Immunity. Most people probably think about good health or a healthy body when they hear this word.
Those who are more familiar with how the human body works know that immunity is a complex biological system within the body involving particular cells and biochemical processes. The immune system can recognize and tolerate whatever belongs to the human body (self) and reject/destroy what is foreign (non-self).
But did you know that bacteria living on your skin and in your body – your microbiome – is part of your immunity system? Without your microbiome, your immune system and health would be compromised. Recent studies have shown that bacteria serve an essential role in the proper development of the immune system.
Here are six ways how your microbiome is responsible for your immunity and health:
1. Your immune system tolerates early colonizing microbiota
I wrote an article in which I described how we obtain our microbiome after we’re born. The first microbiota colonizes our body from our mother’s vagina (normal birth) or skin (cesarean delivery). That microbiota, together with other microbes from mothers’ skin, doctors/nurses, and the environment we are born in, colonizes our skin and gut first. It is crucial because our body doesn’t have a fully evolved immune system at birth, and it embraces those early bacteria as innate bacteria. That is very good if the mother’s vagina contains healthy and balanced microbiota with probiotics, such as lactobacilli or bifidobacterium.
But if it contains not-so-ideal microflora? The child might acquire a tolerance for those bacteria anyway, and the immunity system will not be so active against those bacteria, even if they are not so beneficial. That can impact our immunity and health during our lifetime, positively or negatively.
2.Microbiome cooperates with immune cells and can manipulate immune system response.
Scientists consider the microbiome a virtual body organ because it has many crucial functions. One of them is our immunity. Bacteria directly cooperate with human immune cells and can affect immunity response.
Bacteria interact with the immune system through enzymes they are producing which are recognized by the immune system. Some bacteria also release substances that influence human immune cells, increasing or decreasing the numbers of immune cells or changing their function. The substances that can influence the immune system are called immunomodulatory molecules.
The beneficial influence of bacterial immunomodulatory molecules is not only in the intestines. The same interplay between immune cells and bacteria or substances they produce is present in the entire body, including the skin and various organs.
Probiotic bacteria can generally influence our immunity positively, but the opposite can be true for pathogens that are using a similar mechanism to program the immunity system to their advantage.
There are hundreds of different bacteria species, and each type of bacteria can affect the immune system in a specific way, meaning that the immune system can respond differently to the presence of each type of bacteria.
Some types of bacteria activate special immune system cells to release substances that cause an inflammatory response. It is important to understand that inflammation is a healthy immune system response, and its purpose is to create conditions to help the body fight off pathogens or toxins.
But sometimes, when the inflammatory response is too strong – in the case of dysbiosis and the presence of pathogens – it can lead to the development of inflammatory diseases, such as Crohn’s disease and colitis.
The healthy immune system needs to have a balance of cells—some that stimulate inflammation and some that calm it down.
A healthy and balanced microbiome is key to regulating the activity of the immune system and preventing diseases related to improper immune system functioning.
Many people with inflammatory or autoimmune conditions such as IBD, eczema, or even cancer think it is impossible to treat those conditions without drugs. The opposite is true.
3. Pioneer microbiota species prevent other bacteria from settling in
Just before birth, our body is almost sterile, containing no bacteria or any other cells than human cells. But as soon as we emerge into the world, microbiota from the environment starts to colonize our body. Just like humans colonize land that is ideal for their life.
The first microbiota that colonizes our body becomes the dominant microbiota, and once it settles in, it prevents other different bacterial species from settling.
Suppose that initial colonization is by probiotic bacteria like lactobacillus, bifidobacteria, or other probiotics. In that case, it is excellent because they’re beneficial for our health.
Unfortunately, it works the opposite way too. Once pathogens take over your gut, mouth, skin, and urogenital tract, which manifests as chronic inflammation, it’s hard to reverse it because those pathogens also have mechanisms to ensure that probiotic bacteria don’t stick.
That’s why probiotic supplementation seldom makes much difference with those chronic conditions, and sometimes it can even cause adverse reactions like bloating, cramps, etc.
Often the only solution in such advanced chronic dysbiosis is microbiome transplantation combined with a specific dietary protocol for microbiome diversity and balance restoration.
4. Microbiota creates a specific chemical environment that repels pathogens.
A healthy microbiome creates immunity, while a disrupted microbiome weakens immunity. It is due to the chemical environment that microbiota creates. Each bacteria produces different metabolites and peptides, creating different PH and environments around it.
For example, studies showed that women with a healthy vaginal microbiome are more immune to viruses such as HPV, HIV, and other pathogens. It is because healthy vaginal microbiota is composed mainly of Lactobacillus bacterial species (about 70% of the microbiome), and these bacteria create a more acidic environment that is unsuitable for other pathogens. On top of lactic acid production, these probiotic bacteria produce antibacterial peptides (literally antibiotics that work against other bacteria). That creates a healthy environment where probiotic bacteria thrive, and pathogens can’t survive.
On the other hand, women with a disrupted vaginal microbiome and bacterial vaginosis (BV) are more prone to getting HPV, HIV, Herpes, and other pathogens when they come to contact with them during sexual intercourse. Due to dysbiosis, the vaginal environment provides more optimal conditions for those pathogens and less optimal for probiotic bacteria.
Multiple factors, such as diet, antibiotics, or other prescription drugs, and frequent exposure to pathogens, impact the microbiome on all body sites.
A research study showed that people whose gut was colonized by the Bacillus species (probiotics) did not have Staphylococcus aureus (pathogen) in their gut. And those that had Staphylococcus aureus did not have Bacillus species in their intestines.
This colonization resistance is due to Bacillus species secreting a class of lipopeptides that inhibits S. Aureus quorum-sensing signaling, which is crucial for S. aureus intestinal colonization.
5. Microbiota metabolizes food into other digestible components.
One of the essential functions of the gut microbiome is the metabolism of fiber and other food components and the production of metabolites. Bacteria produce enzymes that break down fiber and other indigestible food components, turning them into fatty acids and other metabolites that can be absorbed through the intestinal wall into the bloodstream and used by the body.
Bacteria produce a range of amino acids, vitamins, hormones, neurotransmitters, and other metabolites that are crucial for the optimal functioning of the human body and immune system.
Without bacteria, our body would be deficient in those nutrients, vitamins, and hormones. Living without those crucial components can disrupt our physical and mental health.
Scientists consider the gut microbiome to be a virtual organ of the human body because of these metabolic functions. But as with all organs, it can be transplanted. If you feel that your microbiome is in dysbiosis or dysfunctional, you should consider transplantation to regain the crucial functions for your health.
6. Your microbiome influences your food and lifestyle choices.
Last but not least, your microbiome directly impacts your mood, food preferences, and other lifestyle choices.
More than 100 trillion bacteria are in our digestive tract, producing thousands of different chemicals that directly impact our physical and mental health. Dysbiosis in the microbiome can easily cause an imbalance in neurotransmitters and other hormones such as serotonin or oxytocin, which usually manifests as low mood, depression, anxiety, and even autism and other physical symptoms.
Those biological changes in your body and brain can influence your food and other lifestyle choices. For example, it can make you crave sugar, junk food, alcohol, or drugs and even make you socially isolated. Those choices can subsequently lead to other bad choices, further worsening the condition, and over time such lifestyle changes can lead to weakened immunity and illness.
So there you have it. Six ways your microbiome directly or indirectly impacts your immunity, health, and wellbeing. Do you feel like your microbiome is in good condition, or is it giving you signals that it needs an upgrade? If you’re unsure, you can read about the ten signs of gut dysbiosis or consider MyNewMicrobiome protocol to upgrade your microbiome.