Journal of Gastroenterology and Digestive Diseases

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Perspective - Journal of Gastroenterology and Digestive Diseases (2024) Volume 9, Issue 4

Metabolic Pathways: The Interplay between Gut Microbiota and Obesity

Keita Igarashi *

Department of Applied Biological Science, Tokyo University of Agriculture and Technology, Japan

*Corresponding Author:
Keita Igarashi
Department of Applied Biological Science, Tokyo University of Agriculture and Technology, Japan
E-mail: lgarashik@tuat.jp.co

Received: 29-Jun-2024, Manuscript No. JGDD-24-142705; Editor assigned: 29-Jun-2024, PreQC No. JGDD-24-142705 (PQ); Reviewed: 13-Jul-2024, QC No. JGDD-24-142705; Revised: 18-Jul-2024, Manuscript No. JGDD-24-142705(R); Published: 26-Jul-2024, DOI: 10.35841/jgdd-9.4.220

Citation: : Igarashi K. Metabolic Pathways: The Interplay between Gut Microbiota and Obesity. J Gastroenterol Dig Dis.2024;9(4):220

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Introduction

Metabolic pathways, intricate networks of chemical reactions occurring within cells, are crucial for maintaining life and health. These pathways regulate energy production, storage, and utilization, and they are significantly influenced by the gut microbiota, the diverse community of microorganisms residing in the digestive tract. The interplay between gut microbiota and metabolic pathways has profound implications for obesity, a condition characterized by excessive fat accumulation and associated with numerous health risks [1].

Gut microbiota play a pivotal role in modulating host metabolism through various mechanisms. One of the primary ways is through the fermentation of dietary fibers into short-chain fatty acids (SCFAs), such as acetate, propionate, and butyrate. SCFAs serve as an energy source for colonocytes, the cells lining the colon, and have systemic effects on energy metabolism. For instance, butyrate enhances insulin sensitivity and reduces inflammation, while propionate is involved in gluconeogenesis and appetite regulation. These SCFAs also influence the release of gut hormones, such as glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), which play roles in regulating satiety and energy balance [2, 3].

The composition of the gut microbiota significantly affects the production of SCFAs. Individuals with obesity often exhibit an altered gut microbiota composition, with a lower diversity and a higher ratio of Firmicutes to Bacteroidetes. This shift is associated with an increased capacity for energy harvest from the diet, contributing to greater fat storage. Studies have shown that transferring the gut microbiota from obese individuals to germ-free mice can lead to weight gain and fat accumulation in the recipient mice, underscoring the role of gut microbiota in obesity [4].

Another crucial mechanism through which gut microbiota influence host metabolism is the modulation of bile acids. Bile acids, synthesized from cholesterol in the liver and secreted into the intestine, aid in the digestion and absorption of dietary fats. Gut bacteria modify primary bile acids into secondary bile acids, which have various metabolic effects. These modified bile acids can activate receptors such as the farnesoid X receptor (FXR) and the G-protein-coupled bile acid receptor 1 (TGR5), influencing glucose metabolism, lipid metabolism, and energy expenditure. Dysregulation of bile acid metabolism, often seen in obesity, can lead to impaired energy homeostasis and metabolic disorders [5].

Inflammation is another link between gut microbiota and obesity. A high-fat diet, commonly associated with obesity, can disrupt gut barrier function, allowing bacterial components like lipopolysaccharides (LPS) to enter the bloodstream. This condition, known as metabolic endotoxemia, triggers systemic inflammation, which is a key factor in the development of insulin resistance and metabolic syndrome. Certain gut bacteria, such as Akkermansia muciniphila, help maintain gut barrier integrity and reduce inflammation. However, their abundance is often decreased in obese individuals, contributing to increased gut permeability and inflammation [6].

Gut microbiota also influence the host's metabolic pathways through the regulation of lipogenesis and adipogenesis. Lipogenesis, the process of converting carbohydrates into fatty acids, and adipogenesis, the formation of fat cells, are crucial for fat storage. Gut microbiota can modulate these processes by influencing the expression of genes involved in lipid metabolism. For example, SCFAs like acetate serve as substrates for de novo lipogenesis in the liver. Additionally, gut microbiota can affect the expression of genes involved in fat storage and breakdown, further impacting body weight and fat distribution [7].

