14 Amazing Facts About the Human Microbiome & Your Gut

Amazing facts about the human microbiome

Did you know that the word “microbiome” comes from ecology? Are you aware that your microbiome is totally unique and can serve as your microbial fingerprint? Did you know that your microbiome started to develop even before you were born? And how about the fact that about half of the cells in your body are microbial? Read on to uncover more amazing and science-backed facts about the human microbiome!

Disclaimer: This page is for informational purposes only. Please discuss your health concerns with your care provider and consult them before taking any supplements to avoid disease and drug interactions.

Shop Our Probiotics

Amazing Facts about the Human Microbiome Infographic

Amazing Facts About the Human Microbiome Infographic

1. What is a Microbiome?

The concept of the microbiome has its roots in ecology. 

The word “microbiome” was allegedly popularized by Nobel Laureate and microbiologist, Joshua Lederberg, in 2001. But unlike many sources claim, Lederberg didn’t coin the term. 

The word “microbiome” was first used in the 80s. 

In 1986, Scientists Linda R. Hegstrand and Roberta Jean Hine published a groundbreaking animal study proving that the microbiome can influence brain chemistry (Prescott, 2017). 

Around the same time, a group of ecological scientists (Whipps and colleagues) defined the microbiome as a community of microbes and their activities within a specific environment. This definition was later modified to include the human body as a host (Prescott, 2017). 

We can look at the whole world through a lens of interacting microbiomes. Microbiomes are in the soil, plants, animals, and within the human body. 

Read Next:

2. Definition of the Human Microbiome (& Its Locations)

Scientists sometimes use the word “microbiome” interchangeably with the word “microbiota”.

The human microbiome or microbiota is defined as a set of organisms inhabiting and interacting with the human body (Ogunrinola et al., 2020). 

The genetic code of microbes living in a certain part of the human body makes up its microbiome. We may host the following microbiomes in our body (Ogunrinola et al., 2020):

  • The skin microbiome
  • The gut microbiome (both in the gut and along its lining)
  • The oral microbiome
  • The respiratory microbiome
  • The urogenital microbiome (including the vaginal and urinary microbiomes)
  • The breast gland microbiome (including the breastmilk microbiome)

3. Your Gut Microbiome Is Not Just Bacteria

We commonly think of the gut microbiome as being made of just our “good” bacteria. But it’s much more than that. 

Aside from bacteria, the gut microbiome also contains fungi, viruses, and methanogens. Methanogens are an ancient type of organism that can produce the gas methane through fermentation (Djemai et al., 2022). 

All organisms that make up your can microbiome can be either beneficial or harmful. This depends on their type and diversity. When in balance, they help promote optimal health. When out of balance, they can contribute to disease (Chaudhary et al., 2018; Lecuit & Eloit, 2017). 

4. You Are About As Much Microbe as You Are Human

When we ask what it is to be human, we should also ask what the human microbiome is!

The human microbiome consists of 10-100 trillion symbiotic microbial cells, most of which are bacteria in the gut. Scientists even call the microbiome our “second genome.”

You might hear that we have 10 times more microbial cells than the cells of our own body. But this isn’t correct! It dates back to a problematic 1972 article that has since been debunked (Gilbert et al., 2018). 

Scientists analyzed up-to-date information to reveal that we seem to be at least as much microbial as we are human! (Sender et al., 2016)

The number of microbe cells in our body is similar to the number of human cells (about a 1:1 to 1.3:1 ratio). Still, microbes give us only about 0.4 lbs (0.2 kg) body weight. This doesn’t take away from their importance, though! (Sender et al., 2016)

According to a rough analysis, about 1000 bacterial species are living in our gut. Each species has about 2000 genes. This brings us to 2 million microbial genes—that’s 100 times more genes than our own genome of around 20,000 genes! (Gilbert et al., 2018

Large research initiatives like MetaHIT87 and the Human Microbiome Project (HMP) list similar numbers. The HMP is an ongoing American initiative seeking to create a database of human microbiome samples and understand their role in health and disease. 

5. Your Microbiome Is Your Microbial Fingerprint

Your microbiome makes you unique. No two people have the same microbiome. 

All human beings are 99.9% identical to each other at the human DNA level. But when we look at microbiome genes, people can differ by 80-90%! (Collins & Mansoura, 2001

Even identical twins who share the same DNA can have totally different microbiomes. Recent estimates say that only up to 10% of microbial diversity is linked to heritable factors (Vilchez-Vargas et al., 2022). 

According to new research, our unique microbiome profiles may even be used to identify us, acting as a microbial fingerprinting system. A person’s microbial fingerprint may help physicians understand their health status and better tailor treatment in the future (Vamanu et al., 2016; Tomasello et al., 2017). 

Interestingly, in one study using microbial fingerprinting, 80% of people remained identifiable within a year of having their gut microbiome sampled (Franzosa et al., 2015).

6. Your Microbiome Forms Before You Are Born

Doctors used to think that the womb is sterile, but we now know that it normally houses microbes. An even bigger discovery is that fetuses seem to start developing their microbiome during the first months in utero!

A recent study reveals that fetuses as young as 11 weeks in the womb have a bacterial microbiome in their lungs (Alam et al., 2020).

Even the placenta has its own microbiome, which helps support a healthy pregnancy (Zakis et al., 2022). 

We also know that taking probiotics during pregnancy can support the microbiome of the baby after birth and lower the risk of allergies (Colquitt et al., 2022). 

Therefore, your microbiome dates back to when you were in your mother’s belly!

