What Is The Human Microbiome?

The human body is a collection of organs, tissues, and systems that keep you functioning. This collection makes up the symbiotic function of life – meaning when one system isn’t working well, the others are negatively affected. In some cases, they’ll actually follow suit. This is why it’s essential to manage your health as a whole as opposed to one particular system at a time. One of the parts of the body that plays a significant role in overall health is the microbiome. But what is the human microbiome, and how does it affect your overall health?

What is the human microbiome?

The microbiome is a collection of microorganisms living in the body and skin. Specifically, these microbiomes consist of microbial genomes that help make up a person’s genetics. A diverse group of bacteria, archaea, fungi, non-living viruses, and protozoans makes up the microbiome. However, bacteria reign supreme – they can be found in high numbers: between 75 trillion to 200 trillion, to be exact.

To put that into perspective, the human body comprises only 50 to 100 trillion cells. That means there are far more bacteria species living in the microbiome than there are cells in the human body. Because of this collection of diverse microbial populations, it’s been said that the human body is actually a superorganism – a blended organism made up of cells, genes, and microbials. Among the microbiota living in the human body as part of the microbiome are roughly 900 to 1000 different species.

Each organism in the microbiome is specific as to what place in the body it calls home. For example, the species of bacteria that live on the left hand may differ slightly from those that live on the right hand. Aside from the skin, the human gut is the area of the body that houses a diverse collection of these microorganisms.

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What are the main roles of the gut microbiome?

The gut microbiome has a hand in several different bodily processes. Because of this, it plays a vital role in how healthy the body is overall. The primary functions of the gut microbiome include:

Nutrient metabolism

The body uses the gut microbiome to break down food for nutrients. Since the microbiota in the gut are living organisms, they too need to feed on something. Typically, their diet is focused heavily on carbohydrates. When these organisms devour carbohydrates, the process helps to synthesize specific nutrients so the body can use them where necessary. The microorganisms also help with the transfer of certain nutrients.

Xenobiotic and drug metabolism

The digestion and absorption of foreign substances (xenobiotics) and drugs/medications rely heavily on the microbiota in the gut. Many people need regular medications to treat various chronic ailments. When the microbiome is working on making the benefits of these drugs readily available, people can keep their conditions managed effectively.

Antimicrobial protection

It may seem counterintuitive, but the bacteria and other organisms in the gut actually protect the human body from other, more harmful microorganisms. They do so by inducing changes in the immune system so that any bacteria that aren’t serving the body can be eliminated before they become overgrown and cause a problem.


Building on our last point: the immune system relies heavily on healthy gut bacteria and organisms. The microorganisms that make up the gut microbiome help to control, regulate, and modulate both the innate and adaptive immune systems. By doing so, they help to prime the system for action if illness or disease happens to develop within the human body.

Ensuring the integrity of the gut barrier and structure of the GI tract

The gut barrier and GI tract are vital for overall health. When digestion is hindered by disease, inflammation, or illness, it can lead to chronic health disorders. The microorganisms within the human body work to ensure that these areas are maintained and taken care of, and that the structure of the digestive system stays intact.

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Why is the human microbiome important?

The various functions of the microbiome keep specific processes and systems working as they should. But how does the microbiome impact human health? Well, the microbiome’s importance effectively lies in how those processes affect overall wellness. For example, nutrient digestion is vital so that deficiencies don’t occur. When they do, they can cause various ailments and even chronic diseases.

Other reasons why a healthy microbiome is essential include:

  • Weight control and management
  • Decreasing the risk of developing intestinal diseases, including inflammatory bowel disease and irritable bowel syndrome
  • Helping to promote higher levels of good cholesterol and lower levels of bad cholesterol, therefore increasing heart health
  • Controlling blood sugar levels and reducing the risk of diabetes
  • Helping produce chemical messengers known as neurotransmitters used by the brain to ensure overall mental and cognitive health

If gut bacteria become imbalanced, a person will enter a state of dysbiosis. When that happens, they risk experiencing all sorts of diseases, including metabolic syndrome, obesity, and atopic skin diseases. But with the proper balance of gut bacteria, a person can decrease their chances of developing disease simply because a happy gut ensures a healthy body.

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