Stroke: 17% lower risk by taking omega-3 supplements

A new study confirms the link between consumption of omega-3-rich foods and a lower risk of stroke. Those who consume at least 5 servings of fish per week have a 13 percent lower risk of experiencing a stroke. If we then focus on ischemic type strokes, the risk reduction reaches 17%. To reach these conclusions, a group of researchers from the University of North Carolina at Chapel Hill (United States) analyzed data from 16 different studies involving, in total, 402,127 individuals. The results of the analysis were published in the pages of the European Journal of Clinical Nutrition.

Unsubstantiated doubts

Already in the past, several studies have found a close association between consumption of fish rich in Omega-3 and, more specifically, between intake of these fatty acids and reduced risk of stroke. An analysis published in Stroke by researchers at Karolinska Institutet in Stockholm, Sweden, for example, showed that eating fish rich in Omega-3 about 3 times a week reduced the likelihood of having a stroke by 6 percent. In subsequent research, the same scholars found that high intakes of Omega-3 were associated with a 16 percent reduction in stroke risk. Such overwhelming data seemed to leave no further room for doubt about the protective role played by these fatty acids. However, a recent publication in JAMA, which was also the subject of much criticism, had insinuated that omega-3s were not useful in protecting the cardiovascular system. This new study, however, further strengthens the hypothesis that there is an association between consumption of fish rich in these nutrients and reduced risk of stroke.

The reasons for the protective effect against ischemic stroke

Compared with other research, the analysis conducted by the Chapell Hill researchers allows a distinction to be made between different types of stroke. There are, in fact, two different kinds of stroke. While the hemorrhagic one is due, as the name implies, to a hemorrhage in the nerve tissue, theischemic stroke is due to the interruption of blood flow because of the presence of clots in the vessels that flow in the brain. In fact, the scientists explain, the protective action of Omega-3s against stroke is based on their ability to inhibit platelet aggregation and, therefore, reduce the likelihood of the clots underlying ischemic events. Conversely, one would think that this antiplatelet action would increase the risk of hemorrhage and, therefore, hemorrhagic strokes. In fact, this study removes even that doubt. In fact, the researchers observed no increase in the incidence of hemorrhagic strokes in those who consume a lot of fish.

Long-term benefits

The authors of the new analysis also emphasized another aspect: how long Omega-3s are taken. Indeed, some studies that did not find an association between consumption of these nutrients and stroke risk evaluated the effect of taking Omega-3 supplements for a limited period of time. In this case, however, the studies included in the analysis had an average duration of 12.8 years. According to the researchers, short-term clinical trials conducted in patients cannot rule out long-term effects on stroke risk in the general population, which were 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: accumulating evidence from a meta-analysis of prospective cohort studies," Eur J Clin Nutr. 2012 Oct 3. doi: 10.1038/ejcn.2012.133