As scientists learn more about the gut microbiome and the impact it has on our overall health, there is increasing interest in the skin microbiome and the role it has to play.
Medical professionals, dermatologists, and aesthetics clinicians are realizing that bacteria may have a role to play in the treatments they give and the products their patients use.
Dr. Gill Westgate, Hon Visiting Lecturer, Centre for Skin Sciences, University of Bradford, says studies have linked high microbiome diversity to healthy skin.
“Thus products that do not interfere with or alter the species diversity are good for the skin. In skin disorders, products that are proven to shift the microbiome from unhealthy to healthy are an important and growing category and can shift lower to high microbial diversity. However, many products may claim to be good for the microbiome but have little supporting evidence; microbiome-targeted claims are now a new field in claims regulation.”
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Unique to Individuals
The skin microbiome describes all the microbiota that live on and in our skin, she explains. These skin micro-organisms – some one billion per cm2 – have evolved with us and serve to protect us against invading pathogens.
“Many people are now aware of ‘good’ and ‘bad’ gut microflora and the same situation exists in the skin. The overriding role of the skin microbiome is to act as a shield to the entry of pathogens into the body. The skin microbiome is established at birth and changes as we age. There are hundreds of different microbial species living on our skin and the number and composition are variable across body sites.”
Factors such as moisture level (in the armpit, groin, and flexural sites), sebum levels (in the face and scalp), and skin dryness (in the outer arm and lower leg) influence the skin microbiome composition, she says.
“One of the most interesting observations about the skin microbiome is that it is unique to each person and in healthy skin, it is said to be in balance.”
Gentler Products and Treatments
Current understanding of how to manipulate the skin microbiome using treatments and products is poor but of high interest says Dr. Westgate.
“Much is known about how skin and hair cleansers work. Now the move to milder formulations and bio-based surfactant ingredients is a strong trend. Milder cleansers are less damaging to the skin barrier, which, if compromised, can lead to a change in the microbiome composition and unhealthy skin. Younger and older skin has less resilience to skin damage and is more vulnerable, thus anything that increases skin resilience to dryness and damage will be helpful.”
Current understanding is that a disruption in the microbiome is linked to inflammation, irritation, dry, itchy skin, eczema, and even worsen some skin diseases.
But the idea that we can nudge skin towards better health through microbiome action is only just being studied scientifically, Dr. Westgate says.
“As more data becomes available, using sequencing methods to explore microbiomes, more generalizations might appear on products targeting the microbiome across body sites, age, gender, and conditions. However, until we know more, microbiomes should still be considered as unique and individual and strongly linked to the status of the skin at each body site.”
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However, good skin care should ultimately lead to a good microbiome. And a move towards gentler aesthetics and dermatology treatments and milder, wash-off products will be beneficial to the skin in general and less damaging to the outer layer of the epidermis, she suggests.
“The skin care industry has vast experience in improving healthy skin, especially though adding in or locking in moisture and via skin conditioning actives, which we predict will lead to a healthy microbiome. Temporary changes to lipid or water levels in the skin might result in a temporary shift in some species, and it is widely believed that environmental stressors contribute to these shifts. However, the underlying microbiome is very resilient and will re-establish again in healthy skin, once the external or internal factors are removed or corrected.”
She said future products and treatments targeting the microbiome will use technologies designed to adjust the microbiome balance – the dysbiosis – while reducing the need for added antimicrobials.
The Gut and the Skin
And what about the gut microbiome, does that impact skin health?
“Like skin, a healthy gut is associated with a healthy gut microbiome and although direct causal relationships between gut dysbiosis and poor skin health is not yet available, there is significant data that suggests that a healthy gut microbiome has overall health benefits which would include for skin.”
She says it has been proven that the gut microbiome is essential in regulating the intestinal permeability, metabolism, and immune system.
“Gut microflora short-chain fatty acids (SCFA) such as butyric acid have recently been shown to have benefits to skin and hair tissues suggesting that both gut and skin SCFA are helpful ‘postbiotic’ metabolites. But more clinical research is needed to support claims for direct skin benefits from gut microbiome-directed products and to identify causal relationships between gut and skin dysbiosis.”