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. http://www.ajcn.org/content/early/2010/11/03/ajcn.2010.29408