The relationship between the gut
microbiome and healthy skin
Clinical pharmacist and functional medicine practitioner, David Arthur, unpacks the mysteries of the microbial world.
This article was inspired by Alanna Collen’s book: ‘10% Human (How your Body’s Microbes Hold the Key to Health and Happiness)’.
In years gone the gut has received the majority of the attention when we talk about the microbiome. The digestive system is home to trillions of organisms that can affect the body, but it’s not the only place these bacteria exist.
But what exactly is the microbiome? It refers to a mix of bacteria, yeasts and parasites that live on your skin, in your nose, your trachea and in your gut, from your mouth all the way to your anus. The mix of those bacteria, yeasts and parasites is closely linked to your weight, mental health, acquiring auto-immune conditions, blood pressure, diabetes, heart disease and even cancer. This list can go on and on.
Our bodies are like ecosystems that house the microbial world. Each of us have approximately 10 trillion human cells, 100 trillion bacteria and yeasts, and 1,000 trillion viruses in and on our bodies.
Scientists now consider the microbiome an important organ on its own that helps us maintain the necessary metabolism to keep the chemistry of life running as effectively as possible. If properly attended to and looked after, 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, bad skin and risks of cardiovascular disease and hormonal imbalances.
Research now shows that there is a relationship between our gut microbiome and the microbiome on the skin.
What is the skin microbiome?
As mentioned above, 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 microbiome 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 the 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 to affect the skin microbiome may be as a result of changes to this ecosystem microbiota balance within our guts, due to the modern lifestyle.
Insults to the skin microbiota
Our modern lifestyle changes 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 the 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. These all serve a purpose and are important for a proper balance.
When does the skin microbiome start?
A healthy skin microbiome appears to begin during and shortly after birth with a flurry of immune activity. However, recent studies have shown that many of the modern practices surrounding birth may have a dramatic and unfortunate impact on gut bacteria.
Important research recently published at the University of California San Francisco found that an important part of the skin microbiome is established within days of birth, when there is a large amount of immune cell activity that creates tolerance 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 labour (and for mom and baby after birth) may have some big unintended consequences.
The study reads: “One major clinical implication of this study is that giving antibiotics to a child in early neonatal life 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.”
Logically, this could be part of the reason we are seeing a rise in skin related disorders and why 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!)
How the gut and skin microbiome interact
No part of the body’s microbiome exists in a vacuum. The skin is home to trillions of immune fighter cells 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 and question whether we are too clean.
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 colonisation resistance (i.e. crowding out overgrowth of pathogenic organisms) and by maintaining a relatively acidic environment (pH 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, minimises 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.
Don’t be afraid to get dirty
It may sound crazy, but in today’s world, we just don’t get enough dirt or soil based organisms.
For most of human history, we worked outside or interacted with the outdoor world in some way each day. Our 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 into contact with soil based organisms (SBOs) that are natural strains of probiotics found in the gut and on the skin.
It seems ridiculous that now we are deficient in dirt, we don’t come in contact with these beneficial organisms enough. Heck, we don’t come in contact with anything dirty regularly. Most probiotic supplements 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.
Use a skin probiotic
Many of us take probiotics but few of us have ever thought of using a skin probiotic. There are skin probiotic masks and skin creams that make the skin softer and not as oily.
I advocate avoiding antibacterial soaps and choosing biome friendly soap. Triclosan, one of the most-used antibacterial ingredients in soaps, was recently banned, but others are still used. Use natural soaps instead.
There are also soaps and shampoos that are designed to not interfere with the skin biome. These contain ammonia-oxidizing bacteria (AOB) that research suggests may help restore healthy skin bacteria.
How interesting is this provided one has a washing peg on one’s nose – there is evidence that sweat may contribute to healthy skin bacteria by serving as a pre-biotic (food for good bacteria).
So, what’s the bottom line? Our skin microbiome would love it if we could ditch harsh synthetic and antibacterial skin products and stick to natural products, simultaneously fixing up and respecting our gut microbiome by changing our diets and lifestyles accordingly.
David Arthur holds the following qualifications: Clinical Pharmacist – B.Pharm (Wits), MPS, ABAAHP Diplomate, Board Certified (American Board of Anti-Aging Health Practitioners), Faculty MMI/SA, and A4M. He practices at the Integrative Medical Centre, focusing on functional and regenerative medicine. A particular area of interest is the relationship between emotional and physical health.