Diseases / Disorders & Gut microbiota

The diverse and complex human microbiome can hinder identifying clear links between the gut microbiome and specific diseases, complicating the translation of preclinical findings into human studies. This often leads to inconsistent or suboptimal results, especially in noncommunicable chronic disorders (NCDs).
Porcari et al. 2025 Cell 188: 2836

The human microbiome plays a crucial role in our understanding of health and disease. Researchers have noticed systematic differences in the microbiome's composition when comparing healthy individuals to those suffering from conditions linked to microbiota, such as colorectal cancer (Bullman et al. 2017; Hale et al. 2018 Genome Med 10: 78; Burns et al. 2018 PLoS Genet 14: e1007376) and inflammatory bowel disease (Matsuoka & Kanai 2015 Semin Immunopathol 37: 47-55). These observations highlight the significance of understanding what causes variations in the microbiome.
Abdill et al. 2025 Cell 188: 1100-1118

More than 20 receptors that face the luminal contents are potential therapeutic targets for diabetes, adiposity/obesity and digestive disorders

Fecal microbiota transplantation (FMT) experiments in animals and humans have been demonstrated the causal relationships between the gut microbiota and the pathogenesis of multiple diseases in humans
Li et al. 2021p Respir Res 22: 274

The intestinal microbiota is closely related to the occurrence and evolution of various diseases
Rastogi et al. 2020 International Journal of Molecular Sciences 21(9): 3212
Gutiérrez-Salmerón et al. 2021 Endocrine-Related Cancer 28(6): R173–R190
Tzeng et al. 2021 Genome Medicine 13(1): 2021

Differences in the underlying microbiome, specifically the ability to degrade fibers to generate SCFAs, might be a better predictor of disease incidence than diet alone
Wolter et al. 2021 Nat Rev Gastroenterol Hepatol 18(12): 885-902

Diseases / Disorders inside and outside the intestine are closely related to the changes in the abundance of Bifidobacterium longum
Yao et al. 2021 Journal of Immunology Research 2021: Article ID 8030297

Association studies have shown changes in the beta-diversity of the gut microbiota in individuals with various diseases
Sampson et al. 2016 Cell 167: 1469-1480
Crusell et al. 2018 Microbiome 6: 89
Vich Vila et al. 2018 Sci. Transl. Med.10: eaap8914
Kurilshikov et al. 2019 Circ Res 124: 1808-20
Lloyd-Price et al. 2019
Thomas et al. 2019a Nat Med 25: 667-78
Wang & Xu 2019 BMC Genomics 20: 124
Zhou et al. 2019h Nature 569: 663-71
Petersen et al. 2020 Nat Struct Mol Biol 27: 49-61

An increasing number of diseases have been characterised by distinctive changes in the composition and functionality of the gut microbiota
Allegretti et al. 2019 Lancet 394: 420-31

Changes in food production, dietary habits, antibiotic use, and lifestyle over the last century have led to significant changes in the microbiome and impacted human health in contradictory ways (De Filippo et al. 2010 Proc Natl Acad Sci USA 107: 14691-14696; Modi et al. 2014 J. Clin. Invest. 124: 4212–4218; Bolte et al. 2021 Gut 70: 1287–1298). The prevalence of acute infectious diseases has decreased, while it increased for chronic inflammatory diseases
Kasahara et al. 2018 Nat Microbiol 3:1461-1471

In addition, several dietary metabolites produced by gut bacteria have been identified as potential triggers of metabolic and cardiovascular diseases
Kasahara et al. 2018 Nat Microbiol 3:1461-1471

To determine if the microbiota plays a role in a specific disease, researchers can use a method called Fecal Microbiota Transplantation (FMT). This involves transferring the gut microbiota from a patient with the disease into an animal. The animal is then observed within a disease model to see if there are any changes.

Steps in the Process are:

• Fecal Microbiota Transplantation (FMT)


• Observation


• Comparison

Here, Fecal Microbiota Transplantation (FMT) means that the gut microbiota from a diseased patient is transplanted into an animal.

Observation means that the animal is observed to see if there are any changes in the disease model endpoints.

Comparison means, if the transplanted microbiota from the diseased patient causes changes, but microbiota from healthy controls do not, this suggests a potential link.

If introducing the identified bacteria or metabolites into the model results in similar changes, it suggests they are likely involved in causing the disease symptoms. This process helps pinpoint potential triggers and understand their role in disease development.
Strandwitz 2018 Brain Res. 1693(Pt B): 128-133

Studies in animal models also suggest a causative role of the microbiome in the development of non-communicable diseases (NCDs)
Valdes et al. 2018 BMJ 361: k2179

Gut Microbiota are involved in the pathogenesis of Diseases / Disorders not only in the Intestine but also in the Organs Located Distant from the Intestine
Ohtani 2015 Semin Immunopathol 37(1): 65-72

Disruption of the microbiota can contribute to several chronic pathologies, including Cancer / Tumors
Shreiner et al. 2015 Curr. Opin. Gastroenterol. 31: 69-75

Most Diseases / Disorders are associated with both a Western-type diet and dysbiosis
Walker & Lawley 2013 Pharmacol. Res. 69: 75-86

For a growing number of diseases, an altered microbiome is a marker of disease and actively contributes to pathology
Chassaing et al. 2012 Adv Immunol. 116: 93-112

In addition to association analyzes, intervention studies and animal studies have also demonstrated the causality of the gut microbiota concerning several diseases
Turnbaugh et al. 2006 Nature 444: 1027-31

To influence diseases through intestinal dysbiosis, a distinction must be made between local (intestinal effects) effects, i.e., effects related to the gastrointestinal tract (e.g., irritable bowel syndrome, digestive diseases) and effects on various distant body organs (extra-intestinal effects).

see also:
Analytic Microbiome / Methodology
Antibiotics & Dysbiosis
Cancer microbiome / Tumor microbiome & Colorectal cancer (CRC)
Cancer / Tumors & Dysbiosis
Cancer / Tumors & Gut microbiota
Colorectal Cancer (CRC) & Gut microbiota
Diseases / Disorders & Dysbiosis
Diseases / Disorders (extraintestinal manifestations)
Diseases / Disorders (extra-intestinal) & Gut microbiota
Diseases / Disorders (intestinal manifestations)
Diseases / Disorders (intestinal) & Gut Microbiota
Bacterial metabolites / Microbial metabolites & Diseases / Disorders
Energy source
Extraintestinal Manifestations
Gut bacteria
Gut microbiota & Immunity
Gut microbiota & Inflammatory Bowel Disease (IBD)
Gut microbiota & Influencing factors
Hygiene hypothesis
Industrialisation
Oncomicrobes