The gut gets the majority of the attention when we talk about the microbiome (even though your mouth has a vast microbiome as well!). The digestive system is home to trillions of organisms that can affect the body, but it is definitely not the only place these bacteria exist.
Microbiome has become a household word! It refers to the mix of bacteria, yeasts, and parasites that live on your skin, in your nose and trachea, and in your gut from your mouth to your anus. The mix of those bacteria, yeasts, and parasites is closely linked to weight, mental health, autoimmune health, blood pressure, diabetes, heart disease, and even cancer.
Our bodies are ecosystems that harbor a microbial universe. Each of us has approximately 10 trillion human cells, 100 trillion bacteria, yeasts, and single cell protozoa (representing thousands of different species), and 1,000 trillion viruses in and on our bodies.
Scientists now consider the microbiome an important organ that helps us maintain the necessary metabolism to keep the chemistry of life running as effectively as possible. If properly tended, our microbiome can keep us lean, joyful, and pain free. But when our metabolism malfunctions, too many free radicals are made, inflammation increases, and our chemistry falters, leading to ill health.
Recent research shows that we may have an equally diverse and important microbiome in other parts of the body such as in the mouth and on the skin.
A microbiome is simply the collection of microorganisms in a particular place. The gut microbiome is the entire collection of microorganisms in the gut, and similarly, the skin micrombiome is simply all of the organisms present on the skin.
The term “microbiota” is also used to describe these organisms and specifically means: “the ecological community of commensal, symbiotic and pathogenic microorganisms that literally share our body space.”
Because research is proving the importance of the gut microbiome, many of us now understand how important it is to consume probiotic rich foods, and why overuse of antibacterial soaps is a bad idea for gut health. It turns out that these same factors also affect the microbiota on our skin and protecting it may be just as important!
In fact, most skin problems (from acne to eczema) likely affect the skin microbiome and may be a result of changes to this ecosystem due to modern lifestyle.
Our modern lifestyle assaults our gut microbiome through antibiotic overuse, consumption of foods that disrupt gut flora, and overuse of antibacterial products. These same factors can alter the bacterial balance on the skin and may be even more damaging!
The skin is under constant assault from environmental agents, harsh cleansers and soaps, deodorants, and even medications and cosmetics. Our obsession with cleanliness may be doing more harm than good for microbiota balance on the skin.
Like the gut, the skin is home to over a trillion organisms at any given time, including thousands of species of bacteria as well as viruses and fungi. (source) These all serve a purpose and are important for proper balance. Like the gut, when the balance is altered, it can create problems.
Skin was once thought to be just a physical barrier from the outside world, though the existence of skin-associated lymphoid tissue shows that it is much, much more. I find these lymphocytes absolutely fascinating. Here’s why:
Researchers estimate that these lymphocytes exist on the skin in a 1:1 ratio with bacteria. The theory is that these immune cells are capable of sensing and dealing with a great deal of bacteria on their own. They also communicate with lymph nodes within the body. These lymph nodes carry immune signals to the rest of the immune system and help determine the body’s appropriate response. (source)
In short: your skin contains trillions of lymphocytes that are like soldiers protecting your body’s perimeter and radioing in information about approaching attacks to the main base (your immune system).
A healthy skin microbiome appears to begin during and shortly after birth with a flurry of immune activity. Unfortunately, many of the modern practices surrounding birth may have a dramatic and unfortunate impact on gut bacteria.
Researchers at the University of California San Fransisco found that an important part of the skin microbiome is established within days of birth. Mainly, that within days of birth, there is a large amount of T-cell activity that creates tolerance in the immune system to the bacteria on the skin. This is a critical factor in the immune system knowing not to attack the normal and healthy bacteria on the skin.
Unfortunately, the wide use of antibiotics for mom during labor (and for mom and baby after birth) may have some big unintended consequences.
“One major clinical implication of this study is giving antibiotics to a child in early neonatal life is likely a disservice because this will limit the amount and type of bacteria that is seen by the adaptive immune system and this could be linked to the development of autoimmune, inflammatory skin diseases later in life,” said Rosenblum.
Logically, this could be part of the reason we are seeing a rise in skin related disorders and why the research in the movie Microbirth is even more critical! The research indicates that if this window is missed, it is difficult or impossible to recreate as an adult. (This is also a good reason to hold off on a first bath for the first few days of a baby’s life!)
Here’s the full text of the study if you want to read it.
No part of the body’s microbiome exists in a vacuum, which is why it is important to continue to understand the different parts of the biome and how they interact. As the study above indicated, the skin is home to trillions on lymphocytes that interact with the rest of the immune system via lymph nodes. Just like the bacterial organisms in the gut, they comprise a valuable part of the immune system.
This also gives reason to rethink the overuse of antibacterial and antimicrobial soaps on the skin.
I’ve posted before about the importance of “good clean dirt” and how most of us aren’t getting enough of it. This new evidence suggests that our obsession with being “clean” may come at a big price for our microbiome.
Dr. Kara Fitzgerald explains:
A robust skin microbiome protects against infection or dysbiosis in much the same way a good gut microbiome does, by colonization resistance (i.e. crowding out overgrowth of pathogenic organisms) and by maintaining relatively acidic environment (pH is around 5.0), which inhibits growth of pathogens. Staphylococcus epidermidis, a major commensal bacterium, produces phenol-soluble modulins that inhibit pathogens such as S. aureus and Group A Streptococcus. Commensals can also inhibit inflammation through cross-talk via Toll-like receptors 2 and 3, and stimulate production of antimicrobial peptides such as cathelicidin, which can kill bacteria, fungi and viruses.
The microbiome aids in wound healing, limits exposure to allergens and UV radiation, minimizes oxidative damage and helps to keep the skin barrier intact and well-hydrated.
Rather than thinking of the skin as a complex microbiome to be nurtured and protected, we often think of it as a static surface that needs to be clean. Over the long term, this may have a negative effect on skin health and even the immune system!
While the bad news is that we don’t seem to have a good way to encourage proper immune system and skin bacteria interaction after the important newborn window, there are some things we can do to encourage a healthy skin biome in older children and adults.
It may sound crazy, but in today’s world, we just don’t get enough dirt… or soil based organisms to be precise.
Think about this… for most of human history, we worked outside or interacted with the outdoor world in some way each day. Food came from the ground and while it may have been rinsed, it wasn’t “washed” and it certainly wasn’t irradiated like many foods are today. Through these interactions with the soil, we came in contact with soil based organisms (SBOs) that are natural strains of probiotics found in the gut and on the skin.
Now, we are deficient in dirt and don’t come in contact with these beneficial organisms enough. Heck, we don’t come in contact with anything dirty regularly.
Sure, we could take a probiotic supplement, but most of them don’t have the same strains of bacteria. Unless they are SBOs (also known as spore-forming bacteria) they may not survive the harsh environment in the stomach and upper digestive system to get to the small intestine.