Getting to know your gut system

Series: Gut Health

Article no.: 1

Highlight

• Our gut is made up of the digestive organs – mouth, esophagus, stomach, pancreas, gallbladder, liver, small & large intestines, rectum, and anus.
• Gut microbiota/microbes: a collection of different microorganisms residing in our gut.
• Gut microbiome: an ecosystem that consists of all the genetic materials of all the microorganisms in our gut. 
• The status of our gut microbiome can affect our brain & overall health through their tight connection in the nervous system.
• Things that can affect the status of our gut health include stress level, diet quality, infections, medications, and intake of pre & probiotics.
• The 2 most commonly used probiotics are Lactobacillus & Bifidobacterium. Both of them elicit various health benefits when consumed regularly.

1. Introduction

Chances are, you might have heard of gut health being mentioned somewhere and it intrigues you to know more. Throughout your life, when you experience gut-related issues, they usually go away without much complications afterwards. So what’s the big deal with it? After all, it’s just your stomach and intestines right?

2. What is actually in our gut?

Our gut is more than just the stomach and intestines – it consists of the whole digestive system starting from the mouth down to the anus. In between those two organs are esophagus, stomach, gallbladder, pancreas, liver, the small & large intestines, and rectum. Although the food we eat does not necessarily go through some of the organs like liver and pancreas, it is still affected by the chemicals secreted by those organs. And because a huge part of our torso consists of digestive organs, it makes sense that the digestive system can affect our body in so many ways. In fact, if we were to look at it from another perspective, humans are actually hollow beings that process food on a daily basis!

Beside all those organs, there is actually another important element that makes up our gut. It is not an organ but it is in fact one of the major elements that influences our gut health (and overall health too!).

Have you heard of gut microbiomes?

3. What is the gut microbiome?

Essentially, gut microbicrobiome is an ecosystem in our large intestine that consists of all the genetic materials of the microorganisms there. It consists of things such as prebiotics, probiotics, postbiotics, bacteria, fungi, protozoa, and even viruses. Both good and bad microorganisms exist in this environment.

These tiny organisms carry a myriad of functions such as breaking down certain types of sugar & fiber that our digestive organs cannot process. Our immune system is also partly regulated by them, especially when fighting harmful bacteria & viruses that invade our guts. On top of that, it has been claimed that our gut microbiome can also help to combat depression and prevent obesity. ^1,2

The importance of the microbiome in our gut extends beyond our digestive system actually. Their dynamic down there also influences our hormonal balance and our organs’ functions, especially our brain. In fact, many psychological issues have been linked to impaired gut health and vice versa. (Look out for our next article to know more about the gut-brain relationship!)

4. Things that affect our gut health

The microbes in our guts are affected with almost every part of our lifestyle. Like many other living things, they can die too, and if too many of them were wiped out, our health may deteriorate. The following are some of the things that can affect the health status of our gut:

A. Stress level ³

Psychological stress that we experience can alter our gut microbiota through our hormonal system. The higher the level of stress we’re exposed to, the more alteration will happen to our gut microbiome.

It might sound paradoxical, but because our gut microbiome plays a critical role in modulating stress, one of the best ways to combat your stress is actually by improving your gut health.

 

B. Diet type & quality ^4,5,6

I mean, duhh, of course what we eat will affect our gut health. But really, how?

If you follow a dietary habit that reflects the western or American diet, you are more likely damaging your intestinal bacterial balance. Diet high in animal-based fat and low in fiber reduces the population of good bacteria such as A. muciniphila and Lactobacillus.

On the other hand, a diet that is rich in plant-based food will help to increase the diversity of the microbes. The fiber in fruits & veggies will become the source of energy & nutrients for the bacteria, and will improve our bowel movement.

On top of that, it is also important to diversify your diet, especially with whole foods. Eating different types of food every day ensures a healthy & diverse microbial population.

 

C. Infections ⁷

When we contract an infection, our gut microbiota will be majorly altered. Sometimes, the pathogens (bad bacteria/microbes) can even outnumber & compete with the host bacteria in our intestine. As a result, infectious bacteria will reside in our gut and cause many other health issues.

