A study conducted by researchers at Duke University clarifies some aspects regarding the question of the greater accumulation of fat in humans compared to other species of primates. In fact, in some ways, it is a mystery: why are humans so subject to obesity compared to many other species of apes and in general primates with which they share 99% of DNA?
Suffice it to say that most other primates have less than 9% body fat while for humans a fat level of between 14 and 31% can be considered healthy and normal. It is not just about eating styles and diets: there must be something genetic behind it. And in fact, the researchers have discovered that the greater aptitude to fat of the humans is connected to a molecular change in the modalities with which the DNA is packed inside the fat cells, a change that would have happened in some point of our past evolution.
This change has reduced our body’s ability to transform white fat, called “bad” fat, into brown fat, which is then dubbed the “good” fat. The study, published in Genome Biology and Evolution, describes the results achieved by Devi Swain-Lenz and Greg Wray, two Duke biologists during experiments on fat samples taken from humans, chimpanzees and Rhesus macaques. By analyzing the genome of the samples, they identified a recurrent DNA fragment that underlies the conversion of fat from one cell type to another.
This fragment would still be fully operational in monkeys while in humans it would have remained “hidden” making us lose the ability to maximize the process that sees the fat cells being diverted to “good” fat. “We are stuck along the path of white fat,” reports Swain-Lenz.
The research could be useful to understand the possibilities of activation or deactivation of some genes to reactivate the process and therefore counteract obesity, but the same researchers report that at the research level we are still very far from such a goal: “I don’t think it’s as simple as pushing a switch: if it was, we would have understood it a long time ago,” reports Swain-Lenz.