The gut–lung axis
In plain language
With lung complaints we understandably look at the lungs themselves. Yet the gut also has a say. People with COPD or asthma often have a disrupted gut flora, and that dysbiosis can amplify the inflammation in the airways and worsen flare-ups. We see it after COVID too: persistent breathlessness, fatigue and a dysregulated autonomic nervous system, linked to a disrupted balance between microbiome and immune system. The explanation is that your gut flora produces inflammation-dampening substances that carry through to your lungs, and that it helps determine how strongly your immune defence responds to triggers and infections. Lung health is therefore partly a gut story — and that opens new ways to support recovery and resilience.
The science behind
Short-chain fatty acids (SCFAs) are the key metabolites of the gut–lung axis. They form during the fermentation of fibre and act anti-inflammatorily all the way to the airways; higher SCFA levels go hand in hand with better lung function and fewer COPD exacerbations. An impoverished microbiome means fewer of these protective substances — and therefore a higher inflammatory tone in the lungs.
Infection susceptibility and recovery also run via this axis. A disrupted balance between gut and lung flora increases the risk of resistant infections in chronic lung patients. In post-COVID, phenotypes show an immune-crosstalk imbalance that is partly influenceable via the gut, and in severe lung failure (ARDS) microbiome metabolites help steer the inflammatory cascade. Asthma, moreover, often turns out to go together with gut problems such as IBD, which points to a bidirectional crosstalk.
Why one person recovers smoothly and another stays stuck is co-metabolic: it depends on the interplay between genes, microbiome diversity, metabolites and lifestyle — not on a single factor. Genes colour the sensitivity, the whole determines the course. This reading is supportive and observational — not a medical diagnosis.
Illustration & CosmoTalks
Your body is not a collection of separate organs, but one cooperating whole — human and microbes.
- S1·E1 — Why you’re never alone: the human as an ecosystem
- S1·E2 — How your gut talks to your heart, liver and kidneys
- S1·E3 — Metabolites: the language between your organs
- S1·E4 — When the dialogue falters: dysbiosis and inflammation
- S1·E5 — Understanding one whole instead of separate complaints
Related concepts
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My InnerSelfie
Map the gut–lung axis: microbiome diversity and SCFA signals together with DNA and metabolites, translated into readable outcomes.
Discover My InnerSelfie →My Key Nutrients
Support your airways from within: fibre-rich, SCFA-friendly nutrition and formulas tailored to your co-metabolism.
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Discover CosmoPulse →The books · HOST · FORMULA · EDGE
The through-line of this science, from insight to everyday application, by Petra Van Gucht.
See the books →Scientific references
• Vlaming-van Eijk L., et al. (2025) — Immune crosstalk imbalance in post-COVID phenotypes. Wiley.
• Niculescu AG., et al. (2025) — Gut–lung dysbiosis and antibiotic resistance in chronic lung disease. Pathogens.
• Van Gucht P. — HOST (COSMO trilogy): why lung health is partly a gut story.
Frequently asked questions
- What is the gut–lung axis?
- The two-way dialogue between your gut and your lungs. The microbiome and short-chain fatty acids help influence inflammation, infection susceptibility and recovery.
- How can my gut influence my lungs?
- Mainly via short-chain fatty acids: anti-inflammatory substances from fibre fermentation that carry through to the airways and support lung function.
- Does the gut play a role in post-COVID?
- Research links persistent post-COVID complaints to a disrupted balance between microbiome and immune system, which is partly influenceable via the gut.
- Why do I recover more slowly than someone else?
- Because it depends on the interplay between genes, microbiome, metabolites and lifestyle. This is a supportive reading, not a diagnosis.
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