Hypothalamic differences discovered in people who are living with overweight or obesity
A groundbreaking study by researchers at the University of Cambridge has provided new insights into the role of the hypothalamus in controlling appetite. This small yet critical region of the brain, which is about the size of an almond, appears to have structural differences in those who are living with overweight or obesity compared to those of healthy weight.
Dr. Stephanie Brown from the Department of Psychiatry and Lucy Cavendish College, University of Cambridge, noted the importance of the hypothalamus in regulating appetite but also acknowledged the difficulty in studying it in living humans due to its small size.
The study team addressed this challenge by using a machine learning algorithm to analyse MRI scans of 1,351 young adults across different BMI categories. Published in Neuroimage: Clinical, their findings revealed that the hypothalamus’s overall volume was significantly larger in those who with overweight or obesity.
These findings offer further evidence to the connection between brain structure, weight, and food consumption, as obesity is a global concern affecting over 1.9 billion people worldwide. The condition increases risks for numerous health problems, including type 2 diabetes, heart disease, stroke, and mental health issues.
The team also explored the possibility that the changes in the hypothalamus might be related to inflammation. Previous animal studies have shown that a high-fat diet could cause inflammation in the hypothalamus, leading to insulin resistance and obesity. In some cases, just three days of a fat-rich diet was enough to trigger inflammation.
Dr. Brown emphasised that if similar processes occur in humans, a high-fat diet could impact our ability to sense when we’ve eaten enough, leading to weight gain. The researchers hypothesised that the brain might react to inflammation by enlarging specialised immune cells, known as glia, causing the hypothalamus to be larger.
Professor Paul Fletcher, the study’s senior author, expressed hope that this new approach to analysing brain scans would deepen our understanding of appetite control in obesity. While the exact implications of these findings are still unclear, more research is needed to confirm whether the increase in hypothalamic volume is a cause or result of being overweight, or if those with larger hypothalami are naturally inclined to eat more.
Supported by the Bernard Wolfe Health Neuroscience Fund, Wellcome, NIHR Cambridge Biomedical Research Centre, and additional funding from Alzheimer’s Research UK, the study presents a transformative view of obesity. It opens new avenues for exploring obesity from a neurological perspective, potentially revolutionising how obesity and overweight conditions are understood and treated. Future studies may provide essential insights into intervention strategies, reshaping the way we approach this global health challenge.
