The risk of suffering a stroke can be affected by food choices.
However, there's an important exception … one that explains the mixed outcomes of some studies looking at links between fish intake and stroke risk… see “Fried Fish Seen to Raise Stroke Risk
Now, two new studies provide heartening affirmation of the power of fish and omega-3s to suppress the risk of stroke.
Women's stroke risk lowered by fish
A population study by researchers from Sweden's famed Karolinska Institute suggests that omega-3s from fish or supplements may help prevent stroke in women (Larsson SC et al. 2012).
Dr. Susan C. Larsson and her colleagues analyzed data collected from 34,670 women aged 49 to 83 years who were free of any cardiovascular disease.
They compared the women's intake of dietary fats and cholesterol to the rate of stroke over an average of 10.4 years.
After adjusting the results for stroke risk factors, their analysis linked higher intake of long-chain omega-3s (EPA and DHA) from fish or fish oil supplements to reduced risk of stroke.
The women with the highest omega-3 intake were 16 percent less likely to suffer a stroke, compared with those with the lowest omega-3 intake.
In contrast, higher intake of cholesterol was linked to higher risk of stroke.
The women with the highest cholesterol intake were 20 percent more likely to suffer any type of stroke and 29 percent to suffer an ischemic stroke … the kind caused by clots released from the plaque in clogged, stiff brain arteries.
No links were seen between stroke risk and intake of total fat, saturated fat, monounsaturated fat, polyunsaturated fat, plant-form omega-3s, or omega-6 fats.
As the researchers wrote, “… intake of long-chain omega-3 PUFAs is inversely associated with risk of stroke, whereas dietary cholesterol is positively associated with risk.” (Larsson SC et al. 2012)
Evidence review affirms anti-stroke power of fish
Scientists from the University of North Carolina at Chapel Hill reviewed 16 diet-health studies, which included 402,127 participants and lasted an average of 12.8 years.
Their analysis linked higher intakes of fish, and the omega-3 fatty acids they contain, to a reduced risk of stroke.
Specifically, they found that consuming five or more portions of fish per week was associated with a 13 percent reduction in the risk of all types of stroke.
Further, the same level of consumption was linked to a 17 percent drop in the risk of ischemic stroke … again, this is the type caused by brain clots released from arterial plaque.
The risk reduction for hemorrhagic stroke was not as large.
But as they wrote, “It makes biological sense that fish intake was found to be inversely related to the risk of ischemic but not hemorrhagic stroke because of the different etiopathogenesis [cause] of these two stroke subtypes.” (Xun P et al. 2012) .
The added a key, reassuring point: “The anti-platelet activity of [long chain omega-3s] that protects against ischemic stroke development may be a risk factor for hemorrhagic stroke development.
However, we did not observe an increased risk of hemorrhagic stroke in higher categories of fish consumption.” (Xun P et al. 2012)
While fish and omega-3s can't eliminate stroke risk, they seem to be smart prevention allies.
He K, Song Y, Daviglus ML, Liu K, Van Horn L, Dyer AR, Goldbourt U, Greenland P. Fish consumption and incidence of stroke: a meta-analysis of cohort studies. Stroke. 2004 Jul;35(7):1538-42. Epub 2004 May 20.
Larsson SC, Orsini N. Fish consumption and the risk of stroke: a dose-response meta-analysis. Stroke. 2011 Dec;42(12):3621-3. Epub 2011 Sep 8.
Larsson SC, Virtamo J, Wolk A. Dietary fats and dietary cholesterol and risk of stroke in women. Atherosclerosis. 2012 Mar;221(1):282-6. Epub 2012 Jan 8.
Larsson SC, Virtamo J, Wolk A. Fish consumption and risk of stroke in Swedish women. Am J Clin Nutr. 2011 Mar;93(3):487-93. Epub 2010 Dec 29.
Myint PK, Welch AA, Bingham SA, Luben RN, Wareham NJ, Day NE, Khaw KT. Habitual fish consumption and risk of incident stroke: the European Prospective Investigation into Cancer (EPIC)-Norfolk prospective population study. Public Health Nutr. 2006 Oct;9(7):882-8.
Larsson SC, Orsini N. Fish Consumption and the Risk of Stroke: A Dose–Response Meta-Analysis. Stroke. 2011;42:3621-3623 published online before print September 8 2011, doi:10.1161/STROKEAHA.111.630319
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. [Epub ahead of print]