Gut microbiome: Microflora association with obesity and obesity-related comorbidities

Highlights

• Obesity is influenced by genetic as well as dietary and lifestyle pattern.

• Imbalance in the gut microbiota has been found associated with obesity.

• Probiotics and prebiotics modulate gut microbiota, thereby influence occurrence of obesity.

• Fiber-enriched diet and plant based bio-actives helps in the alleviations of obesity associated complications.

Abstract

Obesity and obesity-related comorbidities have transformed into a global epidemic. The number of people suffering from obesity has increased dramatically within the past few decades. This rise in obesity cannot alone be explained by genetic factors; however, diet, environment, lifestyle, and presence of other diseases undoubtedly contribute towards obesity etiology. Nevertheless, evidence suggests that alterations in the gut microbial diversity and composition have a role to play in energy assimilation, storage, and expenditure. In this review, the impact of gut microbiota composition on metabolic functionalities, and potential therapeutics such as gut microbial modulation to manage obesity and its associated comorbidities are highlighted. Optimistically, an understanding of the gut microbiome could facilitate the innovative clinical strategies to restore the normal gut flora and improve lifestyle-related diseases in the future.

Introduction

The potential role of gut microbiota in the development of obesity and obesity-related comorbidities has attracted much attention from the public and academics. Excess energy intake and sedentary lifestyle with reduced physical activity are the most popular factors which could contribute to obesity and its related comorbidities. Its development is a complex process and the contributing factors including environmental factors and genetic susceptibility are often shrouded in mystery [1]. Lately, several scientific reports suggest that the altered diversity of the gut microbiome may play a role in the development of obesity, and other metabolic, and inflammatory disorders [[2], [3], [4], [5], [6], [7], [8], [9], [10]].

The host and gut microbiota concomitantly evolve through symbiotic interactions influenced by genetics, background, age, sex, immune system and gut motility [11,12]. Furthermore, gut microbiota in individuals predisposing to obesity could be altered by changes in the diet, prebiotic and probiotic use (Fig. 1). Some of the key factors that affect maintaining a balanced healthy gut microbiota are; however, not limited to nutritional imbalance, harmful microbial infections, diseases, alteration in intestinal barrier, and gut microenvironment [13,14]. Many research findings indicate that the imbalance in gut microbiota may pose a threat for host metabolism and energy homeostasis that triggers the development of conditions like insulin resistance, diabetes mellitus, and obesity [2,3,7,[15], [16], [17]]. For instance, the microbial imbalance is characterized by altered secretion of blood glucose, lowering metabolic hormones known as incretins, misregulated production of short-chain fatty acids known as butyrate, enhanced proportions of gut microbiota lipopolysaccharide (LPS). Translocation of host microbiota-derived LPS to the bloodstream beyond its threshold results in metabolic endotoxemia, which could activate a Toll-like receptor-mediated inflammatory response, and in severe cases could cause organ damage and cardiovascular disease [18]. As previously indicated, modifications in the gut microbiota have been linked to obesity and its related-comorbidities. This review provides a general overview of the potential role of gut microbiota in the development of adverse metabolic state as well as the respective prevention and treatment strategies.