Cosmeceutical Critique

The role of the skin microbiome in skin care

Publish date: November 13, 2018

Microbiome effects on skin function

The skin barrier, a bilayer lipid-laden membrane that surrounds keratinocytes and prevents transepidermal water loss, is affected by resident microbial communities and has been shown by research to be influenced by the volume and diversity of such microbes.¹⁸ Organisms on the skin’s surface play an important role in communicating with and educating the cutaneous arm of the immune system.¹⁹ In 2017, Maguire and Maguire reviewed recent studies of the gut and skin microbiomes and suggested that Nitrobacter, Lactobacillus, and Bifidobacterium can improve skin health and could be useful bacterial adjuvants in a probiotic and prebiotic strategy in homeostatic renormalization when skin health is compromised.²⁰Nitrobacter has displayed antifungal activity against dermatophytes and Staphylococcus; Lactobacillus has exhibited anti-inflammatory effects and was shown to improve adult acne in a small study; Bifidobacterium combined with Lactobacillus lowered the incidence of atopic eczema in early childhood; and Bifidobacterium and the prebiotic galacto-oligosaccharide prevented hydration level losses in the stratum corneum among other beneficial effects in a double-blind, placebo-controlled, randomized trial.²⁰

Microbiome diversity is key

Microbes interact, collaborate, and oppose one another while exerting influence and being affected by the host. Effective communication among the innate and adaptive parts of the immune system, epithelial cells, and cutaneous microbiota is essential for optimal functioning of the skin.^6,7 Studies on subjects with atopic dermatitis showed a strong association between decreased diversity and increased disease severity. This suggests that a diverse microbiome is associated with skin health.²¹ For this reason, use of pre- and probiotics for skin issues is discouraged at this time. If we replace the normal diverse flora with one organism, we do not yet know the consequences. It is much more likely that successful treatments in the future will contain a diverse group of organisms.

Cosmeceutical effects on the skin microbiome

Cleansing and use of emollients certainly affect the skin biome, but we do not yet know to what extent. A study that looked at the effects of emollients on infants with atopic dermatitis showed that the emollient group has a lower skin pH and a more diverse microbiome.²² In a 2016 study on the impact of acute treatment with topical skin cleansers on the cutaneous microbiome, investigators evaluated multiple common skin cleansers in the washing of human forearms. Group A Streptococcus growth was reduced after washing with soaps infused with such antimicrobial compounds as benzalkonium chloride or triclocarban. The researchers stipulated that much more research is necessary to ascertain the effects of chronic washing as well as the that role skin care products may play in skin homeostasis or dysbiosis in some individuals.²³

In a 2017 analysis of the effects of cosmetics on the skin microbiome of facial cheeks with high- and low-hydration levels over 4 weeks, Lee et al. found that bacterial diversity was higher in the low-hydration group, with increases in both observed after the use of cosmetics. The high-hydration group showed a greater supply of Propionibacterium. Cosmetic use was found not to have caused a shift in bacterial communities in the low-hydration group.²⁴

Dr. Leslie S. Baumann

Conclusion

We are in the early stages as we strive to learn more about the microbiome to leverage such knowledge to improve skin health. In the meantime, there is not enough evidence to suggest the use of any oral or topical prebiotics or probiotics to improve skin health. In fact, we may be causing harm by lessening diversity. The New York Times recently published an article called “The Problem with Probiotics” that referenced a JAMA Internal Medicine article entitled “Probiotic Safety – No Guarantees.”²⁵ I recommend that you read those. Next month, I will look more closely at microbiome research pertaining to skin disease.

Dr. Baumann is a private practice dermatologist, researcher, author and entrepreneur who practices in Miami. She founded the Cosmetic Dermatology Center at the University of Miami in 1997. Dr. Baumann wrote two textbooks: “Cosmetic Dermatology: Principles and Practice” (New York: McGraw-Hill, 2002), and “Cosmeceuticals and Cosmetic Ingredients,” (New York: McGraw-Hill, 2014), and a New York Times Best Sellers book for consumers, “The Skin Type Solution” (New York: Bantam Dell, 2006). Dr. Baumann has received funding for advisory boards and/or clinical research trials from Allergan, Evolus, Galderma, and Revance. She is the founder and CEO of Skin Type Solutions Franchise Systems LLC.