Read Next:

7. How You Are Born Affects Your Microbiome 

Babies pick up beneficial bacteria when passing through the birth canal. This is why both the vaginal and gut microbiomes are so important during pregnancy—they shape the baby’s microbiome at birth (Corpella, 2021). 

Babies born via a C-section miss out on this benefit, which has led to the practice of microbiome seeding in some hospitals. Microbiome seeding involves transferring the mother’s vaginal microbes to the baby after surgical birth (Kelly et al., 2021). 

Antibiotics can also disrupt a baby’s microbiome. Dr. Martin J. Blaser, the author of Missing Microbes, writes: “Exposure to antibiotics early in life causes microbial perturbations at a crucial time, just when organs and systems are developing.”

This can be remediated with breastfeeding and probiotics (Corpella, 2021). 

8. Your Early Childhood Shapes Your Microbiome

Human breast milk helps further promote the microbial diversity of a baby’s gut microbiome

Breast milk is rich in probiotics, and its composition is directly impacted by the mother’s diet and lifestyle. A mother’s skin and oral microbiome, as well as the environment and people the baby is exposed to, also shape the baby’s microbiome during infancy (Boudry et al., 2021; Sun et al., 2019). 

The microbiome continues to develop and stabilize during the first years of life. Nutrition, breastfeeding practices, exposure to medications and chemicals, and the environment all play important roles in forming a strong microbiome in children (Ronan et al., 2021). 

Read Next:

9. Your Microbiome is Alive and Developing

Although the adult microbiome is more stable than a child’s, it’s still alive and developing. 

Your gut microbiome is like a moving puzzle that adapts to your lifestyle and surroundings every day. Both healthy and dysbiotic states can co-exist, but one will be more dominant (Levy et al., 2017). 

If you feed your system healthy factors, a shift toward gut microbiome health (symbiosis) starts to happen. If you add unhealthy factors in, disease-forming tendencies (dysbiosis) start grouping together.

Read Next:

10. Your Gut Microbiome Makes Vitamins & Neurotransmitters

Your gut microbiome directly affects your nutrient status. The trillions of microbes that live in your gut are working hard to extract, produce and absorb vitamins, minerals, and other nutrients from food (Carding et al., 2015). 

Your gut microbiome is also involved in helping to produce and break down neurotransmitters, chemical messengers that affect your mood and emotions. In fact, 95% of your total body serotonin—also known as the “happiness neurotransmitter”—is produced in your gut! (Dicks, 2022; Appleton, 2018)

Read Next:

11. Your Diet Can Make or Break Your Microbiome

Eating a healthy diet is the single most effective step you can take to support your microbiome. A diet high in prebiotic fiber and fermented probiotic-rich foods helps to balance your gut microbiome and soothe your gut (Dahiya & Nigam, 2022). 

A microbiome-friendly diet is high in vegetables, fruits, legumes, fermented foods, and healthy fats. The focus should be on organic, whole foods. 

You should avoid processed food, sugar, and diets low in fiber that disrupt the microbiome (Gagliardi et al., 2018; Rinninela et al., 2019).

12. Your Lifestyle Shapes Your Microbiome

According to studies, stress and depression can disrupt the gut microbiome through high levels of stress hormones and inflammation (Madison & Kiecolt-Glaser, 2019). 

Reducing stress, losing extra weight, staying active, and making sure you’re getting enough sleep and natural sunlight helps to reshape your gut microbiome into good health (Conlon & Bird, 2015).  

13. Your Gut Microbiome Affects Your Cholesterol Levels & Heart Health

Your gut microbiome plays a role in your metabolism of cholesterol and fats. 

If your gut microbiome is out of balance, you may not be able to break down and remove excess cholesterol, fats, plant sterols, and bile acids. This is in line with the research: there’s a link between gut microbiome dysbiosis and high cholesterol (Jia et al., 2021).

Therapies targeting the gut microbiome hold potential for people with high cholesterol and heart disease. Prebiotics, probiotics, fecal microbiota transplantation, and herbal remedies are being explored (Jia et al., 2021).

  1. Reuteri NCIMB 30242, our probiotic at Microbiome Plus+, is a clinically tested strain that helps support healthy cholesterol levels. In clinical trials, L. Reuteri NCIMB 30242 reduced LDL and total cholesterol levels compared to the placebo (Jones et al., 2012; Jones et al., 2013). 

Access our clinical studies page here to learn more

14. Your Immune System Is in Your Gut!

Did you know that 70% of your immune system is in your gut?

Your gut microbiome plays a major role in your immune health. It strengthens immune defense against any foreign invaders and balances immune cells to help prevent autoimmune and allergic reactions (Carding et al., 2015). 

Certain probiotic species like L. reuteri are even antimicrobial and may stop viruses and bacteria from spreading in the body (Mu et al., 2018). 

  1. reuteri NCIMB 30242 also increased vitamin D3 blood levels by 25.5% in a Canadian clinical trial of 123 people. Vitamin D boosts the immune system, protects against infections, and improves respiratory health and lung function (Prietl et al., 2013). 

Read Next:

Microbiome Plus+ is dedicated to your microbiome health

Microbiome Plus+ is dedicated to the science of the microbiome and to providing advanced digestive health supplements that are backed by science.

Browse our shop to learn about our prebiotics, probiotics, digestive enzymes, and our other gut-supportive supplements. 

Ana Aleksic, MSc Pharm

Ana is an integrative pharmacist and scientist with many years of medical writing, clinical research, and health advising experience. She loves communicating science and empowering people to achieve their optimal health. Ana has edited 800+ and written 150+ posts, some of which reached over 1 million people. Her specialties are natural remedies, women’s health, and mental health. She is also a birth doula and a strong advocate of bridging scientific knowledge with holistic medicine.