Beauty of microbes: How targeting the gut microbiome supports skin health

There is a growing body of evidence that demonstrates a relationship between the gut microbiome and skin health. This relationship, more specifically, involves immune response. “The microbiome plays a direct role in regulating the equilibrium between pro-inflammatory and anti-inflammatory responses within the gut,” says Paula Simpson, founder, Nutribloom Consulting, a nutricosmetics innovation, formulation, and brand expert. “In the context of skin health, there is a strong link between the gut and skin microbiomes. Many skin conditions, including atopic dermatitis, psoriasis, acne vulgaris, and dandruff, are associated with imbalances in both the gut and skin microbiota. The microbiome serves as a key regulator of immune function, maintaining homeostasis through bidirectional communication with tissues and organs. When this balance is disrupted (dysbiosis), it can lead to an altered immune response, contributing to inflammatory skin disorders.”

There are a surprising number of similarities between the skin and gut barriers as they are both very innervated and vascularized organs essential for immune and neuroendocrine function.¹ For example, both the gut’s inner surface and the skin’s outer surface are covered with epithelial cells that are exposed to exogenous environments, making them continuously primed to distinguish between harmful and beneficial compounds. Additionally, both the skin and gut have a microbial environment. On the skin, the microbiome trains the immune cells on the skin to determine the well-being of the host, while in the gut microorganisms play an essential role in metabolic and immune function by metabolizing indigestible complex polysaccharides into essential nutrients such as vitamin K, B₁₂, butyrate and propionate.¹

A number of factors can potentially be attributed to dysbiosis and the resulting immune response, including diet and hygiene. The Western diet, characterized by processed foods, high sugar, as well as saturated and trans fats² has been linked to immune-mediated inflammatory diseases such as rheumatoid arthritis, psoriasis, and atopic dermatitis.¹ There’s also the hygiene hypothesis that implies that current modern health practices have led to a reduction in our exposure to microbes, leading to an increase in inflammatory diseases due to a lack of microbial stimulation.

Not governed by diet alone, there is also a bidirectional relationship between the gut and skin. For example, research has found that ultra-violet B exposure can lead to an increase in vitamin D levels as well as an increase in the alpha and beta diversity of the microbiome.³

Given the intricate relationship between the gut and skin, ingredients such as pre-, pro-, and postbiotics may be a viable way to support skin health. For example, supplementation with live microorganisms (probiotics), specifically Lactobacillus acidophilus, Lactobacillus delbrueckii subspecies bulgaricus, and Bifidobacterium bifidum, was shown in a prospective, randomized, open-label trial to be comparable to the drug minocycline in the treatment of mild to moderate acne.⁴ In fact, research has indicated that acne vulgaris patients have distinct microbiome composition, with decreased microbial diversity, a lower abundance of firmicutes, and an increased abundance of Bacteroides. Researchers also found that acne vulgaris patients were depleted in Clostridium, Clostridiales, Lachnospiraceae, and Ruminococcaceae.¹

Topically, postbiotics, which are inactive forms of microorganisms, offer a lot of flexibility to product formulators when compared to probiotics since there is no concern about preserving live microorganisms. One recent study found that a postbiotic formulation purified from the culture supernatant of the probiotic strain B. coagulans MTCC 5856, called LactoSporin from Sabinsa Corp. (East Windsor, NJ), was equivalent to benzoyl peroxide in the treatment of mild to moderate acne by significantly reducing sebaceous secretion, resulting in reduced oiliness, pimples, acne spots, and redness around acne spots.⁵

A combined approach may also be beneficial such as the combination of prebiotics and probiotics, often referred to as synbiotics. For example, one study found that a synbiotic formulationcontaining seven probiotic strains (including Lactobacillus casei , Lactobacillus acidophilus, Lactobacillus rhamnosus , Lactobacillus bulgaricus, Bifidobacterium breve, Bifidobacterium longum , Streptococcus thermophiles) with the prebiotic fructooligosaccharide, significantly improved symptoms of psoriasis when combined with hydrocortisone cream, compared to hydrocortisone cream alone.⁶ An immune-mediated inflammatory disease, psoriasis is associated with a relative higher abundance of Staphylococcus and Streptococcus species on the skin microbiome, and an increased risk of developing intestinal immune disorders such as inflammatory bowel disease, ulcerative colitis, and celiac disease.

