Does a healthy gut microbiome lead to better skin?
There are several indications that a healthy gut microbiome is beneficial for your skin, but how best to achieve that and which interventions truly work has not been sufficiently proven to recommend specific supplements or treatments.
Bacteria in your gut and the condition of your skin are connected through what researchers call the 'gut-skin axis'. Signals from gut bacteria reach the immune system and influence inflammatory processes that also play a role in the skin. Multiple reviews confirm this connection, although the exact mechanisms have not yet been fully worked out.
People with skin conditions such as eczema, psoriasis, acne and rosacea are more often found to have a disrupted gut microbiome than people without those complaints. But whether that disrupted gut microbiome causes the skin disease, or whether the skin disease (and everything that comes with it, such as medication use and stress) disrupts the gut microbiome, has not yet been clarified. This is an association, not a proven causal relationship.
Probiotics as a supplement show cautious improvements in smaller clinical studies for eczema, psoriasis and acne. They appear to dampen inflammatory responses and influence the immune system. The studies conducted so far are limited in size and focus on specific groups, so broad recommendations have not yet been made. Which probiotic strains have the greatest effect, and in whom exactly, is also not clear from the available literature.
There is also interest in probiotics and prebiotics for skin ageing, wrinkles and dryness, but the evidence here is even thinner. There are indications, not firm conclusions. One notable finding: exposure of the skin to sunlight (UVB) also appears to be able to influence the gut microbiome, meaning the connection runs in the other direction as well. This is a very early-stage area of research.
Faecal microbiota transplantation, in which gut bacteria from a healthy donor are transferred to a sick recipient, is also being investigated in early studies for skin complaints. Safety and effectiveness have not yet been sufficiently established for use outside a research setting. Simpler adjustments, such as a higher-fibre diet to support the gut microbiome, are also being studied but have not yet been researched thoroughly enough to base specific advice on.
All sources are reviews (no randomised trials or meta-analyses). The associations are plausible and consistently described, but the causal direction and optimal interventions have not yet been sufficiently established.
Can an unhealthy gut contribute to skin problems such as acne or eczema?
A disrupted gut microbiome is associated with acne and eczema, although that association has not yet been proven to be cause and effect. Eating more fibre and plant-based foods is a sensible first step; for targeted probiotics the evidence is still too mixed for a clear recommendation.
Does your gut microbiome affect how well you sleep?
Your gut microbiome influences your sleep through substances it sends to your brain, and poor sleep in turn disrupts your gut bacteria. A fibre-rich diet and a regular sleep and eating schedule are the best concrete steps you can take right now.
Can exercise improve your gut microbiome?
Moderate regular exercise demonstrably improves your gut microbiome, but you need to keep exercising because the effect disappears when you stop. Do not overdo it: very intensive training can actually put gut health under pressure.
Do probiotic pills actually help your gut?
Probiotics genuinely help, but not for everything and not equally with every pill. The evidence is strongest for antibiotic-associated diarrhoea and irritable bowel syndrome; for Crohn's disease, they demonstrably do not work.
Can you improve your gut microbiome by picking up bacteria while playing outside?
Playing outside exposes your child to more bacteria, and one small study observed a change in gut microbiome, but whether that is structurally beneficial for health has not yet been demonstrated. Diet, mode of birth, and medication use have a far stronger evidence base when it comes to shaping the gut microbiome.
Can you improve your gut bacteria by spending more time in nature?
Whether spending more time in nature improves your gut bacteria is a question the available studies cannot answer; if you want to positively influence your microbiome, diet and body weight have a far better documented effect.