By now you’ve probably heard the term microbiome and know it has something to do with human health? But what is the microbiome, exactly? Why is it getting so much attention? And, what can we learn from it?
In this four part series on the Microbiome, we will unpack these questions and more, helping you to take charge of your health and well-being.
Hope you follow along!
MICROBIOME 101: A Primer
Did you know that at this very minute you are hosting an invisible army of 39 trillion micro-organisms in and on our body. Yep, 39 trillion - that’s 10 times the number of stars in our galaxy! The key players in this microbial arsenal are bacteria, but right alongside them are archaea, eukaryotes, and even viruses, each one doing its part to help you to maintain homeostasis and stay healthy. This bustling community of microscopic bugs, collectively known as your microbiota, reside mostly in the gastrointestinal tract, but they also live in the nasal passages, lungs, vaginal opening, and on your skin. (1).
All told, your microbiota weighs in at 3-5 pounds and accounts for more than half the number of cells in your body, meaning you have more microbial cells than human cells! And, if that fact didn’t get your attention, this one will: In terms of our genetic code, we are only 1% human: While the human genome - the complete set of genetic instructions for a human being - consists of around 23,000 genes, our microbiome encodes over 3 million genes that produce thousands of metabolites essential to human health and homeostasis.(1) In fact, studies show that the microbes living in and on our body actually provide us with genetic variation and gene functions that our own human cells are not evolved to do! (2) In short, we are in a symbiotic relationship with our microbiota: When we take care of them and give them the proper food and shelter, they take care of us. When we don’t, we put these communities and ourselves at risk for dysbiosis and disease. (3)
Are we Human?
In the past we would have thought of ourselves as autonomous, unitary individuals, but now one could argue that we are heliobionts or superorganisms, made-up of the host (in this case, us) and the 39 trillion bugs that colonize our body and perform functions essential for our survival. (4) The interaction between our human and non-human elements is what actually makes us who we are. (5)
What is the Microbiome?
The Microbiome is the total genetic material of the microorganisms within the human body. (6) When talking about the microbiome, it’s important to remember that each area of the human body houses its own unique population of microbial residents that are best suited to live there. The composition of microbes and the kinds of genes they have are habitat-specific, for example you will find different species of microbes lining your intestinal wall than you will find sitting on your arm. (7)
What does our Microbiota Do?
Beneficial microorganisms live in harmony with us and perform functions vital for human health and survival. Our microbiota plays an integral role in digestion, nutrient extraction and elimination, as well as immune function, metabolism, brain health, mood regulation, skin and wound healing and weight management. The better question is what doesn’t our microbiota do!
How do we get our Microbiota?
Your microbiome begins to develop even before you are born. We are first exposed to microorganisms in the womb, as bacteria from the mother makes its way through to the uterus to the developing fetus. Colonization continues as the baby moves through the birth canal, enjoys some skin to skin contact with its mother and takes its first sip of bacteria rich breast milk. The mother’s microbiome largely determines which species of microorganisms the baby will first encounter in the early stages of building its own microbiome. (8) As the baby grows, diet and environmental factors, such as exposure to pets, home environment and medications, come into play and help shape the developing microbiome. By the time a child reaches 3 years of age, they will have established a mostly stable, adult-like microbiome, but, in later life, there is a dip in gut microbiota diversity that is tied to age related disease and frailty(9).
Artwork by Rogan Brown
Big Takeaway:
The microbiome is a living, breathing life force that, though relatively stable from age 3, is mutable and responsive to our lifestyle choices. When we eat well, get enough sleep, manage stress, and regularly move our bodies, we take an active role in shaping and maintaining our gut microbiota throughout our lifetime, empowering us to live a long, healthy, beautiful life. (10)
In the coming weeks, we will explore how you can use different lifestyle interventions to optimize your microbiota to promote long term health and well-being.
Next up: How Food, particularly fiber affects microbiome health.
