Bearly Metabolizing

Keywords: Polar Bear, Polar Bear Paradox,
Vitamin A

The Story: "One ounce of polar bear liver contains enough Vitamin A (retinol) to kill a person!" I originally wanted to do this post because I've so often read of the toxic amount of Vitamin A stored in a polar bear's liver, occasionally tagged with "scientists do not know why..." What a mystery! Well not quite. Turns out, that's where Vitamin A is stored in the mammalian system, and they just have more. For folks who raise puppies, it is well known that vitamin A supplements help encourage healthy puppy fur, good breast milk and so forth. Well, a bear sure has a lot of fur! What is strange, however, is what is known as the Polar Bear Paradox, that is, why can bears endure feeding behaviors that would cause illness in humans? "Excessive consumption of dietary fat, obesity, and prolonged fasting are well known risk factors for diseases such as coronary heart disease, type II diabetes mellitus and anorexia nervosa." Yet, for the polar bear, points of "metabolic derangement" have made it possible for them to consume humongous amounts of dietary fat, gain tons of weight each year, and then fast for months on end - and remain healthy. Insulin resistance on-demand, unique glycogen storage and dispensary patterns, and lack of ketone-dependent metabolism are a few of the metabolic traits being studied. For me, it's back to the Tabata squats.

Additional Reading:
http://home.earthlink.net/~douglaspage/id89.html

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