However, the study, published in the British Medical Journal website, said taking fish oil supplements doesn't seem to have the same effect.
Dr. Rajiv Chowdhury of Cambridge University in England and Oscar H. Franco of Erasmus MC Rotterdam in the Netherlands said regular consumption of fish and long-chain omega-3 fatty acids have been linked with a reduced risk of coronary heart disease.
Current guidelines recommend eating at least two portions of fish a week, preferably oily fish like mackerel, sardines or salmon, but evidence supporting a similar benefit for stroke was unclear.
An international team led by Chowdhury and Franco analyzed the results of 38 studies -- involving nearly 800,000 individuals in 15 countries -- to help clarify the association between fish consumption and risk of stroke or mini-stroke -- transient ischaemic attack -- collectively known as cerebrovascular disease. A total of 34,817 cerebrovascular events were recorded during the studies.
Study participants eating two to four servings a week of the fish had a moderate but significant 6 percent lower risk of cerebrovascular disease compared with those eating one or fewer servings of fish a week, while participants eating five or more servings a week had a 12 percent lower risk.
In contrast, levels of omega-3 fats in the blood and fish oil supplements were not significantly associated with a reduced risk, the study said.