A thought-provoking new study, led by researchers from the University of Cambridge, has uncovered distinct differences in brain structure in obese children compared to those of normal weight. While the direction of the relationship is unknown, the study suggests solid links between brain structure, body mass index, and cognitive functioning.
Obesity, in both children and adults, has been linked in many prior studies with impaired executive function, a collection of cognitive processes managed by the frontal lobe that relate to behaviors such as decision making, self-control and regulation of emotions. To better understand this association, the new Cambridge study examined data from 2700 children aged between nine and eleven.
“This unique and openly available dataset has allowed us to examine the relationships between brain structure, cognitive functions and body weight,” says Paul Fletcher, a Cambridge researcher working on the new study. “The links that we observed suggest that there are very real structural brain and cognitive differences in children who are obese.”
The study uncovered notable associations between increased body mass index and reductions in the thickness of the cortex. Obesity was also linked to a thinning in the pre-frontal region of the cortex. Other data from the cohort confirmed an association between obesity and lowered executive function.
What all this means is relatively unclear, and the researchers are quite reasonably reticent to hypothesize about any kind of causal mechanism that may be at play.
“We saw very clear differences in brain structure between children who were obese and children who were a healthy weight,” says Lisa Ronan, first author on the study. “It’s important to stress that the data does not show changes over time, so we cannot say whether being obese has changed the structure of these children’s brain or whether innate differences in their brains lead them to become obese.”
This fundamental chicken-or-the-egg conundrum will require a great deal of future work to unpack. The study is clear in pointing out there is solid evidence to suggest obesity can have a direct impact on brain function, with bariatric surgery patients, for example, displaying improvements in cognitive abilities following the procedure.
A key plank in future research will be to conduct longitudinal studies identifying whether changes in body mass index over time can result in measurable alterations to brain structure. Working out exactly what is behind this distinct association could offer profound insights into better ways to maintain general health in children and prevent a number of negative health outcomes linked to obesity in later life.
The new study was published in the journal Cerebral Cortex.
Source: University of Cambridge