The gut microbiome is one of the most fascinating areas of nutrition science. We've all heard phrases like "go with your gut" and "trust your gut instincts"; but, what most people don't fully understand is how those words are actually describing the interplay between the microorganisms (bacteria) that live inside us and the physiological mechanisms within our own bodies.
Humans, acting as hosts, have co-evolved with microorganisms for hundreds of thousands of years, and each person's body has its own unique population of bacteria. Microorganisms live on our skin, in the corners of our eyes, in our fingernails and in our gut, and we live together symbiotically for much of the time.
Within the human gastrointestinal tract, also known as our gut, there is huge variability in the number, type, and function of bacteria; but many are located in the large intestines where they happily spend their time fermenting non-digestible food components. And we are able to benefit from their work! They break down these food pieces into nutrients we may not be able to otherwise access; and while this is extremely beneficial to us as hosts, this advantage is just one of the ways they influence our health.
Research has shown that the gut does not function all by itself. In fact, there is a complex bidirectional relationship with the Central Nervous System known as the gut–brain axis. This axis provides crosstalk between the gut and the brain, and we are learning more and more how the microorganisms within us are actually directing much of the conversation. The basic understanding is that an increase in the diversity of our gut bacterial population improves our health (via metabolic and immunological functions); while a reduction or alteration is associated with negative health effects.
"Our guts control and deal with every aspect of our health[...] how we digest our food, [...] our mood, behavior, energy, weight, food cravings, hormone balance, immunity, and overall wellness." - Bell, V., Ferrão, J., Pimentel, L., Pintado, M., & Fernandes, T. (2018)
It really is incredible just how integral and influential these microorganisms are when it comes to our health. Knowing this, it makes sense to strive toward building a microorganism population that is both dense and diverse, and there are a number of strategies we can use. Understanding the key influencers of biome health, along with some of the areas of impact by the gut microbiome is a great starting point. This series of blog posts (and videos) will delve further into biome health, but here is a basic breakdown of where we're heading.
What regulates the health of our gut microbiome?
environment
lifestyle
diet
age
genetics
Besides breaking down food particles in our gut, what else is impacted by bacteria?
Digestion
Cognition
Mood
Immunity
Next Up: "Influences on the Gut-Microbiome", "Impact of the Gut-Microbiome" and "Targeted Eating for Gut-Microbiome Health".
Biome Series References
1) Allen, A. P., Dinan, T. G., Clarke, G., & Cryan, J. F. (2017). A psychology of the human brain-gut-microbiome axis. Social and Personality Psychology Compass, 11(4). https://doi.org/10.1111/spc3.12309
2) Bear, T., Dalziel, J., Coad, J., Roy, N., Butts, C., & Gopal, P. (2021). The microbiome-gut-brain axis and resilience to developing anxiety or depression under stress. Microorganisms, 9(4), 723. https://doi.org/10.3390/microorganisms9040723
3) Bell, V., Ferrão, J., Pimentel, L., Pintado, M., & Fernandes, T. (2018). One health, fermented foods, and gut microbiota. Foods, 7(12), 195. https://doi.org/10.3390/foods7120195 Buford, T. W. (2017). (Dis)Trust your gut: The gut microbiome in age-related inflammation, health, and disease. Microbiome, 5(1). https://doi.org/10.1186/s40168-017-0296-0
4) Dąbrowska, K., & Witkiewicz, W. (2016). Correlations of HOST genetics and gut Microbiome COMPOSITION. Frontiers in Microbiology, 7. https://doi.org/10.3389/fmicb.2016.01357
5) Ghaisas, S., Maher, J., & Kanthasamy, A. (2016). Gut microbiome in health and disease: Linking the microbiome–gut–brain axis and environmental factors in the pathogenesis of systemic and neurodegenerative diseases. Pharmacology & Therapeutics, 158, 52–62. https://doi.org/10.1016/j.pharmthera.2015.11.012
6) Grosicki, G. J., Riemann, B. L., Flatt, A. A., Valentino, T., & Lustgarten, M. S. (2020). Self-reported sleep quality is associated with gut microbiome composition in young, healthy individuals: A pilot study. Sleep Medicine, 73, 76– 81. https://doi.org/10.1016/j.sleep.2020.04.013
7) Gui, X., Yang, Z., & Li, M. D. (2021). Effect of cigarette smoke on gut microbiota: State of knowledge. Frontiers in Physiology, 12. https://doi.org/10.3389/fphys.2021.673341
8) Hasan, N., & Yang, H. (2019). Factors affecting the composition of the gut microbiota, and its modulation. PeerJ, 7. https://doi.org/10.7717/peerj.7502
9) Lee, Y., & Kim, Y.-K. (2021). Understanding the connection between the gut–brain axis and stress/anxiety disorders. Current Psychiatry Reports, 23(5). https://doi.org/10.1007/s11920-021-01235-x
10) Monda, V., Villano, I., Messina, A., Valenzano, A., Esposito, T., Moscatelli, F., Viggiano, A., Cibelli, G., Chieffi, S., Monda, M., & Messina, G. (2017). Exercise modifies the gut microbiota with positive health effects. Oxidative Medicine and Cellular Longevity, 2017, 1–8. https://doi.org/10.1155/2017/3831972
11) Rizzello, F., Spisni, E., Giovanardi, E., Imbesi, V., Salice, M., Alvisi, P., Valerii, M. C., & Gionchetti, P. (2019). Implications of the Westernized diet in the onset and progression of IBD. Nutrients, 11(5), 1033. https://doi.org/10.3390/nu11051033 [Diet Pyramids Image]
12) Sandhu, K. V., Sherwin, E., Schellekens, H., Stanton, C., Dinan, T. G., & Cryan, J. F. (2017). Feeding the microbiota-gut-brain axis: Diet, microbiome, and neuropsychiatry. Translational Research, 179, 223–244. https://doi.org/10.1016/j.trsl.2016.10.002
13) Tu, P., Chi, L., Bodnar, W., Zhang, Z., Gao, B., Bian, X., Stewart, J., Fry, R., & Lu, K. (2020). Gut microbiome toxicity: Connecting the environment and gut microbiome-associated diseases. Toxics, 8(1), 19. https://doi.org/10.3390/toxics8010019
14) Wastyk, H. C., Fragiadakis, G. K., Perelman, D., Dahan, D., Merrill, B. D., Yu, F. B., Topf, M., Gonzalez, C. G., Van Treuren, W., Han, S., Robinson, J. L., Elias, J. E., Sonnenburg, E. D., Gardner, C. D., & Sonnenburg, J. L. (2021). Gutmicrobiota-targeted diets modulate human immune status. Cell, 184(16). https://doi.org/10.1016/j.cell.2021.06.01
Loved this! Very informative!