There are 10 times more bacteria living in your gut and on your skin than there are cells in your body. It’s no wonder this microscopic ecosystem has the power to influence the look and function of skin. Research into how the skin microbiome impacts conditions like acne and dermatitis, as well as our ability to influence the microbiome as a means to control these conditions, is ongoing [1]. Do we have the power to affect the different microorganisms on our skin? Can we optimize our skin care practices to make positive changes? We’ve compiled the current information so you can make the most out of your skin microbiome.
What is the skin microbiome?
Often used interchangeably, microbiota and microbiome have subtle differences. The skin microbiota refers to all of the microorganisms found on the skin including fungi, yeast, viruses, mites, and bacteria. The skin microbiome refers specifically to the collection of genes and genetic makeups of those microbiota. The term microbiome is more descriptive as it allows the genetics to get specific about what species of bacteria or microbiota reside in a certain location and what tasks the species may carry out.
Why is the skin microbiome important?
Studies from The Human Microbiome Project found that the microbiome of the human body contains more than 8 million unique genes. When compared to the total number of human genes, this suggests that the genetic contribution of the microbiome to the human body may be many hundreds of times greater than the genetic contribution from our native genetics genes [2]. Each of these genes from the microbiome carries out a different process, some good, like helping to secrete skin-barrier repair compounds, and some bad, like creating imbalances that can cause rashes or acne [2].
What does the microbiota do for our skin?
Think of your skin like a lawn, where the soil is our skin and the grass and weeds are the microorganisms that live there. Just like the grass and weeds use the soil to live and grow, microorganisms consume oils, dead skin and nutrients from the skin’s surface to survive. In exchange, the plants help nourish the soil by excreting helpful compounds; they help prevent erosion, and create a barrier to protect the soil from the elements. Like a lawn, skin has a balance between good bacteria (grass) and bad bacteria (weeds). Since they compete for resources, the more grass there is, the less likely there are to be weeds. Skin has a delicate balance too. We need the microbiota on our skin to help act as a line of defence against pathogens and harmful substances, help maintain the protective moisture barrier and keep if flexible, youthful, and strong [3]. Additionally, a balanced skin microbiome can offset factors that lead to redness, dryness, and a weakened surface [3].
How can a person impact their microbiota?
When we use products or engage in behaviours that kill microorganisms, we risk throwing the skin microbiome out of balance. This is because many actions like spending time in UV light, using harsh soaps, applying antibacterial agents like hand sanitizer, or altering the pH of our skin, kills microorganisms both good and bad [3]. This often leads to disruptions in the moisture barrier and leads to inflammation, exacerbating conditions like acne, rosacea, dermatitis, psoriasis and visible signs of aging [3].
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What can we do to ensure a healthy skin microbiome?
Studies show that we can positively influence our skin microbiome by avoiding the use of harsh foaming agents, remove pollution at night by cleansing with a gentle cleanser, use pH balanced products (those that have a pH similar to that of skin), and use skin care ingredients that support the growth of healthy bacteria [2].
Microbiome supporting ingredients include:
Probiotics – Probiotics are live bacteria, the application of which has been shown to temporarily improve the skin microbiome by increasing the levels of healthy bacteria and decreasing pathogenic (or bad) bacteria. Applying probiotic-fortified skin care products may be a way to restore the skin microbiome after it has been damaged by antibiotics or environmental stressors [4]. Ultimately, the skin microbiome contains thousands of strains of probiotics and each person's skin microbiome is unique. There are generally accepted "good" strains of bacteria but a skin care product is not a replacement for a native microbiome. Additionally, keeping live bacteria alive in a skin care product is difficult. Most preservatives designed to keep skin care ingredients fresh, are also designed to kill bacteria. These products would have to be kept refrigerated and would have a short shelf life. Most skin care products containing probiotics may have been manufactured with live cultures but its more than likely that by the time they get to your face, the probiotic cultures are dead.
Prebiotics – Prebiotics are food for bacteria. Applying prebiotics to the skin help to encourage the growth and balance of healthy bacteria [3]. Some of the most studied prebiotics for skin health include plant sugars and fibres such as xylitol and rhamnose as well as fruit extracts (as they contain a large group of molecules know as fructooligosacharides). There are also specific prebiotics like glucomannan that encourage the growth of probiotics that help control acne.
Postbiotics – Postbiotics are the helpful compounds produced by healthy bacteria that have been shown to keep the skin barrier balanced. They are a result of the fermentation carried out by bacteria. In the culinary world postbiotics are well recognized and include soft cheeses, yogurt, kombucha, sauerkraut, pickles, and tempeh to name a few. When it comes to skin care these ingredients include enzymes, peptides, proteins, acids and glycerol. These compounds can exhibit a range of skin supporting benefits including exfoliation, hydration, calming, and moisturization of the skin.
Probiotic Lysates – These are the actual dead bacterial cells where the cell membrane that holds them together is broken apart and the contents of the cells are exposed. Studies show that applying probiotic lysates from certain strains of bacteria to the skin, helped to increase the expressions of proteins that makeup the outer skin barrier [6]. This has been shown to help prevent inflammation in the skin (the root of most skin problems)[6]. Scientists aren’t exactly sure why applying these preparations to the skin provides these benefits but it’s hypothesized that our cells recognize the presence of certain microbiota and respond in a positive way [6].
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Beyond skin care products there are lifestyle practices you can implement to help keep your skin microbiome balanced. This includes sweating regularly to help open the pores and balance the skin pH, eating a balanced diet with plenty of prebiotic fibre rich foods like garlic, onions, and oats, and protecting your skin from UV light with a broad-spectrum sunscreen. There are also chemical changes that occur in the skin when a person experiences stress, so incorporating activities into your day that help to reduce mental load can also contribute to a balanced microbiome [5].
Healthy skin takes a village! An ecosystem of microbiota to be specific. From skin care to wellness practices, keeping your skin looking and feeling its best starts with balance. After all, great skin comes from more than just great skin care products.
[4] Grice EA, Segre JA (2013) The Skin Microbiome. Nat Rev Microbiol 9(4): 244-253
[6] Jung, Y. O., Jeong, H., Cho, Y., Lee, E. O., Jang, H. W., Kim, J., ... & Lim, K. M. (2019). Lysates of a probiotic, lactobacillus rhamnosus, can improve skin barrier function in a reconstructed human epidermis model. International journal of molecular sciences, 20(17), 4289.