NEW YORK (Reuters Life!) The benefits for heart health of eating fish may outweigh concerns over the potential negative impact of increased exposure to mercury as a result, according to a study.

But restrictions are still needed in connection with fish high in mercury, which include species such as perch, shark, swordfish and halibut, said a Swedish team whose results were published in the American Journal of Clinical Nutrition.

Maria Wennberg, a public health researcher at Umea University in Sweden, and her colleagues studied more than 900 Swedish men and women who answered questionnaires about the amount of fish in their diet. The team also analysed the subjects' red blood cells for levels of mercury and selenium.

The American Hearth Association recommends that people consume at least two servings of fish a week.