New research published in the Journal of Science has revealed that the secret to curing obesity could be in the genes of the lands largest carnivore, the polar bear. The diet of our arctic friend consists of blubbery seals, high fat beluga whales, walruses and narwhals yet they are incredibly fit, active and enjoy a lifespan of up to 25 years.
Polar bears need an average of 2kg of fat per day to obtain enough energy to survive and they can digest 84% of the protein and 97% of the fat they eat. Their diet means half their body weight consists of fat and their cholesterol levels are off the chart, yet they are untroubled by heart conditions.
Dr Eline Lorenzen of the University of California, Berkeley, goes on: “Nursing cubs rely on milk that can be up to 30 per cent fat and adults eat primarily blubber of marine mammal prey. Polar bears have large fat deposits under their skin and, because they essentially live in a polar desert and are unable to have access to fresh water for most of the year, they rely on metabolic water, which is a by-product of the breakdown of fat.”
Scientists believe that a mutated gene polar bears have, which is involved in fatty acid metabolism and cardiovascular function is the secret to avoiding obesity. The genes appear to be crucial in their adaptation to extreme conditions and may explain how they avoid clogged arteries. Lead researcher Professor Rasmus Nielsen, from the University of California at Berkeley, U.S., believes this finding could play a pivotal role in helping to overcome obesity in humans.
He said: “The promise of comparative genomics is that we learn how other organisms deal with conditions that we also are exposed to. For example, polar bears have adapted genetically to a high-fat diet that many people now impose on themselves. If we learn a bit about the genes that allow them to deal with that, perhaps that will give us tools to modulate human physiology down the line.”
The research involved analysing the genetic codes of 79 polar bears from Greenland and 10 brown bears from around the world, as they studied the varying bears’ DNA. The results indicate that key genes enable the species to metabolise fats in the bloodstream and liver to prevent heart conditions and the buildup of fatty deposits in the arteries and around the heart.
In mammals the gene APOB encodes the main protein in low-density lipoprotein. Mutation of this gene reflect the critical nature of fat in the polar bear diet and the animal’s need to deal with high blood levels of glucose and triglycerides, in particular cholesterol.
The study also showed that the polar bear is a much younger species than was previously thought. Polar bears diverged from brown bears less than 500,000 years ago, compared with previous estimates of up to five million years. Venturing off on their own evolutionary path they were forced to rapidly adapt to Arctic life. White fur, broad paws for swimming, a distinctive head shape and alterations to their metabolism and heart functions.
What other animals would you like to see greater scientific research into and in relation to what health topic?