Leaky Gut, Leaky Skin

The connection between gut health and skin health

We often hear about the importance of maintaining a healthy gut microbiome but what about the skin microbiome?  Like the gut, the skin hosts a diverse microbial ecosystem that plays a vital role in maintaining skin function.  Covering over 2 square meters and housing more than 1.5 trillion microbes across 900 species, our skin is more than just a physical barrier it’s a complex, living organ.1

The skin microbiome

The skin microbiome is composed of bacteria, fungi, viruses and other microorganisms that form a crucial layer of defence, support immune responses and aid in wound healing.  They can be grouped into:

• Resident microbes, which are stable long-term inhabitants and protect against harmful pathogens.
• Transient microbes, which come and go and may either benefit or harm the skin’s microbial balance.

Different skin regions support different microbial profiles, for example oily areas like the face have less microbial diversity, while drier areas like the limbs host a broader range of species.1

The gut-skin axis

The gut-skin axis refers to the bidirectional communication between the gastrointestinal system and the skin, mediated by the immune system, metabolites and microbial signalling.  When the microbiome in either the gut or the skin becomes imbalanced it can disrupt this communication and impair immune function.  Since a large portion of the body's immune system resides in the gut, disturbances here can have far-reaching effects, including the development of inflammatory or autoimmune skin conditions.2

A recent study by Feng et al. (2024) provided compelling evidence of a causal relationship between gut microbial composition and immune-mediated skin disorders, particularly psoriasis.  The researchers identified that an overabundance of Eubacterium fissicatena significantly increased the risk of developing psoriasis.3
One key mechanism linking gut health to skin function involves short-chain fatty acids (SCFAs), such as butyrate, which are produced through the fermentation of dietary fibre by gut bacteria. SCFAs help reinforce the integrity of the gut barrier, reduce systemic inflammation and regulate immune responses by suppressing pro-inflammatory cytokines. 4

The immune system also has a role to play, due to the strong correlation between overactive T-helper 2 cells present in immune dysregulation and inflammation of the gut and skin.  This type of immune imbalance has been implicated in conditions like atopic dermatitis and inflammatory bowel disease. 1,5

Factors that affect the skin microbiome

Stress, sleep quality, exercise and environmental toxins all influence gut and skin health.  For instance, chronic stress raises cortisol levels, which impairs gut barrier function and increases inflammation contributing to both leaky gut and leaky skin.6

• Age: As we age, environmental exposure reduced hydration and slower skin regeneration alter the microbial balance.1
• Sex: Hormonal changes during puberty, pregnancy or menopause affect sebum levels and microbial composition.
• Genetics: This influence’s how your immune system interacts with skin microbes. 5
• Environment: Pollution, UV exposure, humidity and altitude all impact the skin’s microbial health.  When the microbial balance on the skin breaks down, the skin barrier becomes compromised leading to immune overactivity, inflammation and a self-perpetuating cycle of skin dysfunction.7
• Cosmetics: Harsh skincare products or over-cleansing can disrupt the natural microbial balance.1
• Diet: A diet high in fibre, antioxidants and healthy fats supports both gut and skin microbiota.4

Skin conditions linked to microbial imbalances

Eczema (Atopic Dermatitis): Triggered by overgrowth of Staphylococcus aureus and reduced microbial diversity.  Infants with low gut Bacteroides levels are also more likely to develop eczema. 8,9

Psoriasis: Linked to decreased microbial diversity and increased Streptococcus, Corynebacterium and Staphylococcus species on the skin.  Gut dysbiosis, particularly involving Eubacterium fissicatena also plays a role. 3

Acne: Associated with overgrowth of Cutibacterium acnes, leading to inflammation and clogged follicles.1

Herbal skin support

Herbs can play a significant role in supporting skin health by targeting the gut, immune system, detoxification pathways and the skin itself through topical application. Herbal medicine can help strengthen the skin barrier, reduce inflammation and promote skin integrity from the inside out. 

Herbs to support the gut-skin axis: Herbs that support the gut include Marshmallow root (Althaea officinalis), Slippery elm (Ulmus rubra), Aloe vera (Aloe barbadensis), Liquorice root (Glycyrrhiza glabra), Ginger (Zingiber officinale), Kawakawa (Macropiper excelsum) and Peppermint (Mentha x piperita). These herbs are soothing and help repair the intestinal lining helping to reduce inflammation and reduce intestinal permeability. 

Herbs to support the immune system: Herbs that support immune function can help regulate immune responses, enhance resilience and reduce inflammation that contributes to skin disorders such as eczema, acne or psoriasis. Echinacea (Echinacea purpurea) helps modulate immune activity and reduce inflammation. It has been clinically shown to be an effective acne treatment when used internally, due to its anti-inflammatory, antioxidant, and antimicrobial actions. 10  Andrographis (Andrographis paniculata), is a bitter herb known for its potent anti-inflammatory and antimicrobial properties.  

