Dysbiosis

Definition

Dysbiosis is a disruption in the composition, diversity, or function of a microbial community, especially the gut microbiota, in ways that are associated with impaired host health. It does not refer to a single universal microbial pattern, but to a shift away from a stable host-microbe relationship. [1] [2] [3]

Why It Matters in Ageing Research

Dysbiosis matters because the gut microbiome interacts with immune function, metabolism, inflammation, barrier integrity, and other systems that change with age. Age-related disruption of host-microbe balance is increasingly studied as part of ageing biology, although microbiome patterns vary widely between individuals and dysbiosis alone is not a complete measure of biological age. [4] [5] [6]

Common Confusion

• Dysbiosis is not the same as having one specific “bad” microbe.
• A microbiome association with disease does not always prove that the microbiome caused the disease.
• There is no single universal definition of a perfect healthy microbiome for every person.

Related Reading

• Hallmarks of Ageing
• Inflammaging
• Biological Age

References

1. Petersen, C., & Round, J. L. (2014). Defining dysbiosis and its influence on host immunity and disease. https://doi.org/10.1111/cmi.12308
2. Hooks, K. B., & O'Malley, M. A. (2017). Dysbiosis and Its Discontents. https://doi.org/10.1128/mBio.01492-17
3. Sommer, F., & Bäckhed, F. (2013). The gut microbiota — masters of host development and physiology. https://doi.org/10.1038/nrmicro2974
4. Lopez-Otin, C., et al. (2023). Hallmarks of aging: An expanding universe. https://doi.org/10.1016/j.cell.2022.11.001
5. O'Toole, P. W., & Jeffery, I. B. (2015). Gut microbiota and aging. https://doi.org/10.1126/science.aac8469
6. Ghosh, T. S., et al. (2022). Microbial signatures of healthy aging. https://doi.org/10.1038/s43587-021-00151-2