The hypothalamus, a brain region involved in appetite control, is different in overweight and obese people.
- The hypothalamus, a small region of the brain, is larger in young adults who are overweight and suffer from obesity.
- This increase in volume was most noticeable in the subregions of the hypothalamus that control appetite by releasing hormones to balance hunger and satiety.
- Inflammation of the hypothalamus, caused by a high-fat diet, could promote insulin resistance and obesity.
The hypothalamus, a region located in the heart of the brain, is an important neuroendocrine center for the control of appetite and satiety. “Although we know that the hypothalamus plays an important role in determining how much food we eat, we have very little information about this region of the brain in humans. Indeed, it is very small and difficult to distinguish on traditional MRI scans”, said Stephanie Brown, a researcher at the University of Cambridge (UK), in a statement.
The hypothalamus is larger in overweight and obese young adults
So she decided, with her team, to carry out a study to find out more about the link between the volume of the hypothalamus and obesity. For the purposes of their work, published in the journal NeuroImage Clinicalthe scientists used an algorithm to analyze the brain scans of 1,351 young adults with different BMI scores, looking for differences in the hypothalamus. “We compared underweight adults (including people with anorexia nervosa), healthy volunteers, overweight participants, and obese people in a series of complementary analyses,” they specified.
According to the results, the overall volume of the hypothalamus was significantly greater in overweight and obese patients. “This phenomenon has also been observed for a number of hypothalamic subregions, which control appetite by releasing hormones to balance hunger and satiety. ‘hypothalamus and BMI’, specified the authors.
Inflammation of the hypothalamus caused by a high-fat diet
Scientists have suggested that this association is linked to hypothalamic inflammation “as observed in animals in response to a high-fat diet”. Inflammation of the hypothalamus could promote insulin resistance and obesity. According to the team, other research has shown that this inflammation can raise the satiety threshold of animals, meaning they have to eat more than usual to feel full.
“If what we see in mice holds true in humans, a high-fat diet could trigger inflammation in our appetite control center. Over time, this would alter our ability to tell when we’ve eaten enough. and how our body processes blood sugar, which would cause us to gain weight,” explained Stephanie Brown.
The authors said more work is needed to confirm whether the enlarged hypothalamus is a result of being overweight or whether people with larger hypothalamus are predisposed to eat more. It is also possible that these two factors interact with each other.