Dietary interventions can alter gut microbiota composition and, consequently, metabolic pathways. Diets high in fiber, fruits, and vegetables promote the growth of beneficial gut bacteria and increase SCFA production, which can improve metabolic health and reduce obesity risk. Conversely, diets high in fat and sugar can decrease gut microbiota diversity and promote the growth of bacteria associated with obesity. Probiotics and prebiotics, which enhance the growth of beneficial bacteria, have shown potential in modulating gut microbiota and improving metabolic outcomes. However, the efficacy of these interventions can vary based on individual microbiota compositions and genetic factors [8, 9].

The gut-brain axis, a bidirectional communication system between the gut and the brain, also plays a role in the interplay between gut microbiota and obesity. Gut bacteria produce various metabolites and neurotransmitters that can influence brain function and behavior, including appetite regulation and energy expenditure. For instance, certain gut bacteria produce gamma-aminobutyric acid (GABA), a neurotransmitter that can affect food intake and stress responses. Dysregulation of the gut-brain axis can lead to altered appetite and feeding behaviors, contributing to obesity [10].

Conclusion

The interplay between gut microbiota and metabolic pathways is complex and multifaceted, significantly influencing the development and progression of obesity. Gut microbiota modulate host metabolism through SCFA production, bile acid metabolism, inflammation, lipogenesis, and the gut-brain axis. Dietary interventions and modifications of gut microbiota composition hold promise for preventing and treating obesity. However, more research is needed to fully understand the specific microbial pathways involved and to develop targeted therapies that can effectively modulate gut microbiota and improve metabolic health. Understanding these intricate relationships could lead to innovative strategies for combating obesity and enhancing overall well-being.

References

  1. Musso G, Gambino R, Cassader M. Interactions between gut microbiota and host metabolism predisposing to obesity and diabetes. Annu Rev Med. 2011;62(1):361-80.

    2. Indexed at, Google Scholar, Cross Ref

  2. Tremaroli V, Bäckhed F. Functional interactions between the gut microbiota and host metabolism. Nature. 2012;489(7415):242-9.

    3. Indexed at, Google Scholar, Cross Ref

  3. Tilg H. Obesity, metabolic syndrome, and microbiota: multiple interactions. J Clin Gastroenterol. 2010;44:S16-8.

    4. Indexed at, Google Scholar, Cross Ref

  4. Gasmi A, Mujawdiya PK, Pivina L, et al. Relationship between gut microbiota, gut hyperpermeability and obesity. Curr Med Chem. 2021;28(4):827-39.

    5. Indexed at, Google Scholar, Cross Ref

  5. Duca F, Gerard P, Covasa M, Lepage P. Metabolic interplay between gut bacteria and their host. Front Horm Res. 2014;42:73-82.

    6. Indexed at, Google Scholar, Cross Ref

  6. Hartstra AV, Nieuwdorp M, Herrema H. Interplay between gut microbiota, its metabolites and human metabolism: Dissecting cause from consequence. Trends Food Sci Technol. 2016;57:233-43.

    7. Google Scholar

  7. Xu WT, Nie YZ, Yang Z, et al. The crosstalk between gut microbiota and obesity and related metabolic disorders. Future Microbiol. 2016;11(6):825-36.

    8. Indexed at, Google Scholar, Cross Ref

  8. Lee CJ, Sears CL, Maruthur N. Gut microbiome and its role in obesity and insulin resistance. Ann N Y Acad Sci. 2020;1461(1):37-52.

    9. Indexed at, Google Scholar, Cross Ref

  9. Shen J, Obin MS, Zhao L. The gut microbiota, obesity and insulin resistance. Mol. Asp. Med. 2013;34(1):39-58.

    10. Google Scholar

  10. Pothuraju R, Sharma RK. Interplay of gut microbiota, probiotics in obesity: a review. Endocr Metab Immune Disord Drug Targets. 2018;18(3):212-20.

    11. Indexed at, Google Scholar, Cross Ref

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