10 Facts about the Human Microbiome

Human Microbiome: Why it is important for our health

Research in the microbiome is yielding fascinating results and has the potential to lead to a next generation of transformational self-care treatments for people around the world. But what exactly is the human microbiome, which role does it play for our health and why is it referred to as our “second self”? We have collected some interesting facts for you.


June 27th is declared World Microbiome Day celebrating the diversity of the human microbiome.
Fact 1: The Microbiome is your second self

The human microbiome is an intricate community of microorganisms that live on and inside of our body.1 Each of us has a very individual one. Even identical twins, who share 99.5% of their genes, only share about 20% of their gut microbiomes.2 That’s why it is known as our “second self” due to several factors, such as its abundance: our microbiota take up the majority of the approximately 100 trillion cells that make up our body. These cells consist of bacteria, fungi, viruses, and other microorganisms. The relationship between us and our microbiome is so intertwined that one can think of the human body as one superorganism made of human and microbial cells.


Fact 2: Your Microbiome is a large invisible organ, and natural shield

Like our other organs, our microbiome performs specific functions such as digestion, maintaining a healthy skin balance, education of our immune system, and synthesis of certain vitamins. In fact, if our bacteria and other microbes were put on a scale, they would weigh about 2 kg (about 4.4 lb.). This would make it our second largest organ after our skin. Our microbiome is also a natural shield against a variety of illnesses. When in balance, it helps modulate our metabolism, supports our immune system, and contributes to our skin as well as oral health.


Fact 3: It’s a microbial fingerprint

The microbes that compose our microbiome are primarily concentrated in seven regions of the body: our stomach, nose, mouth, lungs, skin, colon, and sexual organs – and we each have a unique composition of microbes in each region. As an example, our oral microbiome is primarily composed of Streptococcus, however, the proportion of this bacteria is specific to each of us. Also, certain bacteria are commonly present in one part of our body, but seldom found in others. For instance, Propionibacterium dominate our skin microbiome, yet they are of very low existence in our gut microbiome.


The Human Microbiome in our body


Fact 4: We may start to develop our Microbiome before we are born

Experts have long questioned whether we acquire our microbiome at birth, or if it is developed in the womb; a recent study may help answer that question.3  Researchers found a bacterial microbiome signature in fetuses as young as 11 weeks post-conception. It is understood that exposure to certain environmental stimuli can shape our microbiome in our infancy, and thereby induce resistance to certain allergies. As an example, human breast milk helps further promote the microbial diversity of a baby’s gut microbiome and your environment shapes the composition of your skin microbiome.4

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    Fact 5: It is constantly evolving

    Composition and diversity of our microbiome change remarkably as we age. The diversity of our gut microbiome, for example, increases during our first two to three years of life and then stabilizes. This diversity begins to decrease in our older years. Studies have confirmed that the composition of our skin microbiome also varies as we age.5 Scientists are studying these changes in search of potential treatments to help aging skin.


    Fact 6: Our Microbiome can be influenced by our diet, and other external factors

    What we eat can directly impact the composition and abundance of our gut microbiome. Interestingly, two people may eat the same foods and experience different changes to their microbiome – this underscores the highly personal nature of the microbes that inhabit our bodies. A study published last year6 found that swimming in ocean water significantly alters our skin microbiome, and these changes persisted for 24 hours or more.


    Fact 7: It can affect (and be affected by) seemingly unrelated organs

    The ancient physician Hippocrates famously stated that, “All disease begins in the gut”, and it appears he may have been at least partially correct. Current research indicates that our gut microbiome may play a role in brain processes that affect our mental health, cancer, cardiovascular health, and other diseases. It is also believed that stress and other external stimuli can adversely affect its composition and function. The gut microbiome is even involved in the physiological function of our immune system: Our gut is the home of about 70% of our immune cells and the microbiome plays an important role in educating our immune system.7


    Fact 8: Microbial diversity is key

    It is fair to say that there are good and bad bacteria. However, in terms of our microbiome it is important to have the good ones predominate. Studies have not yet established a profile of the ideal, healthy microbiome. However, the loss of microbial diversity, specifically in our gut microbiome, is associated with the rise in many diseases such as asthma, obesity, diabetes and atopic dermatitis.8


    Fact 9: Products and treatments claiming to benefit our microbiome are on the rise

    More than 100 products claiming to benefit our microbiome were launched last year, and more are on the way. Generally, these products fall into one of the following categories


    1. Microbiome friendly: products that ensure the microbiome is not harmed 
    2. Prebiotics: nutrients that are supposed to feed the “good” bacteria to boost the microbiome 
    3. Probiotics: live microorganisms thought to provide a health benefit 
    4. Postbiotics: substances produced by bacteria that mimic their positive effects


    Additionally, several companies now market tests that outline the composition of the gut microbiome, with the promise of providing personalized dietary recommendations to promote weight loss and promote health. Make sure to research the clinical evidence that support these claims and make educated decisions.


    Fact 10: Bayer Consumer Health is working to develop new, trusted solutions that target the microbiome

    Bayer Consumer Health is focused on the human microbiome, and firmly believes that this pathway can lead to transformative self-care solutions for consumers around the world. We are augmenting our own internal scientific capabilities through agreements with both academic and industry collaborators. Earlier this year we announced our partnership with the U.S. firm Azitra, which seeks to leverage skin friendly bacteria to help individuals with adverse skin conditions and diseases. As we are relentlessly pursuing new, transformative solutions in this space, we continually seek to work with new partners – universities, startups and other likeminded companies. Interested? Come and talk to us!

    Research into the human microbiome has grown significantly in recent years as scientists have better understood its important role in maintaining health. We are at a tipping point as our understanding of the human microbiome is poised to become the platform for new treatments that can change the paradigm of certain illnesses, as well as promoting better health and wellness. We at Bayer already have many trusted global brands such as Iberogast® in digestive health and Bepanthen, where the SensiDaily product contains a prebiotic, and we are constantly working to develop the next-generation of science-based consumer health solutions.
    David Evendon-Challis
    Head of R&D Bayer Consumer Health