D. Medication or drug use ⁸

 The use of certain medications like antibiotics & proton pump inhibitors can cause a disruption to our gut microbiome . Antibiotics specifically may wipe out an entire species of good bacteria from our digestive system which in turn, lowers our immunity, impairs our digestion, and disrupts our hormonal balance.

E. Intake of prebiotics & probiotics ⁹

• • Prebiotics – a type of insoluble fiber that our body cannot break down, but is used by the good bacteria in our gut.
  • Probiotics – a group of live microorganisms that are naturally present in our gut. They are promoted to have health benefits upon consumption.

There have been many health benefits linked to the intake of pre & probiotics, especially in the topic of gut health. Food such as whole grains, cruciferous vegetables, and legumes contain a good source of prebiotics, whereas fermented food such as yogurt, kombucha, kimchi, and sauerkraut contains the natural source of probiotics.

Although it is deemed as good for you, you need to be aware that not all probiotics were made the same. Food-based probiotics like the ones above consist of different bacterial strains than the ones manufactured in the lab. Both are generally safe for consumption but it’s important to know their differences so you can get the health benefits you desire.

Two of the most common bacteria strains that can be found in our intestine are lactobacillus & bifidobacterium. Some of the health benefits of the bacteria are shown in the table below:

Lactobacillus 10	Bifidobacterium 11
Modulate the immune system	Improve gastrointestinal conditions
Potentially able to reduce allergies risks	Alleviate allergies
Reduce free radicals species	Alleviate infectious, immunological diseases
Provide protection against harmful pathogens	Modulate the overall gut microbiome

References

1. Liu, R. T., Walsh, R. F. L., & Sheehan, A. E. (2019). Prebiotics and probiotics for depression and anxiety: A systematic review and meta-analysis of controlled clinical trials. Neuroscience & Biobehavioral Reviews, 102, 13–23. https://doi.org/10.1016/j.neubiorev.2019.03.023
2. Cunningham, A. L., Stephens, J. W., & Harris, D. A. (2021). A review on gut microbiota: A central factor in the pathophysiology of obesity. Lipids in Health and Disease, 20(1). https://doi.org/10.1186/s12944-021-01491-z
3. Kennedy, P. J. (2014). Irritable bowel syndrome: A microbiome-gut-brain axis disorder? World Journal of Gastroenterology, 20(39), 14105. https://doi.org/10.3748/wjg.v20.i39.14105
4. Singh, R. K., Chang, H.-W., Yan, D., Lee, K. M., Ucmak, D., Wong, K., Abrouk, M., Farahnik, B., Nakamura, M., Zhu, T. H., Bhutani, T., & Liao, W. (2017). Influence of diet on the gut microbiome and implications for human health. Journal of Translational Medicine, 15(1). https://doi.org/10.1186/s12967-017-1175-y
5. Makki, K., Deehan, E. C., Walter, J., & Bäckhed, F. (2018). The impact of dietary fiber on gut microbiota in host health and disease. Cell Host & Microbe, 23(6), 705–715. https://doi.org/10.1016/j.chom.2018.05.012
6. Heiman, M. L., & Greenway, F. L. (2016). A healthy gastrointestinal microbiome is dependent on dietary diversity. Molecular Metabolism, 5(5), 317–320. https://doi.org/10.1016/j.molmet.2016.02.005
7. Pham, T. A., & Lawley, T. D. (2014). Emerging insights on intestinal dysbiosis during bacterial infections. Current Opinion in Microbiology, 17, 67–74. https://doi.org/10.1016/j.mib.2013.12.002
8. Francino, M. P. (2016). Antibiotics and the human Gut microbiome: Dysbioses and accumulation of resistances. Frontiers in Microbiology, 6. https://doi.org/10.3389/fmicb.2015.01543
9. Kxnskx
10. Lactobacilli are particularly characterized in this regard, being associated with protection from pathogenic bacteria, modulation of the immune system to potentially reduced risk of allergies and cancer, reduction of radical oxidative species and cholesterol levels, and potentially benefiting in diabetes.
11. Wong, C. B., Odamaki, T., & Xiao, J.-zhong. (2019, February 8). Beneficial effects of Bifidobacterium LONGUM Subsp. LONGUM BB536 on human health: Modulation of gut microbiome as the PRINCIPAL ACTION. Journal of Functional Foods. https://www.sciencedirect.com/science/article/pii/S1756464619300684.