Thinking of microorganisms, you may mostly remember bacteria and fungi responsible for diseases or mildewing of food. However, many more microbes are responsible for your homeostasis than diseases. Let’s take a look at the micro-world inside of us.

What Is The Human Microbiome?

The shortest answer to that question is the genetic material of all microbes inside a human body. That includes bacteria, fungi, protists, and viruses (though they are not living organisms). They are tiny but don’t underestimate their role. There are over 100 trillion microbes in your body right this second. Most of them live in your guts, helping digest your meals and provide the necessary nutrients. They also outnumber your cells one to ten. Moreover, the number of genes of all microbes in the human body outnumbers our genes 200 times, and our microbiome weighs about 2.25 kg (5 pounds).

The cells in the microbiome outnumber human cells 1:10!
The cells in the microbiome outnumber human cells 1:10!
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Major Bacteria Functions

The bacteria are everywhere inside our bodies. Lactobacillus and E.coli (which also has a pathogenic version) populate the digestive system. Archea and bacteria also produce vitamin B12 responsible for the synthesis of myelin, which is necessary for nervous system functioning. Moreover, various bacteria synthesize two more B vitamins- thiamin (B2) and riboflavin (B2). Vitamin K, needed for blood coagulation, is produced by microorganisms in the human intestine. Not only do they perform their tasks but also guard against other microorganisms that may be dangerous for our health.

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E.coli is one of many microorganisms in the human intestine
E.coli is one of many microorganisms in the human intestine.
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Major Fungi and Other Organisms

Fungi are natural providers of antibiotics, which means they defend us from bacteria that might be pathogenic. That way, they also protect other microorganisms in our biome and keep it stable. Yeast is present in our digestive system and skin, where some species feed on skin-produced oils. Among different species, we can find some symbiotic protists and even micro-animals in our bodies, though they are excluded from the definition of the microbiome. Humans also have their virome, which is the collection of viruses. They appear in our lungs, blood, oral cavity, and the digestive system.

Microbiome and Health

As we established, the human microbiome plays a vital role in the functioning of our organisms. It is logical to assume that its dysfunction can cause malfunction of the entire system and, therefore, human diseases. We can link autoimmune diseases in this case. Pathogenic microbes can accumulate, changing the genetic expression and metabolic processes when the ‘correct’ microbiome is compromised. Autoimmune diseases, like diabetes, arthritis, fibrymolangia, may be passed from generation to generation not by genes but by microbiomic heritage. Therefore studying and understanding our microbiome is essential in properly recognizing and curing some medical conditions.


Study of The Human Microbiome

No one noticed the microbiome until the 1990s. Today, after roughly 20 years of recognition, it keeps on amazing scientists. The Human Microbiome Project (HMP) was a 5-year international initiative, whose primary goal was to characterize the genomes of microorganisms in 300 healthy people in particular body organs. The project was sponsored by the National Human Genome Research Institute, part of the National Institutes of Health in the US. There are still many projects on exploring the human microbe, both as a part and independently from the HMP.

Further Questions

There are still many unknowns in the study of the human microbiome. We don’t know exactly how it establishes in our bodies and what factors change it over time. We might wonder how diet, lifestyle, and immunity impact the biome and how it impacts those factors and the host. There is also a question of how the microbiome interacts with host cells and if it can be used to cure diseases.

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