Prebiotic Type Spotlight: Skin Microbiome - April 2024 Edition
Each edition of GPA’s Prebiotic Spotlight focuses on a specific prebiotic type to raise awareness about the prebiotic itself, its sources, any notable and/or recent research, and how it is used in the marketplace. In this issue, GPA highlights one of the microbiome locations in the host influenced by prebiotics and prebiotic effect, the skin microbiome.
Overview
The skin is the largest and most exposed organ in the human body. Its microbiota is comprised of all the diverse microbial communities, including bacteria, viruses, fungi, and mites that colonize the skin’s surface area, which together with their collective genomes are known as the skin microbiome (Whiting et al., 2024; Yang et al., 2024). There are specific characteristics distinguishing skin microbiome composition across individuals and within an individual at different life stages, which are influenced by factors like age, gender, genetics, environment, and hygiene (Vollmer et al., 2018). The skin microbiome has adapted to the skin’s environment, maintaining its barrier integrity, and contributing to the immune response in preventing pathogenic growth. Consequently, an imbalance in the skin microbiome composition has been recognized for its role in various dermatological conditions, such as acne, atopic dermatitis/eczema, rosacea, psoriasis, prurigo nodularis, and skin cancer (Egert & Simmering, 2016; Woo & Kim, 2024). Recent research has shown that prebiotics such as alpha-glucan oligosaccharide, fructo-oligosaccharides, galacto-oligosaccharides, human milk oligosaccharides, inulin, and lactulose as well as synbiotics (Phan et al., 2023; Rahman et al., 2023; Woo & Kim 2024) may help improve symptoms of a variety of dermatological conditions.
Characteristics of the Skin Microbiome
The skin microbiome has some distinct characteristics that differentiate it from other microbiome locations in the human body. These include:
- The total number of microbes on the skin of a healthy adult ranges from 108 to 1010 (Egert & Simmering, 2016).
- While the composition of this niche is fairly stable across human beings, some features unique to every individual exist (Whiting et al., 2024). It is mostly transient species that account for the interpersonal differences, which are commonly influenced by external environmental factors (i.e., climate and geography), host immune status, host pathophysiology, and historical exposure (Grice & Segre, 2011).
- Over 1000 microbial species belonging to 19 phyla have been identified on the human skin, predominantly belonging to four phyla, including Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria (Woo & Kim, 2024; Yang et al., 2024).
- Microbial composition and diversity experience age-related changes, with increased alpha diversity (species richness and abundance within a specific sample) in older individuals (Walters & Martiny, 2020; Woo & Kim, 2024).
- The abundance of Actinobacteria decreases in older adults, while that of Firmicutes, Bacteroidetes, and Proteobacteria increases with aging (Woo & Kim, 2024).
Benefit Areas
Increasing research points towards an association between the composition of the skin microbiome and skin health and disease manifestations, especially with age-related changes. Some of the noteworthy roles of the skin microbiome include:
- Skin health maintenance by supporting skin barrier function and homeostasis through numerous mechanisms, including competing and fighting off pathogenic microbes on the skin barrier and secreting antimicrobial proteins and proteases to interfere with pathogenic colonization of the skin (Liu-Walsh et al., 2021; Yang et al., 2024). Topical prebiotics may support the skin microbiome via various actions, as seen with a 1% colloidal oat moisturizer that affected the growth, metabolism, lactic acid production, and gene expression of the skin commensal bacteria (Liu-Walsh et al., 2021).
- Inflammatory conditions management, including atopic and seborrheic dermatitis, by beneficially modifying the microbiome and producing anti-inflammatory metabolites (Phan et al., 2023; Tao et al., 2021). Both topical and oral prebiotics may normalize skin microbiota and preserve skin barrier integrity to prevent or improve the manifestations of atopic dermatitis by contributing to the anti-inflammatory effect (Al-Ghazzewi & Tester, 2014; Passeron et al., 2006; Phan et al., 2023).
- Immune response contribution by producing or regulating keratinocytes, innate antimicrobial peptides, and immune cell expression (Smythe & Wilkinson, 2023; Yang et al., 2024). Topical and oral prebiotics may also contribute to this effect by modulating the skin and gut bacteria, respectively, providing immune-enhancing effects by supporting lactic acid bacteria, short-chain fatty acids production, and modifying mucin production (Al-Ghazzewi & Tester, 2014).
- Wound healing induction by commensal skin microbes and their modulation (Yang et al., 2024). Prebiotics have not been studied as well as probiotics for wound healing, but with their anti-inflammatory and immunomodulatory effects, future studies may investigate the effects of prebiotics in wound healing.
Recent Research
On ClinicalTrials.gov, there are eighteen studies currently recruiting to study the skin microbiome and its association with various skin conditions, including atopic dermatitis, vitiligo, and others, including one study in patients with eczema assessing the effects of using colloidal oatmeal as part of the intervention on skin microbiome (ClinicalTrials.gov, 2024). Searching the terms “prebiotics” AND “skin microbiome” on PubMed yields 16 studies, with the earliest reference from 2017 (PubMed, 2024). Limiting the search to recent publications from 2024 restricts the search to one study by Whiting et al. titled “The Skin Microbiome and its Significance for Skin Dermatologists.” The study discussed the importance of the skin microbiome in human health, and the potential benefits of using topical prebiotics, postbiotics, and oral probiotics, as shown by accumulating clinical research, for the treatment of dermatologic conditions and the stabilization of skin microbiome imbalance (Whiting et al., 2024).