The entire “biotics” category offers formulators a large toolbox with which they can create products that support the gut-skin axis. “Rather than relying solely on live probiotics, we can take two strategic approaches: first, by stimulating the growth of beneficial microbes through prebiotic fibers, and second, by directly supplementing with postbiotic metabolites to achieve similar functional benefits,” explains Simpson. “The broader category of ‘biotics’—including prebiotics, probiotics, postbiotics, and synbiotics—plays a crucial role in modulating the gut microbiota and influencing the production of microbially derived metabolites. These metabolites interact with the gut mucosal and immune systems and are now emerging as promising candidates for addressing signs of skin aging. As our understanding deepens, leveraging these biotic-based interventions may offer innovative strategies for promoting skin health and longevity.”

Outside of skin conditions, inflammation, an immune response, is recognized as one of the mechanistic pillars of aging. Chronic, sterile, low-grade inflammation, referred to as inflammaging,⁷ is a contributor to the pathogenesis of age-related diseases, while the body (and skin’s) immunological decline with advanced age, called immunosenescence, is considered a cause inflammaging.⁸ Therefore, considering the gut and skin microbiomes’ impacts on inflammation and immune health, the gut-skin axis may offer a novel mechanism by which to support skin health and aging.

References 

1. De Pessemier, B.; Grine, L.; Debaere, M.; Maes, A.; Paetzold, B.; Callewaert, C.Gut–Skin Axis: Current Knowledge of the Interrelationship between Microbial Dysbiosis and Skin Conditions. Microorganisms. 2021, 9 (2), 535. DOI:10.3390/microorganisms9020353
2. Clemente-Suarez, V.J.; Beltran-Velasco, A.I.; Redondo-Florez, L.; Martin-Rodriguez, A.; Tornero-Aguilera, J.F. Global Impacts of Western Diet and Its Effects on Metabolism and Health: A Narrative Review. Nutrients. 2023, 15 (12), 2749. DOI:10.3390/nu15122749
3. Bosman, E.S.; Albert, A.Y.; Lui, H.; Dutz, J.P.; Vallance, B.A. Skin Exposure to Narrow Band Ultraviolet (UVB) Light Modulates the Human Intestinal Microbiome. Front Microbiol. 2019, 10, 2410. DOI: 10.3389/fmicb.2019.02410
4. Jung, G.W.; Tse, J.E.; Guiha, I.; Rao, J. Prospective, randomized, open-label trial comparing the safety, efficacy, and tolerability of an acne treatment regimen with and without a probiotic supplement and minocycline in subjects with mild to moderate acne. J Cutan Med Surg. 2013, 17 (2), 114-122. DOI: 10.2310/7750.2012.12026
5. Majeed, M.; Majeed, S.; Nagabhushanam, K.; Mundkur, L.; Rajalakshmi, H.R.; Shah, K.; Beede, K. Novel Topical Application of a Postbiotic, LactoSporin^®, in Mild to Moderate Acne: A Randomized, Comparative Clinical Study to Evaluate its Efficacy, Tolerability and Safety. Cosmetics. 2022, 9 (3), 65. DOI: 10.3390/cosmetics9030065 
6. Akbarzadeh, A.; Alirezaei, P.; Doosti-Irani, A.; Mehrpooya, M.; Nouri, F. The Efficacy of Lactocare^® Synbiotic on the Clinical Symptoms in Patients with Psoriasis: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial. Dermatology Research and Practice. 2022, 4549134. DOI: 10.1155/2022/4549134
7. Franceschi, C.; Garagnani, P.; Parini, P.; Guiliani, C.; Santoro, A.Inflammaging: a new immune–metabolic viewpoint for age-related diseases. Nature. 2018, 14, 576-590. DOI:10.1038/s41574-018-0059-4
8. Pajak, J.; Nowicka, D.; Szepietowski, J.C.Inflammaging and Immunosenescence as Part of Skin Aging—A Narrative Review. Int J Mol Sci. 2023, 24 (9), 7784. DOI:10.3390/ijms24097784