While fatty fish, such as salmon, is one of the best sources of omega-3 fatty acids, there has been some concern in the past about the health risks associated with high levels of mercury, a known neurotoxin, in some fish.
To investigate, researchers studied more than 900 Swedish men and women who answered questionnaires about the amount of fish in their diet.
The researchers also analyzed the study participant's red blood cells for levels of mercury and selenium, another element that has been tied to heart health.
Researchers found that mercury levels in the subjects were generally low by Scandinavian standards, but higher than much of the U.S. population.
People whose red blood cells showed elevated amounts of mercury did not have a higher risk of cardiac problems than those whose red cells had less of the toxin.
In other words, researchers say the protective nutrients in fish override any harmful effect of mercury at low levels of mercury exposure.
Researchers say their study does not discard the need for restrictions on consumption of high mercury fish, but instead say the findings warrant further investigation.
Currently Health Canada recommends that predatory fish with higher mercury levels such as shark, swordfish, fresh and frozen tuna, escolar, marlin and orange roughy be consumed only occasionally. They also warn that certain groups including young children and women who are or may become pregnant limit their consumption of canned albacore (white) tuna. For more information on Health Canada's guidelines on mercury intake, click here.
Currently, the Heart and Stroke Foundation of Canada advises people to eat fish, especially fatty fish, at least twice per week.
The study was published in the American Journal of Clinical Nutrition.
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