From the laundry detergent you use, perfumes, cosmetics, and even "all natural" lotions you apply, you leave an imprint on your skins microbiome. Does it last? Is it for the better? Or for the worse. How might going the alternative, herbal, route to skincare affect your overall health? I try to answer these questions and more with an analysis of the most recent research published. Lets say hello to your skins microbiome, you never walk alone.
You are a walking ecosystem. Full of life and energy, resourcefulness and, on some days, even war -- just ask your bacteria. If you were ever bored you may have started picking at your skin. You'll have noticed that there are thinner and thicker parts of your skin, hairier, and sweater parts as well [1-2]. Each of these settings provide their own unique ecosystem for bacteria to thrive in. While little is actually known on what makes a "healthy skin microbiome" a lot can be shown for the differences between each location and its response to external stresses. The general consensus is that a characteristic of a healthy microbiome is high diversity [3-4].
By diversity I mean to describe the number of different species of bacteria present in a specific area. Higher bacterial diversity = greater health benefits [3-6]! This is because each species of bacteria offer different potential health benefits, some of which are repeated among your many species. Anything and everything from UV exposure, hydration, synthetic products, and stress can put your microbiome into disarray . If one species starts struggling and diminishes in number, due to the lack of resources or a disturbance to your skin, another species with the same benefits may survive to provide those benefits [4-5]. Thus there is a balance and a value in the bacteria living on your skin, and why we want a lot of them.
Higher bacterial diversity = greater health benefits
Understandably you may be wondering how cosmetics may play a role in your microbiome. After all, in the United States the average number of cosmetics used is 12 products a day for women and 6 for men . With the rise in the beauty industry we are certainly not at a loss of makeup, moisturizers, and face washes. While I can't directly answer what your specific products are doing, as every product is different and every individuals microbiome is even more drastically unique, I can share some research on how the skin microbiome is affected by synthetic and plant based skincare:
One study in Korea investigated how the use of cosmetics affected the face microbiome . They divided the women into groups according to their initial skin hydration (high vs low) and provided them with a "basic" moisturizer, formulated with synthetic ingredients that they had to use for 4 weeks. Their hope was to observe a difference in bacterial diversity between moisturizing dry vs hydrated skin types. After 4 weeks they showed that all groups had an increase bacterial diversity. While you may think this isn't too revolutionary, further details of their results showed women with characteristically dry skin ended the study with the same quality of skin and hydration as those that started out with high levels! The catch? Their microbiome did not look similar to the women of the high hydration group.
This study leaves us with more questions than answers: What affects the species found on your skin? And why do drier skin types not resemble hydrated skin microbiome when moisturized? One cool piece of information they did show is use of this particular moisturizer resulted in lower amounts of acne causing bacteria on the face, suggesting that moisturizing your face may reduce breakouts .
Synthetic vs Natural Ingredients
A lab in the United Kingdom decided to investigate if synthetic ingredients are better than natural ingredients . They gave 30 women one of three products: a leading "synthetic" moisturizer (75% synthetic ingredients), a "natural" moisturizer (70% synthetic ingredients, showing why its important to check the label of "natural" products), and a plant based moisturizer (0% synthetic ingredients). The researchers believed there would be a decrease in bacterial diversity in the synthetic groups, due to synthetic ingredients being "alien" to the skin. However after 4 weeks of treatment, all test groups showed an increased bacterial diversity, with the largest degree of change in the plant based test group.
Whats going on here!? Shouldn’t synthetic ingredients be bad? One thing the researchers did not factor into their experiment, is if the women being tested had a history with synthetic ingredients. Its most likely that they not only used synthetic products (because of their wide availability), but also that they used many of them, which would greatly impact their microbiome. This experiment limited these women to only one cosmetic, potentially leading in a form of relief for the test subjects skin, as it would be considerably less synthetic ingredients used. Ultimately the plant based skincare group showed the greatest results with the highest change in microbial diversity, indicating we may want to swap out our products for plant based cosmetics .
Coconut oil for infants
The last paper I'll discuss is more to the potential of plant based skincare. This paper detailed an experience of nurses working with premature infants . Pre-term infants are at a high risk of late onset sepsis or LOS (infection of the blood) due to their reduced immunity and underdeveloped epidermal tissue [learn about epidermal tissue here]. Coconut oil is believed to help improve skin integrity while also providing antimicrobial effects. Studies have shown topically applying coconut oil to wounds resulted in faster healing and more collagen synthesis than wounds left untreated .
In this study with the infants, the group treated with coconut oil showed an improved skin integrity, fewer cases of LOS, and no adverse effects to the treatment. While this study did not sample the microbiome, it may suggest that use of the plant based oil resulted in a safe and protective cosmetic for delicate skin and for those at very high risk of bacterial infections .
Microbiome research is currently focused more on gut health than the skin. I hope that by sharing these studies you may become more aware of what you apply onto your largest organ, and potentially inspire some to investigate plant based skincare. Read about these experiments and more in the papers cited in references below.
1- Oh, J., Byrd, A. L., Deming, C., Conlan, S., Kong, H. H., & Segre, J. A. (2014). Biogeography and individuality shape function in the human skin metagenome. Nature, 514(7520), 59-64. 2- Nakatsuji, T., Chiang, H. I., Jiang, S. B., Nagarajan, H., Zengler, K., & Gallo, R. L. (2013). The microbiome extends to subepidermal compartments of normal skin. Nat Commun 4: 1431. 3- Balvanera, P., Pfisterer, A. B., Buchmann, N., He, J. S., Nakashizuka, T., Raffaelli, D., & Schmid, B. (2006). Quantifying the evidence for biodiversity effects on ecosystem functioning and services. Ecology letters, 9(10), 1146-1156. 4- Grice, E. A., & Segre, J. A. (2011). The skin microbiome. Nature reviews microbiology, 9(4), 244-253. 5- Kong, H. H., & Segre, J. A. (2012). Skin microbiome: looking back to move forward. Journal of Investigative Dermatology, 132(3), 933-939. 6- Flint, H. J. (2012). The impact of nutrition on the human microbiome. Nutrition reviews, 70(suppl_1), S10-S13. 7- Moskovicz, V., Gross, A., & Mizrahi, B. (2020). Extrinsic Factors Shaping the Skin Microbiome. Microorganisms, 8(7), 1023. 8- EWG, Exposures add up – Survey results. Exposures add up – Survey results http://www.ewg.org/skindeep/2004/06/15/exposures-add-up-survey-results/ (2004) 9- Lee, H. J., Jeong, S. E., Lee, S., Kim, S., Han, H., & Jeon, C. O. (2018). Effects of cosmetics on the skin microbiome of facial cheeks with different hydration levels. Microbiologyopen, 7(2), e00557. 10- Wallen-Russell, C. (2019). The role of every-day cosmetics in altering the skin microbiome: A study using biodiversity. Cosmetics, 6(1), 2. 11- Strunk, T., Pupala, S., Hibbert, J., Doherty, D., & Patole, S. (2018). Topical coconut oil in very preterm infants: an open-label randomised controlled trial. Neonatology, 113(2), 146-151. 12- Nevin, K. G., & Rajamohan, T. (2010). Effect of topical application of virgin coconut oil on skin components and antioxidant status during dermal wound healing in young rats. Skin pharmacology and physiology, 23(6), 290-297.