The intestinal microbiota is the set of living microorganisms that inhabit our digestive tract, mainly the intestine. The best known are bacteria, but we also have fungi and even viruses.
We invite you to delve into the interesting world of the microbiota, which in addition to being of great importance for our digestive health, also has connections with such essential organs as the brain or our skin.
Composition of the gut microbiota
The microbiota is not homogeneous throughout the digestive tract. It follows a decreasing order, i.e. it is smallest in the oesophagus and stomach and increases as the end of the large intestine is approached. This is why most of the living micro-organisms are found in the intestine.
These bacteria are classified into large groups, the most abundant being Firmicutes and Bacteroidetes. Also, an excess of any of these bacteria can be troublesome to our gut; an example of this is an excess of Escherichia coli, which can lead to diarrhoea [1].
It is thought that there are more or equal numbers of viruses than bacteria in the gut. Although this may seem negative at first glance, this is not the case. Most of the viruses in our gut do not affect our cells, but are bacteriophages, i.e. they modulate our bacteria [1].
As for the amount of fungi in our gut, it is much smaller than bacteria or viruses, but they play a very important role, as they help to maintain the correct intestinal balance [1].
Functions of the gut microbiota
The gut microbiota is essential for maintaining gut health:
Firstly, microorganisms are a fundamental part of the so-called "gut barrier": this is the first line of defence against pathogens (disease-causing microorganisms) that can enter through food. In addition, the microbiota helps to degrade or process toxic substances such as mycotoxins, heavy metals or some food components, such as gliadin or casein, which can cause allergies. Another function of the microbiota in the gut is related to digestion, as there are food components such as microbiota-accessible carbohydrates (MACs) or fibre, which have to be processed by the microbiota in order for our bacteria to feed and obtain energy [1].
But we cannot overlook the many benefits it also has on the rest of the body:
Microbiota are also involved in regulating the function of other organs at a distance, such as the brain, skin, liver or lungs. These are the so-called "axes": gut-brain, gut-skin, gut-lungs, and so on. But how does it exercise this regulation? Through the manufacture of substances. The microbiota manufactures certain compounds, such as short-chain fatty acids, which help to mediate the action of the rest of the body's organs. It even manufactures vitamins such as K or B vitamins and certain neurotransmitters such as serotonin, which have an impact on the well-being of our entire organism [1].
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Did you know…? Intestinal bacteria also play a crucial role in the synthesis of anti-ageing molecules, such as senolytics, which help to eliminate accumulated ageing cells in the body. Examples of these molecules include urolithin A, obtained from the transformation of polyphenols from foods such as pomegranates by the microbiota. As well as spermidine, which is involved in the process of tissue cleansing through the process of autophagy [2]. |
Finally, it also regulates the state of our immune system, modulating its anti-inflammatory or pro-inflammatory state depending on the type of signalling it generates. This modulation begins with the immune system associated with the digestive mucosa, as the microbiota helps the immune system to distinguish what is self and what is foreign, i.e. what it has to defend us against [1].
Gut microbiota imbalances
Our microbiota is not always balanced, as there are different factors that can directly affect it. This imbalance in the microbiota is known as gut dysbiosis.
Gut dysbiosis is usually caused by an excess of pathogenic species due to an intestinal condition. The problem is that when some populations of microorganisms are in excess, other "good" bacteria are depleted, such as bifidobacteria or lactobacilli, leading to a decrease in bacterial diversity. This correlates with non-communicable diseases [1].
How to care for, improve and restore the balance of the intestinal microbiota
In order to have a healthy microbiota that ensures optimal health, several aspects of our lifestyle should be reviewed, in addition to considering the incorporation of probiotic supplements as an extra help:
- Diversify your diet: Studies have shown that a diet varied in nutrients leads to a more diverse microbiota, which is beneficial to health. Diversifying foods can increase the variety of beneficial microorganisms [3].
- Eat more fibre: Foods rich in fibre or MACs, such as fruits, vegetables and legumes, are excellent for the growth of beneficial bacteria. Fibre acts as a prebiotic, i.e. it is food for gut bacteria, providing them with energy so they can perform their functions properly [4].
- Include fermented foods: Fermented foods such as yoghurt, kefir, sauerkraut and kimchi contain healthy bacteria (probiotics) that can improve the composition of the gut microbiota, thus facilitating its functions [5].
- Incorporate healthy fats: Healthy fats such as omega-3, found in fish such as salmon and some seeds and nuts, are beneficial for our gut microbiota [6].
- Limit the use of antibiotics: Although antibiotics are necessary in certain situations, always under medical supervision, their excessive or inappropriate use can damage the microbiota. It has been shown that antibiotics can alter the diversity and composition of gut bacteria. For this reason, it is advisable to supplement the use of antibiotics with probiotics to help repopulate the microbiota after treatment [7].
