Gut Microbiota and Emotional Eating Behavior: Neuropsychological Pathways Involving Stress, Anxiety and Depression

Emotional eating is described as eating without feeling physically hungry to cope with stress, anxiety and negative emotions. Hypothalamic–pituitary–adrenal (HPA) axis activity associated with stress, anxiety and depression, along with changes in cortisol levels and neurobiological processes that regulate appetite and reward mechanisms, can trigger emotional eating behavior. The gut microbiota may influence emotional eating through modulation of hypothalamic–pituitary–adrenal (HPA) axis activity, as hypothesized from a neuropsychological perspective. The aim of this review is to evaluate the neurobiological and neuropsychological mechanisms associated with stress, anxiety and depression that may play a role in the potential relationship between the gut microbiota and emotional eating; to provide a comprehensive perspective on the current evidence regarding these mechanisms; and to investigate potential intervention approaches. The gut microbiota is a dynamic ecosystem that regulates metabolic, immune and neuroendocrine homeostasis through host-microbiota interactions. The gut microbiota may influence the gut–brain axis through the metabolism of short-chain fatty acids, tryptophan and GABA, along with BDNF and FXR/TGR5 signaling pathways, thereby regulating emotional eating behaviors associated with stress, anxiety and depression. As a result, alterations in the gut microbiota can affect emotional eating associated with stress, anxiety and depression through various pathways. Current evidence is largely based on in vitro and animal studies, while human studies are mostly observational, limiting causal inferences regarding the relationships between gut microbiota, depression, anxiety, and stress. Future studies should address the impact of the gut microbiota on emotional eating through individualized intervention studies that evaluate stress, anxiety and depression.