Another publication by Grant et al. (2024) reviewed the literature surrounding the impact of ultraviolet radiation (UVR) and sunscreen on the skin microbiome. The study found that UVR differentially impacts the skin microbes, which include direct bacterial effects, alterations in the cutaneous metabolome, and changes in the cutaneous immune system. Furthermore, sunscreen compounds and emulsions negatively impact cutaneous microbes and reduce the diversity of skin microbiome. As such, to maintain a healthy skin microbiome that protects the skin barrier and contributes to skin health, it is critical to improve the contents of sunscreens that both protect against UVR and preserve the skin microbiome (Grant et al., 2024).
How is the presence of the skin microbiome products on the market?
The presence of skin microbiome products on the market has increased in the last few years prompted by increasing consumer awareness about the significance of this microbial niche for skin and overall body health.
The global skin microbiome market was estimated at USD 794.93 million in 2022, with an anticipated compound annual growth rate (CAGR) of 13.68% to reach a value of USD 2,217.18 million in 2030 (Data Bridge Market Research, 2023).
References
Al-Ghazzewi, F. H., & Tester, R. F. (2014). Impact of prebiotics and probiotics on skin health. Beneficial microbes, 5(2), 99–107. https://doi.org/10.3920/BM2013.0040
ClinicalTrials.gov. Accessed 2024 Apr 10. Available from: https://clinicaltrials.gov/search?term=Skin%20Microbiome&cond=Skin%20Microbiome&intr=skin%20microbiome&aggFilters=status:rec
Data Bridge Market Research. (2023, September). Global Skin Microbiome Market – Industry Trends and Forecast to 2030. Accessed on 2024 Mar 26. Available from: https://www.databridgemarketresearch.com/reports/global-skin-microbiome-market.
Egert, M., & Simmering, R. (2016). The Microbiota of the Human Skin. Advances in experimental medicine and biology, 902, 61–81. https://doi.org/10.1007/978-3-319-31248-4_5.
Grant, G. J., Kohli, I., & Mohammad, T. F. (2024). A narrative review of the impact of ultraviolet radiation and sunscreen on the skin microbiome. Photodermatology, photoimmunology & photomedicine, 40(1), e12943. https://doi.org/10.1111/phpp.12943
Grice, E. A., & Segre, J. A. (2011). The skin microbiome. Nature reviews. Microbiology, 9(4), 244–253. https://doi.org/10.1038/nrmicro2537
Liu-Walsh, F., Tierney, N. K., Hauschild, J., Rush, A. K., Masucci, J., Leo, G. C., & Capone, K. A. (2021). Prebiotic Colloidal Oat Supports the Growth of Cutaneous Commensal Bacteria Including S. epidermidis and Enhances the Production of Lactic Acid. Clinical, cosmetic and investigational dermatology, 14, 73–82. https://doi.org/10.2147/CCID.S253386
Passeron, T., Lacour, J. P., Fontas, E., & Ortonne, J. P. (2006). Prebiotics and synbiotics: two promising approaches for the treatment of atopic dermatitis in children above 2 years. Allergy, 61(4), 431–437. https://doi.org/10.1111/j.1398-9995.2005.00956.x
Phan, S., Lee, J., Huynh, C., Hassan, O., Lio, P. (2023). Topical Prebiotics and Microbiome Metabolites: A Systematic Review of the Effects of Altering the Skin Microbiome in Atopic Dermatitis. Journal of Integrative Dermatology.
PubMed. Accessed 2024 Mar 25. Available from: https://pubmed.ncbi.nlm.nih.gov/?term=%28prebiotics%5BTitle%2FAbstract%5D%29+AND+%28skin+microbiome%5BTitle%2FAbstract%5D%29&sort=
Rahman T, Sarwar PF, Potter C, Comstock SS, Klepac-Ceraj V (2023). Role of human milk oligosaccharide metabolizing bacteria in the development of atopic dermatitis/eczema. Frontiers in Pediatrics, (11), 1090048. https://doi.org/10.3389/fped.2023.1090048
Smythe, P., & Wilkinson, H. N. (2023). The Skin Microbiome: Current Landscape and Future Opportunities. International journal of molecular sciences, 24(4), 3950. https://doi.org/10.3390/ijms24043950
Tao, R., Li, R., & Wang, R. (2021). Skin microbiome alterations in seborrheic dermatitis and dandruff: A systematic review. Experimental dermatology, 30(10), 1546–1553. https://doi.org/10.1111/exd.14450
Vollmer, D. L., West, V. A., & Lephart, E. D. (2018). Enhancing Skin Health: By Oral Administration of Natural Compounds and Minerals with Implications to the Dermal Microbiome. International journal of molecular sciences, 19(10), 3059. https://doi.org/10.3390/ijms19103059
Walters, K. E., & Martiny, J. B. H. (2020). Alpha-, beta-, and gamma-diversity of bacteria varies across habitats. PloS one, 15(9), e0233872. https://doi.org/10.1371/journal.pone.0233872.
Whiting, C., Abdel Azim, S., & Friedman, A. (2024). The Skin Microbiome and its Significance for Dermatologists. American journal of clinical dermatology, 25(2), 169–177. https://doi.org/10.1007/s40257-023-00842-z
Woo, Y. R., & Kim, H. S. (2024). Interaction between the microbiota and the skin barrier in aging skin: a comprehensive review. Frontiers in physiology, 15, 1322205. https://doi.org/10.3389/fphys.2024.1322205
Yang, Y., Huang, J., Zeng, A., Long, X., Yu, N., & Wang, X. (2024). The role of the skin microbiome in wound healing. Burns & trauma, 12, tkad059. https://doi.org/10.1093/burnst/tkad059