Teen obesity may damage parts of the brain that regulates appetite, emotion

Obesity in adolescence may harm regions of the brain that control appetite, emotion and cognitive function—a finding researchers hope fuels the creation of better means to address a burgeoning epidemic.

Scientists from the University of São Paulo, in Brazil, recently made that discovery by studying MRI scans of 59 overweight teenagers and comparing them with 60 more from healthy individuals. Using a technique called “diffusion tensor imaging,” or DTI, to track the diffusion of water along the brain’s signal-carrying white matter tracts, they noticed damage to key parts of the brain. The results were presented Sunday, Dec. 1, at the RSNA’s 105th Scientific Assembly and Annual Meeting, in Chicago.

"Brain changes found in obese adolescents related to important regions responsible for control of appetite, emotions and cognitive functions," study co-author Pamela Bertolazzi, a biomedical scientist and PhD student, said in a statement.

Recent research has suggested that obesity may trigger inflammation in the nervous system. Wanting to further test those theories, Bertolazzi and colleagues compared DTI for dozens of teens and derived a measured called “fractional anisotropy” to correlate the condition of each subjects’ white matter and indicate increasing damage.

Their MRI analysis pinpointed dipping fractional anisotropy values in a bundle of nerve fibers that connects the left and right hemispheres of the brain, along with another region related to emotional control and reward.  

Bertolazzi and colleagues noted that damage patterns also correlated with brain inflammation markers such as leptin, which is made by fat cells to regulate energy levels and fat stores. Some obese individuals’ brains do not respond to leptin, which can lead to overeating despite having adequate stores of fat.

The team next plans to conduct additional studies to figure out if this inflammation in obese teens’ brains is a consequence of structural changes in the brain.

This latest study was a continuation of another analysis presented at RSNA back in 2017, with the previous iteration focusing on changes in brain white matter in the amygdala, hippocampus, thalamus, cingulate gyrus, fornix, insula, putamen, orbital gyrus and bilateral hypothalamus. Those involved said finding such clues is crucial as the overweight youth population continues to grow.

“Childhood obesity has increased 10 to 40 percent in the last 10 years in most countries,” Bertolazzi said at the time. “If we are able to identify the brain changes associated with obesity, this DTI technique could be used to help prevent obesity and avoid the complications associated with the condition.”