Food is a basic need for our survival and well-being. However, diet is not only essential to keeping us alive and healthy, but it also powers the whole microbial army that colonise our digestive tracts. This army is commonly known as gut microbiota and includes trillions of microbial soldiers (1) characterised by different “nutritional preferences”. These preferences are in the form of type, quality and even the origin of the food, ultimately influencing the strength of these army ranks.

Certain types of dietary fibre called prebiotics are especially tasty for good microbial forces, which converts fibre into smaller and high beneficial compounds. This process is named fermentation and the example of such advantageous end products are short-chain fatty acids (SCFAs). SCFAs are known for regulating a normal function of immune system (2-4), maintaining a well-functioning gut wall (5-7) and creating a cosy environment for other friendly bacteria (8). The latter enables an increasing number of allies, which can actively outperform microbes that cause diseases (aka pathogens). This action is called “competitive exclusion” and prevents pathogens from invading or growing out in our guts.

All of these actions together prevent the development of chronic inflammatory diseases such as inflammatory bowel disease, Crohn’s disease, rheumatoid arthritis, asthma etc. (9). Additionally, SCFAs can also reach other organs, such as the brain, where they are able to diminish neuroinflammatory responses that are known to underlie many neurodegenerative diseases (10).

Furthermore, microbial processing of fibre also has other effects on its fermentation. Namely, dietary fibres can be an excellent means of transport for some micronutrients to the gut.  When such minerals as copper, calcium, and zinc reach this destination, they are released when the fibre is utilised by the colonic bacteria (11). Their absorption is additionally increased in the environment of low pH created by, among others, SCFAs (12). It is also worth noting that some of these minerals possess anti-microbial properties, which further supports our microbial army in the prevention from various infections.

To sum up, the gut microbiome plays a critical role in our health. We can even say that microbiome modulates immune responses in a manner that dictates our health status. Imbalances in the gut microbiota may therefore dysregulate immune responses and lead to the development of chronic inflammatory dysfunctions or potentially make us more vulnerable to infections. That’s why it is important to take good care of our gut. And this starts with what we eat. 

References

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5. Willemsen LEM et al. Short chain fatty acids stimulate epithelial mucin 2 expression through differential effects on prostaglandin E1 and E2 production by intestinal myofibroblasts. Gut. 2003 Oct; 52(10): 1442–1447.
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11. Bergman, C.J., Gualberto, D.G., and Weber, C.W. (1997). Mineral binding capacity of dephytinized insoluble fiber from extruded wheat, oat and rice brans. Plant Foods Hum. Nutr. 51, 295–310.
12. Baye, K., Guyot, J.P., and Mouquet-Rivier, C. (2017). The unresolved role of dietary fibers on mineral absorption. Crit. Rev. Food Sci. Nutr. 57, 949–957.