The lesser-known functions of the gut microbiome (and 4 ways you can improve yours)

When discussing the gut microbiome, its role in digestion and metabolism is the one that most commonly springs to mind. Indeed, one of the primary functions of the gut microbiome is to aid in the digestion and metabolism of dietary components that are otherwise indigestible. However, its role in other aspects of health is lesser known, and still today science is uncovering its profound impact. This article explores the lesser-known importance of the gut microbiome and what you can do to improve your own gut microbiome.

Immune function:

The gut microbiome interacts closely with the immune system, helping to distinguish between harmful pathogens and beneficial microorganisms. A balanced gut microbiome supports immune function, helping to defend against infections, allergies, and autoimmune diseases (Rinninella et al., 2019).

Gut-brain axis:

The gut-brain axis is a bidirectional communication pathway between the gut and the brain, facilitated by neural, hormonal, and immunological signals (Mayer et al., 2015). Emerging research indicates that the gut microbiome plays a crucial role in modulating brain function, mood, and behaviour. Additionally, abnormal gut microbiota variations are closely associated with the onset of several neurological disorders such as Parkinson’s disease, Alzheimer’s disease, and autism spectrum disorders (Rinninella et al., 2019). 

Metabolism and weight regulation:

The gut microbiome influences metabolism and weight regulation through its role in energy extraction, storage, and expenditure. Imbalances in the gut microbiota composition have been linked to obesity (Ley et al., 2005), metabolic syndrome, and insulin resistance. Promoting a healthy gut microbiome through dietary and lifestyle interventions may support weight management and metabolic health.

Disease prevention:

Imbalance in the gut microbiome (or dysbiosis), has been associated with numerous diseases such as diabetes (Pascale et al., 2019), cancer (Raza et al., 2019), irritable bowel syndrome (Bhattarai et al., 2017), cardiovascular diseases (Tang et al., 2019), and neurological disorders (Collins et al., 2012).

So what can I eat to nurture my microbiome?

While food is just one factor that influences the composition and function of the gut microbiome, dietary habits do have a profound impact on gut health (Rinninella et al., 2019).

1. Dietary fibre:

Multiple studies link high-fibre diets rich in fruits, vegetables, and whole grains to a more diverse and beneficial gut microbiota. Incorporating fibre-rich foods such as fruits, vegetables, legumes, and whole grains into your diet provides prebiotic fibres that nourish beneficial gut bacteria. Numerous studies reveal that significant health benefits can be obtained from prebiotics (Hills et al., 2019). Jerusalem artichokes, leeks, onions, garlic, bananas, and apples are all especially good food sources of prebiotics.

2. Fermented foods:

Fermented foods undergo a process that enhances their shelf life and creates beneficial probiotics. Including fermented foods like yogurt, kefir, tempeh, miso, and pickles in your diet can promote gut health and diversity (Leeuwendaal et al., 2022).

3. Limit processed foods and sugar:

Diets high in processed foods, sugar, and unhealthy fats may promote dysbiosis and inflammation in the gut (Rinninella et al., 2019. Highly processed foods, sugary snacks, and sweetened beverages can disrupt gut microbiota composition and promote inflammation (Hills et al., 2019). Opt for whole, minimally processed foods to support a healthy gut environment (Rinninella et al., 2019).

4. Intermittent fasting:

Intermittent fasting, longer multiday fasts, and fasting-mimicking diets have been shown to improve gut barrier function, increase microbial diversity, and reverse intestinal inflammation (Cignarella et al., 2018).

In summary, gut health is essential for supporting digestion, immune function, brain health, metabolism, and disease prevention. By nurturing a diverse and balanced gut microbiome through dietary interventions, individuals can optimise their long-term overall health and well-being.

Bhattarai, Y., Muniz Pedrogo, D. A., & Kashyap, P. C. (2017). Irritable bowel syndrome: a gut microbiota-related disorder? American Journal of Physiology-Gastrointestinal and Liver Physiology, 312, G52–G62. http://doi.org/10.1152/ajpgi.00338.2016. 

Cignarella, F., Cantoni, C., Ghezzi, L., Salter, A., Dorsett, Y., Chen, L., Phillips, D., Weinstock, G. M., Fontana, L., Cross, A. H., et al. (2018). Intermittent fasting confers protection in CNS autoimmunity by altering the gut microbiota. Cell Metabolism, 27, 1222–1235. http://doi.org/10.1016/j.cmet.2018.05.006. 

Collins, S. M., Surette, M., & Bercik, P. (2012). The interplay between the intestinal microbiota and the brain. Nature Reviews Microbiology,10, 735–742. http://doi.org/10.1038/nrmicro2876.

Hills, R. D., Jr, Pontefract, B. A., Mishcon, H. R., Black, C. A., Sutton, S. C., & Theberge, C. R. (2019). Gut microbiome: Profound implications for diet and disease. Nutrients, 11(7), 1613. https://doi.org/10.3390/nu11071613

Leeuwendaal, N. K., Stanton, C., O'Toole, P. W., & Beresford, T. P. (2022). Fermented foods, health and the gut microbiome. Nutrients, 14(7), 1527. https://doi.org/10.3390/nu14071527

Ley, R. E., Bäckhed, F., Turnbaugh, P., Lozupone, C. A., Knight, R. D., & Gordon, J. I. (2005). Obesity alters gut microbial ecology. Proceedings of the National Academy of Sciences of the United States of America, 102, 11070–11075. http://doi.org/10.1073/pnas.0504978102

Mayer, E. A., Tillisch, K., & Gupta, A. (2015). Gut/brain axis and the microbiota. Journal of Clinical Investigation, 125, 926–938. http://doi.org/10.1172/JCI76304.

Pascale, A., Marchesi, N., Govoni, S., Coppola, A., & Gazzaruso, C. (2019). The role of gut microbiota in obesity, diabetes mellitus, and effect of metformin: New insights into old diseases. Current Opinion in Pharmacology, 49, 1–5. http://doi.org/10.1016/j.coph.2019.03.011. 

Raza, M. H., Gul, K., Arshad, A., Riaz, N., Waheed, U., Rauf, A., Aldakheel, F., Alduraywish, S., Rehman, M. U., Abdullah, M., et al. (2019). Microbiota in cancer development and treatment. Journal of Cancer Research and Clinical Oncology, 145, 49–63. http://doi.org/10.1007/s00432-018-2816-0

Rinninella, E., Raoul, P., Cintoni, M., Franceschi, F., Miggiano, G. A. D., Gasbarrini, A., & Mele, M. C. (2019). What is the healthy gut microbiota composition? A changing ecosystem across age, environment, diet, and diseases. Microorganisms, 7(1), 14. https://doi.org/10.3390/microorganisms7010014

Tang, W. H. W., Bäckhed, F., Landmesser, U., Hazen, S. L. (2019). Intestinal microbiota in cardiovascular health and disease. Journal of the American College of Cardiology, 73, 2089–2105. http://doi.org/10.1016/j.jacc.2019.03.024.