What if the structure of your brain was causing problems with your physical health or vice versa? This is the question that researchers from Leiden University Medical Center in the Netherlands set out to answer in their study that harnessed sophisticated MRI technology to assess the link between the brain and the body.
To investigate the correlation, the researchers analysed brain images taken of over than 12,000 participants in the UK Biobank Study, a major trial begun in 2006 to learn more about the genetic and environmental factors that influence disease. The brain scans were taken with state-of-the-art medical resonance imaging machines which revealed both the neuron-rich grey matter of the brain as well as the white matter.
Published in the journal ‘Radiology’, the study revealed that higher levels of body fat were associated with differences in the brain’s structure.
“MRI has shown to be an irreplaceable tool for understanding the link between neuroanatomical differences of the brain and behaviour,” said study lead author Ilona A. Dekkers, M.D.
“We found that having higher levels of fat distributed over the body is associated with smaller volumes of important structures of the brain, including grey matter structures that are located in the centre of the brain,” Dr.Dekkers said.
“Interestingly, we observed that these associations are different for men and women, suggesting that gender is an important modifier of the link between fat percentage and the size of specific brain structures.”
According to the findings of the analysis on the male participants, a higher total body fat percentage was linked with the volume of grey matter overall and in specific structures involved in the reward circuitry and the movement system.
For the female participants, total body fat only showed a negative association with the globus pallidus, a subcortical structure in the brain that communicates with widespread cortical areas to support various functions, including motivation, cognition, and action. For both men and women, a higher percentage of total body fat increased the chances of the brain’s white matter experiencing microscopic changes.
While the implications are not yet clear and further studies needed to conclude indefinitely on the matter, a smaller volume of grey matter insinuates a loss of neurons, which suggests a worrisome correlation between increased body fat and negative changes in the brain. Many neurodegenerative diseases – including amyotrophic lateral sclerosis, Parkinson’s disease, Alzheimer’s disease, and Huntington’s disease occur as a result of the progressive loss of structure or function of neurons.
Changes – even those that are microscopic – to the white matter could have an adverse effect on the brain’s ability to transmit signals effectively. What’s more, since the smaller subcortical grey matter volumes are present in the food-reward circuitry, such changes could result in difficulty controlling weight levels for people who suffer from obesity.
However, since the study did not distinguish between various different types of fat in the body, the researchers emphasised that more analysis must be conducted before a true relationship between body fat and brain shrinkage is established.
“For future research, it would be of great interest to establish whether differences in body fat distribution are related to differences in brain morphological structure, as visceral fat is a known risk factor for metabolic disease and is linked to systemic low-grade inflammation,” said the study’s senior author, Hildo Lamb, MD, PhD, director of the Cardio Vascular Imaging Group of Leiden University Medical Center.
