If you are thinking about eating a
polar bear before it eats you, my advice is
don't, even if you do have a nice bottle of
Chianti ready and waiting to go with it!
Polar bear liver (and also seal liver) contains very high levels of Vitamin A in the form of retinol - up to 30,000 IU/gram which is over 45 times the levels found in cow's liver. Because Vitamin A is one of the few vitamins that is stored by the human liver the level gained from eating even small quantities of polar bear liver can cause toxicity. Within hours of eating polar bear liver (a portion contains several million units of Vitamin A) Arctic explorers developed some of the symptoms of Vitamin A poisoning, including drowsiness, irritability, headache and vomiting, with subsequent peeling of the skin and hair loss.
Due to pollutants entering the food chain polar bear liver also contains heavy metals such as mercury and cadmium, and persistant organochlorine insectides (POPs) - the levels increasing with the age of the bear. These chemicals are known carcinogens and also cause congenital birth defects and blood disorders.