“It has long been known among Eskimos and arctic travelers that the ingestion of polar-bear liver by men and dogs causes severe illness. It has also been reported that the liver of a certain seal (Phoca barbata) is poisonous, although opinion on this point, is less unanimous…
During a recent expedition made by one of us to north-east Greenland, 1939-40, specimens of polar- bear liver were collected with a view to identifying the toxic substance. On chemical and biological examination these specimens were found to be very rich in vitamin A, as also was a specimen of liver from P. barbata. It seems probable that this high concentration of vitamin A is the cause of toxicity, and that the ingestion of more than small amounts of liver leads to hypervitaminosis A.”
K. Rodahl and T. Moore. The vitamin A content and toxicity of bear and seal liver. Biochem J. 1943 Jul; 37(2): 166–168. (full text)
