system. This new study further strengthens the hypothesis that eating fish rich in these nutrients reduces stroke risk.

Why omega-3 protect against ischemic stroke

Unlike other research, the analysis from Chapel Hill distinguishes between stroke types. There are two main types of stroke: hemorrhagic, caused by bleeding in the brain tissue, and ischemic, caused by interruption of blood flow due to clots in the brain vessels. Scientists explain that the protective effect of Omega-3 against stroke is based on their ability to inhibit platelet aggregation, thus reducing the chance of clot formation that causes ischemic events. Conversely, this anti-platelet effect might suggest increased risk of hemorrhagic strokes, but this study dispels that doubt: researchers observed no increase in hemorrhagic stroke incidence among those consuming large amounts of fish.

Long-term benefits

The authors also emphasized the duration of Omega-3 intake. Some studies that did not find an association between Omega-3 consumption and stroke risk only evaluated short-term supplementation. In contrast, the studies included in this analysis averaged 12.8 years of follow-up. The researchers conclude that short-term clinical trials in patients cannot exclude long-term effects on stroke risk in the general population, as confirmed by this analysis.

Source Xun P, Qin B, Song Y, Nakamura Y, Kurth T, Yaemsiri S, Djousse L, He K, “Fish consumption and risk of stroke and its subtypes: accumulative evidence from a meta-analysis of prospective cohort studies”, Eur J Clin Nutr. 2012 Oct 3. doi: 10.1038/ejcn.2012.133