Scientect

Author: Muganti Rajah Kumar
Affiliation: Co-Editor (Biotechnology, Cell Biology & Biomolecular Sciences), Scientect
Date: 27th January 2025

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The gut is often referred to as the second brain because it contains over 100 million neurons, more than the spinal cord, and can function independently of the central nervous system (Thorley, 2016).

This means the gut has its own nervous system, which is known as the enteric nervous system (ENS). Furthermore, our gut hosts trillions of bacteria, fungi, viruses, and other microorganisms.

Living symbiotically, they play vital roles in regulating digestion, the immune system, metabolism, and even brain function. These diverse microbes collectively form what we call the gut microbiome.

The Key Functions of the Gut Microbiome

Digestion: The gut microbiome helps break down complex carbohydrates, proteins, and fats that our body cannot digest on its own. Certain gut bacteria produce enzymes to digest specific types of food, enabling better nutrient absorption from our diet. For example, Bacteroides produce polysaccharide-degrading enzymes, breaking dietary fiber into short-chain fatty acids (SCFAs) like butyrate, propionate, and acetate (Lapébie et al., 2019). These SCFAs play an essential role in providing energy for intestinal cells and maintaining overall gut health.

Immune system: The gut microbiome plays a major role in regulating the immune system. For example, certain bacteria, such as Faecalibacterium prausnitzii produce butyrate, an anti-inflammatory metabolite that helps maintain the intestinal barrier and modulates immune responses (Zhou et al., 2018). By producing such compounds, the gut microbiome prevents harmful pathogens from invading and stimulates the production of immune cells to protect the body from infections and diseases, including inflammatory bowel disease and irritable bowel syndrome.

Metabolism: The gut microbiome contributes to metabolism by producing essential compounds such as vitamins and SCFAs. For instance, specific strains of Bifidobacterium synthesize B vitamins, which play a crucial role in energy production and cellular function (LeBlanc et al., 2013). This metabolic activity helps maintain a healthy energy balance and supports overall metabolic health.

Brain function: Did you know that the gut microbiome communicates directly with our brain? These microorganisms and the brain interact through the gut-brain axis, a bidirectional communication system that regulates mood, behaviour, and cognitive functions. For example, certain gut bacteria such as Lactobacillus and Bifidobacterium produce neurotransmitters like gamma-aminobutyric acid (GABA), which influence mood and reduce anxiety (Yunes et al., 2016). Additionally, the gut produces more than 90% of serotonin, a neurotransmitter essential for regulating emotions, sleep, and appetite (Thorley, 2016). This highlights the critical role of the gut in supporting optimal brain function and overall mental health.

Why Gut Health Matters

A healthy gut hosts a diverse range of beneficial microorganisms that offer numerous advantages to us as their host. A healthy gut can keep us energetic, mentally clear, and emotionally balanced while also reducing the frequency of illnesses. On the other hand, an unhealthy gut characterized by fewer beneficial bacteria and more harmful microorganisms can lead to various physical and mental health issues, including Alzheimer’s disease, autoimmune conditions, diabetes, anxiety, and depression.

While a healthy gut microbiome supports our well-being, certain factors can disrupt this balance. Let’s explore what harms it and how we can nurture it back to health.

What Makes a Gut Unhealthy?

Certain lifestyle and dietary choices can harm the gut microbiome. A diet high in processed foods, sugars, and saturated fats can increase oxidative stress and inflammation in the gut, disrupting the balance of beneficial microorganisms. Additionally, exposure to environmental pollutants and poor lifestyle habits, such as chronic stress, a sedentary lifestyle, and lack of sleep, can negatively affect gut health.

How Can We Support a Healthy Gut?

1. A diet rich in diverse, nutrient-dense foods can help the gut microbiome thrive.
2. Consuming prebiotics, which are found in foods like garlic, onions, and bananas, helps support the growth of beneficial bacteria.
3. Eating probiotics, present in fermented foods like yogurt, kefir, and kimchi, also promotes this growth.
4. Including fiber-rich foods and avoiding overly processed options can also foster a healthier gut.

Uncovering the gut microbiome is a fascinating journey that connects food, health, and science in ways we’re only beginning to understand. In my next article, I’ll explore how specific foods impact our gut microbiome and what that means for our overall health. What foods do you think have the biggest impact on gut health? If this topic excites you as much as it does me, feel free to reach out. I’d love to hear your thoughts and have meaningful discussions!

References

1. Lapébie, P., Lombard, V., Drula, E., Terrapon, N., & Henrissat, B. (2019). Bacteroidetes use thousands of enzyme combinations to break down glycans. Nature Communications, 10(1), 2043. https://doi.org/10.1038/s41467-019-10068-5
2. LeBlanc, J. G., Milani, C., de Giori, G. S., Sesma, F., van Sinderen, D., & Ventura, M. (2013). Bacteria as vitamin suppliers to their host: A gut microbiota perspective. Current Opinion in Biotechnology, 24(2), 160–168. https://doi.org/10.1016/j.copbio.2012.08.005
3. Thorley, J. (2016). Gut feelings. The Lancet Gastroenterology & Hepatology, 1(1), 14. https://doi.org/10.1016/S2468-1253(16)30037-1
4. Yunes, R. A., Poluektova, E. U., Dyachkova, M. S., Klimina, K. M., Kovtun, A. S., Averina, O. V., Orlova, V. S., & Danilenko, V. N. (2016). GABA production and structure of gadB/gadC genes in Lactobacillus and Bifidobacterium strains from human microbiota. Anaerobe, 42, 197–204. https://doi.org/10.1016/j.anaerobe.2016.10.011
5. Zhou, L., Zhang, M., Wang, Y., Dorfman, R. G., Liu, H., Yu, T., Chen, X., Tang, D., Xu, L., Yin, Y., Pan, Y., Zhou, Q., Zhou, Y., & Yu, C. (2018). Faecalibacterium prausnitzii Produces Butyrate to Maintain Th17/Treg Balance and to Ameliorate Colorectal Colitis by Inhibiting Histone Deacetylase 1. Inflammatory Bowel Diseases, 24(9), 1926–1940. https://doi.org/10.1093/ibd/izy182