Obesity, fitness, and brain integrity in adolescence

Abstract

Objective We set out to ascertain the relationship between insulin resistance, fitness, and brain structure and function in adolescents. Design and Methods We studied 79 obese and 51 non-obese participants who were recruited from the community, all without type 2 diabetes mellitus. All participants received medical, endocrine, neuropsychological, and MRI evaluations as well as a 6-minute walk test that was used to estimate fitness (maximal oxygen consumption). Results Obese adolescents had significantly thinner orbitofrontal cortices and performed significantly worse on Visual Working Memory tasks and the Digit Vigilance task. Insulin sensitivity and maximal oxygen consumption (VO2 max) were both highly correlated with central obesity and orbitofrontal cortical thickness, although insulin sensitivity was the stronger predictor for orbitofrontal cortical thickness. We also found that VO2 max was the only significant physiological variable related to visual working memory. Conclusions This is the first study to report positive associations between insulin resistance, VO2 max, and frontal lobe brain integrity in adolescents. Given the importance of brain health for learning and school performance, we conclude that schools should also emphasize physical fitness in order to maintain structural and functional brain integrity and facilitate academic achievement.

Executive functions in adolescents with binge‐eating disorder and obesity

“…Furthermore, consistent with results from an adult sample, adolescents with BED and obesity and normal‐weight controls attained comparable levels of cognitive flexibility (Kelly, Bulik, & Mazzeo, ). Moreover, no group differences between adolescents with obesity and normal‐weight controls emerged, which is in line with some previous studies in population‐based samples (Gunstad et al, ; Ross et al, ), but contrasts with the findings of lower cognitive flexibility of adolescents with obesity in other studies with population‐based and clinical samples (Maayan et al, ; Verdejo‐Garcia et al, ). Eventually, executive differences between BED, OB, and NW groups might become more apparent in complex everyday situations, which require self‐regulation (Shamosh & Gray, ) and in which binge‐eating episodes are likely to occur (e.g., Elliott et al, ).…”

“…Regarding sustained attention, the BED group did not show difficulties compared to the NW group, indicating healthy levels of sustained attention in adolescents with BED and obesity, which corresponds to first evidence from adults with BED compared to a NW group (Kelly et al ). Confirming previous research in adolescents with obesity (Cserjesi et al, ; Ross et al, ; Verdejo‐Garcia et al, ), the OB group, in contrast, attained lower outcomes in sustained attention than the NW group. However, these differences vanished after controlling for level of education.…”

“…Most importantly, the differences in inhibition between youth with BED and obesity and the NW group remained significant after controlling for education, while differences between the OB and NW groups disappeared after taking into account nonsignificantly lower levels of education in the OB group. This sheds light on the discrepant results on EF in adolescents with obesity (Gunstad et al, ; Maayan et al, ; Nederkoorn et al, ; Ross et al, ) and suggests findings of increased inhibitory difficulties in adolescents with obesity might be due to unascertained eating disorder psychopathology and level of education, which underlines the importance of assessing eating disorders and sociodemographic variables in samples with obesity.…”

Altered Brain Response to Drinking Glucose and Fructose in Obese Adolescents

“…4). This posit is supported by a positron emission tomography–fluorodeoxyglucose study in adults demonstrating that higher BMI is associated with lower baseline prefrontal glucose metabolism (43) as well as previous reports of thinner OFCs (part of the PFC) and diminished performance on various cognitive tasks (visual working memory tasks and digital vigilance tasks) in obese adolescents (44). In keeping with these observations, it has been reported that obese adolescents (mean age 17 years) have higher ratings of disinhibition on the Three Factor Eating Questionnaire, lower performance on the cognitive tests (Stroop color-word score), and lower OFC volume (assessed by MRI) and that disinhibition correlated with BMI, Stroop color-word score, and OFC volume (45).…”

Greater body mass index is associated with reduced frontal cortical volumes among adolescents with bipolar disorder

“…17 In youth, BMI is most consistently associated with reduced grey matter volume in the frontal lobe (FL), specifically in the prefrontal cortex (PFC) and orbitofrontal cortex (OFC). [17][18][19][20][21][22] There is also evidence of reduced volume of medial temporal lobe (MTL) structures, such as the hippocampus and parahippocampal gyrus in overweight and obese adolescents. 23 The FL regions are of particular relevance to BD because they are associated with higher-level cognitive processes, such as executive functioning, decisionmaking and inhibitory control, and are also known to modulate emotion processing.…”