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 line of communication running via the immune system. Multiple reviews show an association between disruptions to the bacterial balance in the gut (dysbiosis) and skin conditions such as psoriasis, atopic eczema, acne, rosacea and hair loss. That association is plausible, but in most cases it has not yet been established as a proven cause-and-effect relationship. The underlying mechanisms have also not yet been fully clarified.

Oral probiotics are being investigated as a way to influence the skin via the gut, possibly by dampening inflammation and steering the immune system. However, the available evidence is limited and applies to specific patient groups. Which bacterial strains help most, for which skin complaint and at which dosage, remains insufficiently clear to serve as a basis for broad recommendations.

Diet can influence the composition of your gut bacteria and thereby affect the skin indirectly. Prebiotics (fibres that feed bacteria) play a role in this. But the same caveat applies here: concrete, science-based recommendations specifically for skin health do not yet exist.

There is one notably specific finding from melanoma research: patients with a greater diversity of gut bacteria responded better to a particular form of immunotherapy for skin cancer. That is relevant for skin oncology, but has no direct bearing on everyday skin care.

A complicating factor is that every healthy person already differs enormously in the composition of their gut microbiome. Ethnic background, diet and early exposure to bacteria all play a part. This makes it difficult to say what a 'healthy' microbiome for the skin actually looks like, let alone how to achieve it in a targeted way.