Risk of Stroke Lowered For Women Who Eat Fish

Summary
A recent study on Swedish women looked at a possible link between consumption of fish and the occurrence of stroke. The relevant information on diet was gathered through questionnaires handed out to female subjects of stroke. Data corresponding to over ten years of follow-up was included and analyzed in this study. The incidence of total stroke was found to be inversely correlated with higher quantities of fish consumption, especially lean fish. However, there is no clarity on strokes associated with the brain or hemorrhages.

Introduction
It is well established that fish are a rich source of the long-chain omega-3 polyunsaturated fatty acids (PUFAs) – eicosapentaenoic acid and docosahexaenoic acid. These compounds are known to enhance cardiovascular health. But results of certain studies on the relationship between stroke and consumption of fish were contradictory. Specific flaws were noticed in these studies. It is likely that the type of fish or method of cooking could have nullified any beneficial effects. These and other limitations of prior research were overcome in this current study by looking at overall fish consumption, particular varieties of fish, occurrence of total stroke and subtypes in a large population.

Methodology
•    More than 34,000 women aged between 49 and 83 years were studied in this project.
•    Details regarding lifestyle, family history, smoking and metabolic activity across ten years were collected by means of two questionnaires.
•    The diet pattern, especially regarding type and frequency of fish consumed over the past year, was obtained on a food-frequency questionnaire.
•    Stroke incidence, history and follow-ups for the above women were obtained and all the data were correspondingly analyzed with the help of statistical tools.

Key findings
•    The group of women with the highest fish consumption reported fewer incidences of stroke; they also reported fewer incidences of brain strokes and hemorrhages, but these results were not statistically significant.
•    Intake of lean fish, which include cod, monkfish, haddock, grouper, etc., caused a decreased risk of stroke, including brain strokes.
•    Furthermore, there were 33 percent fewer cases of total strokes in women who had three or more servings of lean fish per week, than in women who did not have any lean fish in their diets.

Shortcomings
The use of self-administered questionnaires was a major drawback in this study, as any wrong information provided would directly influence calculated risk factors.  The evaluation of hypertension based on non-clinical self-reports was also not foolproof. Finally, although most critical risk factors were studied, it is probable that some influencing variable was left unaccounted for.

Conclusion
High protein content and low saturated fat content are just a couple good reasons for adding fish to one’s diet. Fish are a rich source of selenium, which offers protection against strokes due to its antioxidant properties. The amino acid, “taurine,” is also found in fish and has been known to help lower blood pressure and triglyceride levels. Lean fish are specifically known to decrease blood pressure in patients with heart disease. Thus, we understand that there is a definite risk reduction for stroke in women who consume high quantities of fish, particularly lean fish. The researchers state that additional studies in this area could focus on various species of fish and their influence on different subtypes of strokes.

For More Information:
Fish Consumption and Risk of Stroke in Swedish Women
Publication Journal: American Journal of Clinical Nutrition, December 2010
By Susanna C. Larsson; Jarmo Virtamo; Division of Nutritional Epidemiology, National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden, and the Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland

*FYI Living Lab Reports Are Summaries of the Original Research.
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