How your skin microbiome defines your health, and how to cultivate the best skin microbes
Western medicine is still coming to terms with the discovery that the microorganisms living in our gut have so many effects our health. Understanding how gut microbes interact with our immune and nervous systems has led to a new way of thinking about a broad range of diseases, including diabetes, obesity and mental health. However, our gut microbes are only part of the story. The microbes living on our skin may be equally important, and our lifestyle and environment determine whether they have a positive or negative impact on our health.
How do our skin microbes affect our health?
Studies over the last few decades have shown that humans living in rural environments have a lower risk of developing allergic and other immune-mediated diseases, including asthma and eczema. There is strong evidence that the protective effect of a rural environment is due to exposure to soils rich in non-pathogenic microbes, including species of Acinetobacter bacteria. In one study, children living in a rural environment had a 10-fold reduction in the incidence of eczema compared to urban populations nearby, and 3-4 times higher numbers and diversity of species of Acinetobacter bacteria living on their skin.
Similarly, owning a dog is known to reduce the risk of eczema in children, although it’s not clear whether exposure to the dog’s microbes, or the outdoor lifestyle associated with owning a dog that is responsible for this protective effect.
Studies have shown that certain bacteria living in soil, including Acinetobacter, can trigger local immune responses in the skin which then steer the immune system away from allergic type inflammation. This ‘training’ of the immune system by microbes living in the skin is probably why exposure to these bacteria in early life is protective against many allergic type diseases.
As our lives become more urbanised, with reduced access to rural environments and green spaces, we risk losing microbial species from our skin’s microbiome. In general terms, reduced diversity of microbes in our skin also increases our risk of developing allergic and immune diseases, as well as mental health disorders and other conditions influenced both by the microbiome and the immune system (summarised in 1).
In addition to its role in suppressing allergic diseases, a healthy skin microbiome can protect us against infections with pathogenic strains of bacteria (we have written about this effect here)
How to nurture the right microbes in our skin
It is clear that the microbial environment we are exposed to as children exerts a strong influence on how our immune system develops. Exposure to natural environments, perhaps in the company of pets, will help children develop a varied and healthy skin microbiome and therefore a healthy immune system.
There has been a trend in modern urban life towards extreme cleanliness. When we use sanitisers and disinfectants in our homes we risk wiping out the good bacteria along with the bad, and reducing the diversity of microbes in our homes, and therefore on our skin. Cleaning our homes with products like vinegar, bicarb soda and natural soap and water is safer.
Hand-washing our dishes, instead of using a dishwasher, which kills more microbes, is another way to improve the diversity of good bacteria. In one study, children in families that hand-washed dishes had a reduced incidence of allergies, suggesting that the higher exposure to bacteria was protective (2).
We should also consider how we wash our skin. Antibacterial soaps have the potential to upset our skin’s microbial balance, and most health experts now advise against them (read our article on this here). In addition, harsh detergents can damage the skin’s barrier and allow colonisation by pathogenic microbes, while increasing the risk of sensitisation and allergy development. (Read our article on the importance of the skin’s barrier here).
Finally, we should think carefully about what products we apply to our skin. Virtually all skin care products contain preservatives, which are are powerful antimicrobial chemicals that prevent the growth of bacteria and fungi. Preservatives remain in contact with our skin until the next time the skin is washed, which allows plenty of time for them to upset the skin’s microbial balance. This is just one of the reasons our certified organic skin care range is made without preservatives - in fact it is one of a handful of ranges world-wide that is preservative-free.
Mokosh products are made using only skin-compatible botanical ingredients that will protect and rebuild the skin’s barrier, without upsetting the balance of microbes living in the skin. In addition, they are free of emulsifiers, which are detergent-like molecules included in almost all skin care to allow the mixing of water and oil. As you can imagine, these detergent-like molecules can upset the skin’s barrier function, potentially allowing upsetting the skin’s microbial balance (read more about the problems with emulsifiers in skin care here).
It is becoming clear that a return to a simple lifestyle that embraces the outdoors, together with a relaxed attitude to home hygiene can save our children, and our health system, a lot of unnecessary suffering. Combining this with a diet that is rich in natural, unprocessed foods, and minimising exposure to toxic and synthetic chemicals both in our homes and our skin care will go a long way towards helping us live healthier, happier lives.
1. Prescott, S.L. et al (2017) The skin microbiome: impact of modern environments on skin ecology, barrier integrity and systemic immune programming. World Allergy Organ J. 10:29
2. Hesselmar, B. et al (2015) Allergy in children in hand versus machine dishwashing Pediatrics 135, e590