Microbiota-Gut-Brain Axis: Modulator of Host Metabolism and Appetite

Abstract

The gut harbors an enormous diversity of microbes that are essential for the maintenance of homeostasis in health and disease. A growing body of evidence supports the role of this microbiota in influencing host appetite and food intake. Individual species within the gut microbiota are under selective pressure arising from nutrients available and other bacterial species present. Each bacterial species within the gut aims to increase its own fitness, habitat, and survival via specific fermentation of dietary nutrients and secretion of metabolites, many of which can influence host appetite and eating behavior by directly affecting nutrient sensing and appetite and satiety-regulating systems. These include microbiota-produced neuroactives and short-chain fatty acids. In addition, the gut microbiota is able to manipulate intestinal barrier function, interact with bile acid metabolism, modulate the immune system, and influence host antigen production, thus indirectly affecting eating behavior. A growing body of evidence indicates that there is a crucial role for the microbiota in regulating different aspects of eating-related behavior, as well as behavioral comorbidities of eating and metabolic disorders. The importance of intestinal microbiota composition has now been shown in obesity, anorexia nervosa, and forms of severe acute malnutrition. Understanding the mechanisms in which the gut microbiota can influence host appetite and metabolism will provide a better understanding of conditions wherein appetite is dysregulated, such as obesity and other metabolic or eating disorders, leading to novel biotherapeutic strategies.

Short‐chain fatty acids: microbial metabolites that alleviate stress‐induced brain–gut axis alterations

“…; van de Wouw et al . ). As such, our data demonstrated a novel interaction between chronic stress, host metabolism and SCFAs, even though more research into the mechanisms involved is warranted in order to understand the exact role of chronic stress in SCFA–host metabolism interactions.…”

“…Such findings indicate that gut microbial‐derived SCFAs could provide target neural circuits underpinning hedonic food intake, in addition to being implicated in the regulation of homeostatic food intake (van de Wouw et al . ).…”

Intestinal microbiota of broilers submitted to feeding restriction and its relationship to hepatic metabolism and fat mass: Fast‐growing strain

“…Micro‐organisms from these groups can be involved in digestive physiology regulation, by producing beneficial biological compounds (Hemarajata & Versalovic, ) and through the maintenance of intestinal barrier integrity, indispensable for nutrient absorption. For example, Clostridium cluster IV counts include butyrate‐producer strains like Faecalibacterium prausnitzii (Rinttilä & Apajalahti, ), which is an energy source for colonocytes, and also affect host metabolism, especially through insulin and leptin pathways (van de Wouw et al, ). The lack of correlation between performance and Clostridium cluster XIV in our study is in discordance with previous reports (Chambers et al, ; Rubio et al, ).…”

“…Recent studies have linked gut microbiota alterations and hepatic energy metabolism in humans and rodents. This relationship seems to occur in a multi‐factorial way (van de Wouw, Schellekens, Dinan, & Crya, ), and can include effects of microbiota‐produced short‐chain fatty acids (SCFA), therapeutic molecules and bile salt hydrolases (Chambers et al, ). However, there is limited data in literature on this topic in broilers.…”

Effect of tartary buckwheat, rutin, and quercetin on lipid metabolism in rats during high dietary fat intake

“…The contents of signaling molecules such as ghrelin, leptin, and glucagon peptide (glp-1) have shown excess or insufficiency on the body's energy (van de Wouw et al, 2017). Intestinal flora in the host plays an important role in energy metabolism and balance through adjusting the molecular signals released.…”