- Avoid ultra-processed foods: Foods that are ultra-processed and high in sugars and fats can negatively alter the gut microbiota. Several studies have linked these diets to a decrease in bacterial diversity [8].
- Reduce stress: Because of the relationship between the brain and gut known as the brain-gut axis, stress can affect this axis and alter the microbiota. Practising stress reduction techniques such as meditation or yoga can be beneficial [9].
- Get enough sleep: Lack of rest or poor quality sleep can have negative effects on the gut microbiota. It is important to maintain a regular sleep routine and ensure quality sleep [10].
- Avoid alcohol consumption: Excessive alcohol can damage gut bacteria and disrupt the intestinal barrier. Limiting alcohol consumption is beneficial for the microbiota [11].
- Consider probiotic supplements: A varied diet can provide many benefits for the microbiota naturally, but in some cases probiotic supplements can be considered to more specifically boost the composition of our microbiota. It is essential to select probiotics with specific bacterial strains, as not all bacteria perform the same functions [1]. We recommend our Proactiflora and Proactiflora Premium, which you can read about in the following blog post. In addition, for an enhanced effect, we recommend combining these probiotics with other supplements such as Lion's Mane and Omega 3.
As you may have already realised, our health and wellbeing is fought in our gut, specifically in our gut microbiota. So if anyone asks you how to restore their health, the key is to have a healthy and balanced microbiota.
References:
[1] Arponen, Sari (2021). ¡Es la microbiota, idiota!. Alienta.
[2] Yu, L., Pan, J., Guo, M., Duan, H., Zhang, H., Narbad, A., Zhai, Q., Tian, F., & Chen, W. (2023). Gut microbiota and anti-aging: Focusing on spermidine. Critical reviews in food science and nutrition, 1–19. Advance online publication. https://doi.org/10.1080/10408398.2023.2224867.
[3] Strasser, B., Wolters, M., Weyh, C., Krüger, K., & Ticinesi, A. (2021). The Effects of Lifestyle and Diet on Gut Microbiota Composition, Inflammation and Muscle Performance in Our Aging Society. Nutrients, 13(6), 2045. https://doi.org/10.3390/nu13062045.
[4] Shi, H., Wang, Q., Zheng, M., Hao, S., Lum, J. S., Chen, X., Huang, X. F., Yu, Y., & Zheng, K. (2020). Supplement of microbiota-accessible carbohydrates prevents neuroinflammation and cognitive decline by improving the gut microbiota-brain axis in diet-induced obese mice. Journal of neuroinflammation, 17(1), 77. https://doi.org/10.1186/s12974-020-01760-1.
[5] Wieërs, G., Belkhir, L., Enaud, R., Leclercq, S., Philippart de Foy, J. M., Dequenne, I., de Timary, P., & Cani, P. D. (2020). How Probiotics Affect the Microbiota. Frontiers in cellular and infection microbiology, 9, 454. https://doi.org/10.3389/fcimb.2019.00454.
[6] Fu, Y., Wang, Y., Gao, H., Li, D., Jiang, R., Ge, L., Tong, C., & Xu, K. (2021). Associations among Dietary Omega-3 Polyunsaturated Fatty Acids, the Gut Microbiota, and Intestinal Immunity. Mediators of inflammation, 2021, 8879227. https://doi.org/10.1155/2021/8879227.
[7] Ramirez, J., Guarner, F., Bustos Fernandez, L., Maruy, A., Sdepanian, V. L., & Cohen, H. (2020). Antibiotics as Major Disruptors of Gut Microbiota. Frontiers in cellular and infection microbiology, 10, 572912. https://doi.org/10.3389/fcimb.2020.572912.
[8] Laudanno O. M. (2023). Changes in the microbiota due to ultra-processed foods: obesity, cancer and premature death. Medicina, 83(2), 278–282.
[9] Molina-Torres, G., Rodriguez-Arrastia, M., Roman, P., Sanchez-Labraca, N., & Cardona, D. (2019). Stress and the gut microbiota-brain axis. Behavioural pharmacology, 30(2 and 3-Spec Issue), 187–200. https://doi.org/10.1097/FBP.0000000000000478.
[10] Han, M., Yuan, S., & Zhang, J. (2022). The interplay between sleep and gut microbiota. Brain research bulletin, 180, 131–146. https://doi.org/10.1016/j.brainresbull.2021.12.016.
[11] Engen, P. A., Green, S. J., Voigt, R. M., Forsyth, C. B., & Keshavarzian, A. (2015). The Gastrointestinal Microbiome: Alcohol Effects on the Composition of Intestinal Microbiota. Alcohol research : current reviews, 37(2), 223–236.
