The finding, published in the British Journal of Nutrition, was a surprise to researchers who thought the fatty acids in fish would protect against the risk of blood clots, The Local reported Thursday.

The study of 1,100 people in Sweden's Norrland region found that men who ate large amounts of fish were more prone to strokes, even when taking into account factors such as diabetes, high blood pressure, high cholesterol levels and smoking, the newspaper said.

Researchers say they do not know if there is some pollutant in the fish that increases the risk of stroke or if other lifestyle factors, such as vegetable consumption, exercise and alcohol habits contributed to the risk, the newspaper said.

From the June 18, 2007, Prepared Foods e-Flash