Many of us probably know that eating a very-high-fat diet will not only make us gain weight, but it will also increase our risk of heart disease. But surprisingly, there are 2 disparate population groups that, notably, consume very high quantities of dietary fats, yet have a very low incidence of cardiovascular disease, polar bears and traditional Alaskan Eskimos. How is that possible? Does it have to do with the types of fats they eat, or to specific physiological adaptations? The answer is yes, to both of these questions.
A recent study published in the highly touted scientific journal Cell (Polar Bear Study), showed that polar bears and brown bears diverged in evolutionary history less than 500,000 years ago. This is a surprisingly short time, in evolutionary terms. During this time, polar bears moved north, subsisted on a blubber-rich diet of primarily marine mammals and fish, and became profoundly obese. Interestingly though, these bears do not develop fatty deposits in blood vessels (atherosclerotic plaques) or suffer from cardiovascular diseases (CVDs) that afflict most humans with diets rich in fat. How can that be? The answer to this seemingly paradoxical question was revealed by the gene studies in this publication, and was discussed recently in Science Daily (Researcher Interviews). The researchers found that polar bears had evolved several gene variants that helped them adapt to the high-fat diet. These variants were in genes which related to fatty acid metabolism and cardiovascular function. The researchers concluded that this study may provide insight into how to protect humans from the ill effects of consuming too much dietary fat.
The second group mentioned above, arctic Eskimos called the Intuits, also eat high-fat diets and have traditionally had very low incidence of CVD. This has been referred to as the ‘Intuit Paradox’ (Discover Magazine). The Intuits historically ate a high-fat diet consisting of seal and walrus meat and other blubbery marine mammals. Although we don’t know about specific gene variants in this population relating to heart disease, we do know that the composition of fat they consumed is very different from fat consumed today by most Americans. The Intuit diet was traditionally high in mono- and polyunsaturated fatty acids (and protective omega-3 fatty acids), and low in saturated and trans fats. This seems rather unexpected since most of us know that animal fats are high in saturated fat. It had to do with the source of the fats. It turns out the wild-animal fats are different (less saturated fat; higher in monounsaturated fats, like in olive oil) from farm-animal fats and processed fats (which also contain damaging trans fats). Moreover, cold water fishes and marine animal fats are particularly rich in polyunsaturated fats and omega-3 fatty acids.
So this then leaves us with 3 options if we choose to consume lots of dietary fats and still want to be healthy: 1) hope that we rapidly evolve like the polar bears; 2) consume more fat from wild-caught animals; or 3) focus on fats derived from plant foods like seeds, nuts and whole grains. What will your choice be?