Skin Microbiome

Your Gut Microbiome Communicates with Your Skin Biome for Healthy Skin

Your skin has its microbiome, which, like the gut microbiome,  trains and supports local immune function and keeps harmful bacteria at bay. Much less known about the skin microbiome, but this rapidly emerging cosmetic medicine field will change how we treat our skin and challenge what we thought we knew. It is understood that skin health and barrier function, though primarily our skin microbiome’s responsibility, is impacted and controlled by our gut microbiome. When in balance, the good organisms living on our skin obtain nutrients from cell debris and sebum and produce products that help us defend against pathogens (plus many other functions).

The skin microbiome varies across your body.

The skin presents a very different environment from the gut; it is acidic (sour), salty from sweat, and the surface is mainly dry (except in the folds). It presents diverse surfaces, from areas coated in an oil-rich sebaceous material inside the oil-rich hair follicles or arid foot environments. The skin microbiome varieties vary across the body, depending on the microenvironment. (feet have an entirely different microbiome than your armpits!) But the skin’s outside surface is other from the neutral, moist,  food-rich gut environment, which houses many more microbes than the skin surface. However, around 1000 species of bacteria live on your skin, as well as a range of other species like viruses, fungi, archaea and even mites!

Our skin microbiome helps build our immune system.

Certain bacteria that arrive at birth train our immune system to accept good bacteria and reject harmful bacteria, so our skin bugs are significant for stopping infection. As we progress through life, the skin microbes continue to change and diversify until puberty. So good bacteria help communicate with our skin and immune cells, helping the skin barrier function and settling inflammation. It is a two-way street. A healthy barrier also supports good bacteria, such as the Staph epidermis, which produces antimicrobial antibodies to kill harmful bacteria and keep Staph aureus at bay. It is a win-win for us and our resident bugs!

The skin microbiome – healthy biome – happy skin

Maintaining the balance and function of the skin ecology is much more complex, though; as with the gut, it is the balance of the bacteria that is important. So a species can live on the skin and not cause harm. However, if it overgrows or becomes dominant, it can cause damage, as in acne, rosacea, eczema, and dandruff. On the other hand, when our resident bugs are in balance, our skin barrier is intact and healthy, and our skin is happy.

Nature 588, S209 (2020)

doi: https://doi.org/10.1038/d41586-020-03523-7