Did you know DNA influences your fat sensitivity and diabetes risk?
The disconnect between diet and evolution, and how it predisposes us to type 2 diabetes
Darwin describes evolution as the process by which organisms acquire changes in their DNA so they can adapt to their environment. Evolution is an iterative process with no end point and continual evolution to retain the “fittest” individuals. But what happens if the environment changes too fast, and DNA doesn’t get enough time to adapt?
According to scientists the emergence of chronic diseases (e.g. diabetes and obesity) is a direct outcome of the discordance between the environment and our DNA. Our genomes (the entirety of our DNA) are scrambling to keep up with the dramatic changes of the western diet. In the midst of processed and readily available food sources, metabolic genes that were previously advantageous are quickly turning into disease risk genes. Such is the case for a variant of the FABP2 gene. This genetic change garnered us cold tolerance, but now increases our risk of type 2 diabetes.
The FABP2 gene encodes a fat binding protein that chaperones fats in our gut. Fats have a wide range of functions in our bodies. They are used for energy, aid in the absorption of vitamins, and play a role in blood clotting and inflammation. The activity of the FABP2 protein varies from person to person because of a DNA change found within the FABP2 gene. Around 75% of Caucasians inherit the normal version of FABP2, while the rest have a version of the protein known as FABP2 A54T (aka rs1799883).
The FABP2 A54T version binds and absorbs fats better, and studies show it is more frequent with increasing latitude (i.e. in colder climates). This is not surprising, because being able to extract and store more dietary fats, allows one to stay warm (and alive!) in cold conditions. The idea is that as our ancestors moved out of Africa into cooler climates, the A54T variant was retained, since it proved “fitter” when challenged with cold weather.
But times have changed. We now hold the power to wear shorts indoors on a frigid winter’s day, and no longer rely on food to keep us warm. Not only that, our lifestyle has changed from hunters and gatherers (that consumed all natural food) to today, where we often have easy access to a plentiful food supply. And as we know, this food is often not the healthiest option, with lots of processed foods high in fats and sugars. Even some of the healthier options, like grains, have been processed and refined so they are not as natural as they once were.
In the span of just ~10,000 years (which is quite short in an evolutionary time scale), we’ve managed to expose our DNA to a multitude of previously foreign foods. At the same time, the quantity and quality of this food has also changed drastically. The speed at which these transformations took place, hasn’t given our DNA a fair chance to fight back or evolve.
So, our (western) diet, which is riddled with processed foods, fatty domesticated meats and vegetable oils, has turned the fat storing capabilities of FABP2 into a risk factor for chronic diseases. The FABP2 A54T variant is linked to increased fat and glucose levels in our blood, as well as a higher risk for type 2 diabetes and cardiovascular disease. Interestingly, the link between type 2 diabetes varies between ethnicities, and how exactly this difference pertains to environmental factors (such as the cold) remains to be seen.
Type 2 diabetes is characterized by persistently high sugar levels, and is one of the fastest growing diseases in the world. However, with current knowledge, managing and mitigating the risk of diabetes is as simple as changing diet and physical activity levels. If you carry the FABP2 A54T variant, will you take the steps to improve your diet and avoid diabetes?