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Writer's pictureDr Joel Yong

Now, On The Topic Of Those Bugs That Live In Your Intestines…

Updated: Oct 24, 2020

They do so many things that you’d just go nuts just thinking about what they do!

Our intestines are long, and they contain a big load of live bacterial microorganisms — approximately 100 trillion of them at any one time.

These microbes comprise a diverse array of strains and species. Collectively, we know it as our gut microbiota, microbiome or microflora.

We have both our small and large intestines. As their environments are markedly different, different strains and species will tend to dominate the populations in those different regions.


For example, Lactobacillus species are predominantly found in the small intestine, while Bifidobacterium species tend to prefer being in the large intestine. Also, different strains and species will possess different adherence capabilities to the mucus linings of our intestines. The population counts of the bacteria in our guts can influence many different functions in the body, which we may know or not know about. Here’s how they can influence our body.

 

1. They affect our digestive health

That’s the most obvious one. They help to break down food particles in our gut. Our digestive system produces lactase enzymes to break down lactose, for one. When we aren’t producing enough lactase, the bacteria in our gut take over and break down the lactose into methane gas, hydrogen gas and other short chain fatty acids, which then results in symptoms of lactose intolerance, such as bloating, cramps, flatulence and loose stools. The short chain fatty acids that are produced in the gut are channelled elsewhere within the body to support other cell functions. What other enzymes are involved in digestion? Do check out What Does It Take To Get Food Digested In Our Bodies? for more information!

 

2. They affect our immune system functions

Our immune systems consist of a subset of cells known as the T helper (Th) cells. They exist as a balanced population, and newly synthesised Th cells can differentiate into any of the different Th cell types. When in balance, these T cells produce biochemical signals that protect the body from viruses (Th1), parasites (Th2) and fungi (Th17). Another type of Th cell is the regulatory cell (Treg), which helps to balance out the signalling activities of the Th1, Th2 and Th17 cells.

Of course, when Th cell activity is imbalanced, then problems start to arise. For example, excessive Th2 signalling activity is implicated in allergic reactions, while excessive Th17 activity gives rise to the development of autoimmune disorders.

The introduction of certain probiotic strains and species into one’s gut does bring about changes in Th cell activity, as evidenced here and here, among many other sources. These studies would indicate that a change up in one’s gut bacteria does aid in changing up one’s immune system responses — provided the right strains of bacteria are being used. These studies would also indicate that one’s gut microbiome isn’t that properly balanced, which is why they are experiencing those symptoms of suboptimal immune system function as well.

 

3. They affect our mental faculties

It was concluded in this article that:

Evidence from models of multiple sclerosis and stroke suggested that changes in the gut microbiota may indirectly influence the central nervous system via effects on immune homeostasis and immune responses. In support of a vagus-nerve mediated route for gut-derived signals, severing the vagus nerve below the diaphragm blocked the anxiolytic and gene expression effects of L. rhamnosus (JB-1).

Therefore, the gut microbiota first influences our immune system functions, which then results subsequently in the brain being affected. In fact, the gut microbiota does play a big role between our responses to stress, depression and anxiety too.

 

4. They affect our abilities to deal with chronic inflammatory diseases

Studies of the human gut have shown that the gut microbiota changes up significantly from healthy people to people who suffer from Type 2 diabetes, cardiovascular disease or even Alzheimer’s disease.

It isn’t really that surprising, especially since I have shown in these 2 articles just how a dysregulated immune system’s inflammatory response can contribute to the development of:

But how exactly does our lifestyle affect our gut microbiota populations?

I do discuss Four Ways That Our Lifestyle Affects Our Immune System. These four ways include:

  1. Our diet. What we eat enters our intestines and feeds the gut microbiota populations that live in the gut. If we eat more of the unhealthy foods consistently, our gut microbiota can get affected. You can see what a 10 day diet of nothing but McDonald’s can do to a person’s gut microbiota here. That also includes the consumption of antibiotics, which wipe out most (but not all) of the gut microbiota. What food we consume after the course of antibiotics will determine what species will repopulate the gut most quickly. The consumption of different probiotics supplements can also affect the gut microbiota species populations.

  2. Our sleep quality. A poor sleep quality can also induce significant changes in the gut microbiota. Given that at least 11% of all American adults report getting insufficient sleep every night, what do you think it is doing to their gut health and their susceptibility to immune system related issues then?

  3. Exercise also causes the gut microbiota to change up, and is independent of diet. Getting in good quality exercise is also key to supporting gut health!

  4. Our stress management. Stress can cause problems to the gut in two ways, as highlighted in this article:

Psychological stress and depression can promote consumption of highly palatable foods, influencing which gut bacteria thrive. Additionally, stress and depression can reshape the gut bacteria’s composition through stress hormones, inflammation, and autonomic alterations. In turn, the gut bacteria release metabolites, toxins, and neurohormones that can alter eating behavior and mood. Some bacterial species may encourage dysregulated eating.

In other words, they influence our gut microbiota internally via the release of different biochemical signallers. Some of these signallers will end up causing us to change up our eating behaviours and go for more unhealthy comfort foods, which then cause our diet to change up and affect our gut microbiome as such!

Not surprisingly, the four ways that our lifestyle choices can affect our immune system are also four ways that our gut health can be affected. The link between gut health and healthy immune system responses can be further strengthened as such.


Living a healthy lifestyle is key to supporting a healthy gut, a healthy immune system and a healthy brain. But how many people are even able to do that today?

If probiotics are necessary to support gut health, do choose the right products containing strains that are checked and verified to contain only what their labels state that they contain, and nothing else that can otherwise be detrimental to gut health.

Choose the right strains — that contain the Lactobacillus rhamnosus GG (LGG) strain, for instance, can be highly beneficial to gut health, much more so than strains such as Lactobacillus casei shirota (LCS), which is found in cultured drinks such as Yakult. Mainly because LGG has a much higher adhesion capability to the intestinal mucous linings than LCS does. As a result, it stays in the gut longer, can colonise the gut better, and provide more gut health benefits than LCS does. And it’s clinically proven to do so.

Products that contain LGG? The one that I use at the very least, of course. Verified to contain 100% of its tested strains too. Have a gander at it over at this shopping link!

 

This article was originally published on Medium.



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