Switching Adolescent High-Fat Diet to Adult Control Diet Restores Neurocognitive Alterations.

Chloé Boitard,Shauna L Parkes,Amandine Cavaroc,Nathalie Castanon,Gustavo Pacheco-Lopez,Sophie Tronel,Guillaume Ferreira,Sophie Layé,Etienne Coutureau,Frédéric Tantot

doi:10.3389/fnbeh.2016.00225

Abstract

In addition to metabolic and cardiovascular disorders, obesity is associated with adverse cognitive and emotional outcomes. Its growing prevalence in adolescents is particularly alarming since this is a period of ongoing maturation for brain structures (including the hippocampus and amygdala) and for the hypothalamic-pituitary-adrenal (HPA) stress axis, which is required for cognitive and emotional processing. We recently demonstrated that adolescent, but not adult, high-fat diet (HF) exposure leads to impaired hippocampal function and enhanced amygdala function through HPA axis alteration (Boitard et al., 2012, 2014, 2015). Here, we assessed whether the effects of adolescent HF consumption on brain function are permanent or reversible. After adolescent exposure to HF, switching to a standard control diet restored levels of hippocampal neurogenesis and normalized enhanced HPA axis reactivity, amygdala activity and avoidance memory. Therefore, while the adolescent period is highly vulnerable to the deleterious effects of diet-induced obesity, adult exposure to a standard diet appears sufficient to reverse alterations of brain function.

Highlights

Overconsumption of energy-dense, palatable foods is a recognized source of weight gain and obesity
Post hoc analyses indicated that the high-fat diet (HF) fed rats were significantly heavier than C fed rats (Fisher’s post hoc: p < 0.001) but no significant difference was found between the two HF fed groups (p = 0.26)
3 months after removal of the HF, rats with a history of adolescent HF consumption showed no deficits in amygdala-dependent memory and marginal improvements in hippocampal-dependent memory

Summary

Introduction

Overconsumption of energy-dense, palatable foods is a recognized source of weight gain and obesity. While the incidence of overweight and obesity is increasing in all age ranges, it is notable in adolescents (Ogden et al, 2012). This is alarming since adolescence is a period of neurobehavioral shaping required for life-long cognitive processing (Spear, 2000). Adolescence is sensitive to environmental challenges, like diet, and there is compelling evidence that an energy-dense diet is more harmful when consumed during adolescence than in adulthood. The overconsumption of sugar or fat throughout adolescence, but not adulthood, is associated with changes in reward-related behaviors in rats including deficits in motivation (Vendruscolo et al, 2010) and attenuated conditioned place preference induced via a palatable food reward (Privitera et al, 2011)

Methods

Results

Conclusion