Obesity represents one of the most challenging health problems today. This global pandemic has caused a higher incidence of cardiovascular diseases and types 2 diabetes.
But that’s not all, numerous scientific studies have linked obesity with an increased risk of accelerated cognitive decline and dementia, suggesting that the disease causes changes in the brain.
To obtain more information about these changes, a group of scientists led by Ilona A. Dekkers, analyzed the results of brain images of more than 12,000 participants in the Biobank study of the United Kingdom, an important clinical trial started in 2006 to better understand the factors genetic and environmental factors that influence health. For this, among other techniques, magnetic resonance scans were used that provided information on both the gray matter and white matter.
The results, published in Radiology, show some clear associations between the percentage of body fat and the shape and structure of the brain.
The Dekkers team has discovered that higher levels of body fat are associated with differences in brain shape and structure, including smaller volumes of gray matter.
“We discovered that having higher levels of fat distributed in the body – explains Dekkers – is associated with smaller volumes of important structures of the brain, including gray matter structures found in the center of the brain. It is interesting to note that these associations are different in men and in women, suggesting that gender is an important modifier of the link between the percentage of fat and the size of specific brain structures.”
The analysis showed that, in men, a higher percentage of total body fat correlated with a lower volume of gray matter in general and in specific structures involved in reward circuits and the movement system. In women, on the other hand, total body fat only showed a significant negative association with the pale globe (globus pallidus), a structure involved in voluntary movement. In both sexes, a higher percentage of body fat increased the likelihood of changes in the white matter of the brain.
A smaller volume of the gray matter suggests the loss of neurons and changes in the white matter could negatively affect the transmission of signals in neural networks. Since it is also known that gray matter volumes play a role in food reward circuits, these changes are what would make it more difficult for obese people to control their weight.
Obesity, Brain Volume, and White Matter Microstructure at MRI: A Cross-sectional UK Biobank Study