Gut Microbiota Through the Ages: How It Evolves Across a Lifetime

The human gut microbiota is a complex and dynamic ecosystem that evolves significantly over a person’s lifetime.

From infancy to old age, this microbial community undergoes remarkable changes influenced by diet, environment, hormonal fluctuations, and immune system activity.

Understanding how the microbiota changes with age is crucial for developing strategies to support lifelong health.

The gut microbiota begins forming at birth, with its initial composition influenced by factors such as delivery mode and feeding type. Babies born via vaginal delivery tend to have a microbiota dominated by Lactobacillus and Bifidobacterium, while those born via cesarean section often exhibit reduced microbial diversity (Dominguez-Bello et al., 2010).

Breastfeeding further promotes the growth of beneficial microbes by providing human milk oligosaccharides (HMOs) as prebiotics (Carr et al.,2021).

As solid foods are introduced during weaning, the microbiota transitions from a less diverse to a more complex ecosystem (B?ckhed et al., 2015).

This shift is essential for the development of the immune system and metabolic pathways, setting the stage for a stable microbiota in adulthood (Ira et al., 2024).

During puberty, hormonal changes, particularly in sex hormones, influence gut microbiota composition.

For example, estrogen and testosterone impact the relative abundance of specific bacterial species.

These changes are not only critical for gut health but also affect mood, metabolism, and immune function, highlighting the gut-brain axis’s role during this stage of life.

In older adults, the gut microbiota undergoes significant changes, often marked by reduced diversity and an increase in pathogenic and opportunistic microbes.

Lifestyle factors, dietary habits, and immune system aging (immunosenescence) further influence these changes.

According to Ira et al. (2024), these shifts are associated with frailty, chronic inflammation, and an increased risk of age-related diseases, such as cardiovascular disease and neurodegeneration.

The gut microbiota’s evolution across the human lifespan underscores its critical role in health and disease.

By adopting age-specific strategies to nurture this microbial ecosystem, we can improve quality of life and reduce the burden of chronic diseases.

References:

B?ckhed, F., Roswall, J., Peng, Y., Feng, Q., Jia, H., Kovatcheva-Datchary, P., Li, Y., Xia, Y., Xie, H., Zhong, H., Khan, M. T., Zhang, J., Li, J., Xiao, L., Al-Aama, J., Zhang, D., Lee, Y. S., Kotowska, D., Colding, C., Tremaroli, V., … Wang, J. (2015). Dynamics and Stabilization of the Human Gut Microbiome during the First Year of Life. Cell host & microbe, 17(5), 690–703. https://doi.org/10.1016/j.chom.2015.04.004

Carr, L. E., Virmani, M. D., Rosa, F., Munblit, D., Matazel, K. S., Elolimy, A. A., & Yeruva, L. (2021). Role of Human Milk Bioactives on Infants' Gut and Immune Health. Frontiers in immunology, 12, 604080. https://doi.org/10.3389/fimmu.2021.604080

Dominguez-Bello, M. G., Costello, E. K., Contreras, M., Magris, M., Hidalgo, G., Fierer, N., & Knight, R. (2010). Delivery mode shapes the acquisition and structure of the initial microbiota across multiple body habitats in newborns. Proceedings of the National Academy of Sciences of the United States of America, 107(26), 11971–11975. https://doi.org/10.1073/pnas.1002601107

Ira R, Adwani J, Krishnan AO, Subramanian G, Yadav S, Shukla S, et al. (2024). Understanding Aging through the Lens of Gut Microbiome. Exploratory Research and Hypothesis in Medicine, 9(4), 294-307. https://doi.org/10.14218/ERHM.2024.00008