The Gut–Skin Axis
Your gut microbiome and your skin are in constant communication. Here is what the research says about probiotics, prebiotics, and skin conditions.
The gut–skin axis refers to the bidirectional communication between your gut microbiome — the trillions of bacteria, fungi, and other microorganisms in your digestive tract — and your skin. It operates through immune signalling, the production of short-chain fatty acids, systemic inflammation, and hormonal pathways. The science is still developing, but several connections are now well-supported.
What is established
- People with eczema (atopic dermatitis) have measurably different gut microbiome compositions to those without it. Dysbiosis (an imbalanced microbiome) is associated with increased intestinal permeability and systemic inflammation that worsens eczema.
- Rosacea is associated with gut conditions including SIBO (small intestinal bacterial overgrowth) in some studies. Treating SIBO has produced skin improvement in small trials — causation is not confirmed, but the overlap is notable.
- Acne: altered gut microbiome diversity is observed in acne patients in observational studies, though whether this is a cause or effect is unclear.
- Probiotics: a 2021 meta-analysis found that oral probiotic supplementation reduced acne lesion counts, though study quality varied. Lactobacillus and Bifidobacterium strains are the most studied.
Practical steps
- Eat a diverse range of plant foods — fibre variety is the strongest predictor of microbiome diversity.
- Include fermented foods (yoghurt, kefir, sauerkraut, kimchi, kombucha) — these contain live bacteria shown in RCTs to improve microbiome diversity.
- Limit ultra-processed foods — these reduce microbial diversity and increase inflammatory markers.
- Avoid unnecessary antibiotics — they cause significant, sometimes lasting, disruption to the gut microbiome.
Frequently asked
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