GUT MICROBIOME AND SKIN HEALTH
Written by Dr Patrick Veiga, Research Director, PHD, HDR, Gut Microbiome & Nutrition at INRAE MetaGenoPolis / MICALIS Research Units.
Since the early days of microbiome research in the early 20th century, skin disorders such as eczema and acne were believed to originate from toxins produced in the gut (Bibb RHL, 1908). As early as 1908, probiotics like Lactozymase B were advertised in publications such as La Mode Moderne (cf. picture below)—the French equivalent of The Illustrated London News—for improving skin health via gut action.
Today, growing scientific evidence supports the notion that intestinal dysbiosis—characterized by reduced microbial diversity, decreased levels of anti-inflammatory species, and an increase in pathogenic and pro-inflammatory microbes—is frequently observed in common inflammatory skin diseases such as atopic dermatitis, psoriasis, rosacea, and acne vulgaris (Mahmud et al., 2022). Additional support for this connection comes from the high co-occurrence of gastrointestinal and skin disorders: notably, 10% to 25% of patients with inflammatory bowel disease (IBD) or celiac disease also suffer from skin conditions, including psoriasis (Jimenez-Sanchez et al., 2025).
The so-called "gut–skin axis" refers to a bidirectional communication pathway between the gut and the skin, which has been primarily studied in animal models. Key mediators of this dialogue include microbial metabolites such as short-chain fatty acids (SCFAs), microbial-derived vitamins, and neurotransmitters like GABA (Mahmud et al., 2022). Conversely, vitamin D—synthesized in the skin—plays a crucial role in regulating gut health and maintaining immune homeostasis. The immune system represents another important communication route: immune activation in one organ can influence immune responses in the other, with T cells playing a central role in this cross-talk (Mahmud et al., 2022).
In humans, clinical improvements in skin conditions following oral intake of probiotics provide additional evidence that what happens in the gut does not stay in the gut—it can have systemic effects, particularly on skin homeostasis (De Almeida et al., 2023).
Diet is a key modulator of the gut microbiome and a critical factor in both gut and skin health. Dietary fibers—fermented by gut microbes into anti-inflammatory SCFAs—as well as polyphenols and carotenoids like beta-carotene, have been shown to reduce skin inflammation and strengthen the skin barrier (Mahmud et al., 2022; Menke et al., 2013; Richelle et al., 2006).
While the science is still emerging, current findings appear to reaffirm an old truth: a healthy, plant-rich diet high in fibers, polyphenols, and probiotics is likely to benefit not only gut health, but also the skin.
References:
Bibb RHL. Chronic Intestinal Auto-Intoxication. Tex Med J (Austin). 1908 Mar;23(9):348-352. PMID: 36956350; PMCID: PMC9626160.
De Almeida, C.V.; Antiga, E.; Lulli, M. Oral and Topical Probiotics and Postbiotics in Skincare and Dermatological Therapy: A Concise Review. Microorganisms 2023, 11, 1420. https://doi.org/10.3390/microorganisms11061420
Jimenez-Sanchez, M., Celiberto, L. S., Yang, H., Sham, H. P., & Vallance, B. A. (2025). The gut-skin axis: a bi-directional, microbiota-driven relationship with therapeutic potential. Gut Microbes, 17(1). https://doi.org/10.1080/19490976.2025.2473524
Mahmud, Md. R., Akter, S., Tamanna, S. K., Mazumder, L., Esti, I. Z., Banerjee, S., … Pirttilä, A. M. (2022). Impact of gut microbiome on skin health: gut-skin axis observed through the lenses of therapeutics and skin diseases. Gut Microbes, 14(1). https://doi.org/10.1080/19490976.2022.2096995
Meinke MC, Friedrich A, Tscherch K, Haag SF, Darvin ME, Vollert H, Groth N, Lademann J, Rohn S. Influence of dietary carotenoids on radical scavenging capacity of the skin and skin lipids. Eur J Pharm Biopharm. 2013 Jun;84(2):365-73. doi: 10.1016/j.ejpb.2012.11.012. Epub 2012 Dec 13. PMID: 23246796.
Richelle M, Sabatier M, Steiling H, Williamson G. Skin bioavailability of dietary vitamin E, carotenoids, polyphenols, vitamin C, zinc and selenium. Br J Nutr. 2006 Aug;96(2):227-38. doi: 10.1079/bjn20061817. PMID: 16923215.
La Mode illustrée 1 janvier 1908 - (1-janvier-1908) | RetroNews - Le site de presse de la BnF
