Does a healthy gut microbiome lead to better skin?

Gut bacteria and the skin are connected through what researchers call the gut-skin axis: a pathway involving the immune system and metabolic byproducts through which gut bacteria exert influence on the skin. Disruptions in the gut microbiome (too little diversity or an unhealthy bacterial mix) are linked in multiple reviews to skin conditions such as eczema, psoriasis, acne and rosacea. Cause and effect have not yet been definitively proven in humans, but the association has been described for all of these conditions.

Oral probiotics and prebiotics are being investigated as a way to improve skin complaints by acting on the gut. Early research shows possible benefits for eczema and acne in certain patient groups. However, large, well-designed clinical studies are still lacking, so firm conclusions about which probiotic strain works best for which complaint cannot yet be made.

A particularly well-studied association is the one between gut flora and the response to immunotherapy in skin cancer (melanoma). Patients with a more diverse gut flora and more bacteria from the Ruminococcaceae family responded significantly more often to immunotherapy. This was an observational study involving 112 patients, supplemented by animal research. It is therefore not yet a recommendation, but it does show that the influence of the gut microbiome extends beyond superficial skin complaints.

An important point to be aware of: there is no universal 'ideal' gut microbiome. The Human Microbiome Project demonstrated that the bacterial mix differs considerably among healthy individuals, depending on diet, heredity, environment and early exposure to microbes. What is healthy for your gut therefore differs from what is healthy for someone else's.

For practical purposes this means: there is preliminary evidence that a diverse, balanced gut flora is beneficial for your skin, and that probiotics may help with specific skin complaints. However, which probiotics, at which dose and for which condition have the greatest effect remains unclear. Diet, variety in plant-based foods and dietary fibre are currently the most logical and lowest-risk way to support your gut flora.