Hippocampal atrophy and altered brain responses to pleasant tastes among obese compared with healthy weight children

Abstract

Objective The hippocampus is a key structure implicated in food motivation and intake. Research has shown that the hippocampus is vulnerable to the consumption of a western diet (i.e., high saturated fat and simple carbohydates). Studies of patients with obesity (OB), compared to healthy weight (HW), show changes in hippocampal volume and response to food cues. Moreover, evidence suggests that OB children, relative to HW, have greater hippocampal response to taste. However, no study has examined the association of hippocampal volume with taste functioning in children. We hypothesized that OB children, relative to HW, would show a significant reduction in hippocampal volume and that decreased volume would be significantly associated with greater activation to taste. Finally, we explored whether hippocampal activation would be associated with measures on eating and eating habits. Subjects Twenty-five 8–12 year old children (i.e., 13 HW, 12 OB) completed a Magnetic Resonance Imaging scan while participating in a taste paradigm (i.e., 1mL of 10% sucrose or ionic water delivered pseudorandomly every 20 seconds). Results Children with OB, relative to HW, showed reduced left hippocampal volume (t=1.994, p=0.03, 95%CI=−40.23,755.42), and greater response to taste in three clusters within the left hippocampus (z=3.3, p=0.001, 95%CI=−0.241, −0.041; z=3.3, p=0.001, 95%CI=−0.2711, −0.0469; z=2.7, p=0.007, 95%CI= −0.6032, −0.0268). Activation within the hippocampus was associated with eating in the absence of hunger (EAH%; t = 2.408, p=0.025, 95%CI= 1.751708, 23.94109) and two subscales on a measure of eating behaviors (Food responsiveness, t = 2.572, p=0.017, 95%CI= 0.9565195, 9.043440; Food enjoyment, t = 2.298, p= 0.032, 95%CI= 0.2256749, 4.531298). Conclusion As hypothesized, OB children, relative to HW, had significantly reduced hippocampal volume, and greater hippocampal activation to taste. Moreover, hippocampal activation was associated with measures of eating. These results contribute to research on the relationship between obesity, overeating and cognitive impairment.

Sex differences in the association between prenatal exposure to maternal obesity and hippocampal volume in children

“…The linear regression models were unadjusted models (Model 1), and models adjusting for ICV (Model 2), ICV and child age (Model 3), and with additional adjustments for SES and exposure to maternal GDM (Model 4), and additionally, child BMI z ‐score (Model 5). These covariates were previously shown to influence hippocampal volume and thus were added to the model to control for potential confounding (Bauer et al, ; Hair, Hanson, Wolfe, & Pollak, ; Jabès, Thomas, Langworthy, Georgieff, & Nelson, ; Krogsrud et al, ; Mestre et al, ; Uematsu et al, ). Since the majority (93%) of children were prepubertal (Tanner stage < 2), Tanner stage was not adjusted in the regression models.…”

A Preliminary Investigation of the Effects of a Western Diet on Hippocampal Volume in Children

“…Studies in animals have also found similar results, including impaired neurogenesis (10,11) and increased neurodegeneration (9) in the hippocampus following WD consumption. Previous work with children has found a relationship between obesity and left hippocampal volume (31,32). However, these studies did not investigate diet specifically.…”

“…Although this relationship was seen in both hemispheres, it was stronger for the left hippocampus. Furthermore, similar reductions in left hippocampal volume have been found in obese children compared to healthy weight peers [ages 6-8 and 8-12, respectively, (31,32)]. However, as multiple factors can contribute to obesity, the specific impact of diet on hippocampal volume in early development remains unknown.…”

“…No other outliers were detected. In light of previous work demonstrating an association between socioeconomic status (SES) and hippocampal volume (45) as well as BMI and hippocampal volume (31,32), we first used correlation analyses to assess the presence of a relationship between SES, operationalized as annual family income, and weight percentile with left and right hippocampal volumes, respectively. Primary study hypotheses regarding associations between diet variables and hippocampal volume were then tested using multiple regression analyses, covarying for total intracranial volume.…”

“…Using a diet questionnaire completed by children's parents and hippocampal volumes obtained from anatomical MRI scans, we investigated the relationship between WD consumption and hippocampal size. Based on prior studies, we hypothesized that higher fat and sugar consumption would be correlated with decreased hippocampal volume, particularly in the left hemisphere (29)(30)(31)(32). We further examined the individual contributions of sugar and fat consumption to hippocampal volume differences.…”