Herbs that support detoxification: Herbs that support detoxification can help clear internal waste and reduce the burden on the skin.  Dandelion (Taraxacum officinale) and Milk Thistle (Silybum marianum) support liver function and bile flow, promoting the elimination of metabolic waste.  Globe artichoke (Cynara scolymus) enhances digestive and hepatic activity, while Cleavers (Galium aparine) and Nettle (Urtica dioica) help to support lymphatic drainage and kidney filtration.  Ginger (Zingiber officinale) adds circulatory support, ensuring efficient delivery and clearance of nutrients and waste throughout the body. 

Topical herbs for the skin: These herbs can be used in the form of creams, oils, salves or compresses to soothe irritation and enhance skin repair.  Calendula (Calendula officinalis) is a well-known skin-healing herb, promoting tissue regeneration and reducing inflammation.  Kawakawa (Macropiper excelsum) has traditional uses in Māori medicine and offers antimicrobial and anti-inflammatory benefits.  Liquorice (Glycyrrhiza glabra) can be used topically to calm redness and irritation, especially in sensitive or reactive skin. Additional topical herbs include Chamomile (Matricaria recutita) for its calming and anti-inflammatory effects, Gotu kola (Centella asiatica) for enhancing collagen synthesis and wound healing, and Comfrey (Symphytum officinale) for supporting tissue repair and reducing scarring. These herbs provide targeted support for maintaining the skin's barrier function and promoting a healthy, balanced skin.

Supporting a Healthy Skin Microbiome

• Hydration: Helps support the skin’s barrier and its resident microbes.
• Gentle Skincare: Avoid over-cleansing or using antimicrobial-heavy products.
• Probiotic/Prebiotic Nutrition: SCFAs like butyrate help maintain gut and skin health. 4
• Stress Management: Practices like yoga or meditation can help rebalance immune and microbiome health. 6
• Exercise: Promotes gut microbial diversity and reduces intestinal permeability. 6
• Pollution Protection: Minimizing exposure to toxins supports microbiome stability.
  

 

References:

1. Ryguła, I., Pikiewicz, W., Grabarek, B. O., Wójcik, M., & Kaminiów, K. (2024). The role of the gut microbiome and microbial dysbiosis in common skin diseases. International Journal of Molecular Sciences, 25(4), 1984. https://pubmed.ncbi.nlm.nih.gov/38443417/
2. Jiao, Y., Wu, L., Huntington, N. D., & Zhang, X. (2020). Crosstalk between gut microbiota and innate immunity and its implication in autoimmune diseases. Frontiers in Immunology, 11, 282. https://pubmed.ncbi.nlm.nih.gov/32231637/
3. Feng, F., Li, R., Tian, R., Wu, X., Zhang, N., & Nie, Z. (2024). The causal relationship between gut microbiota and immune skin diseases: A bidirectional Mendelian randomization. PLOS ONE, 19(3), e0298443. https://pubmed.ncbi.nlm.nih.gov/38420209/
4. Mann, E. A., Bae, E., Kostyuchek, D., Chung, H. J., & McGee, J. S. (2020). The gut microbiome: Human health and inflammatory skin diseases. Annals of Dermatology, 32(5), 440–446. https://pubmed.ncbi.nlm.nih.gov/33029590/
5. Coates, M., Lee, M. J., Norton, D., & MacLeod, A. S. (2019). The skin and intestinal microbiota and their specific innate immune systems. Frontiers in Immunology, 10, 2950. https://pubmed.ncbi.nlm.nih.gov/31921026/
6. Do, N. M. (2024). From leaky gut to leaky skin: A clinical review of lifestyle influences on the microbiome. American Journal of Lifestyle Medicine. Advance online publication. https://doi.org/10.1177/15598276241292605
7. Pessemier, B. D., Grine, L., Debaere, M., Maes, A., Paetzold, B., & Callewaert, C. (2021). Gut–skin axis: Current knowledge of the interrelationship between microbial dysbiosis and skin conditions. Microorganisms, 9(2), 353. https://pubmed.ncbi.nlm.nih.gov/33672841/
8. Abrahamsson, T. R., Jakobsson, H. E., Andersson, A. F., Björkstén, B., Engstrand, L., & Jenmalm, M. C. (2012). Low diversity of the gut microbiota in infants with atopic eczema. Journal of Allergy and Clinical Immunology, 129(2), 434–440. https://pubmed.ncbi.nlm.nih.gov/22082927/
9. Kong, H. H., Oh, J., Deming, C., Conlan, S., & Grice, E. A. (2012). Temporal shifts in the skin microbiome associated with disease flares and treatment in children with atopic dermatitis. Genome Research, 22(5), 850–859. https://pubmed.ncbi.nlm.nih.gov/22310444/
10. Rinaldi, F., Marotta, L., Mascolo, A., Amoruso, A., Pane, M., Giuliani, G., & Pinto, D. (2022). Facial acne: A Randomized, double-blind, placebo-controlled study on the clinical efficacy of a symbiotic dietary supplement. Dermatology and Therapy, 12(2), 577–589. https://doi.org/10.1007/s13555-021-00664-z