Many chronic skin conditions have a digestive component, which is why treating the skin from the outside alone so often isn’t enough for long-term results.
The gut and the skin are in constant communication through the immune system, the microbiome, and systemic inflammation, a relationship researchers call the gut-skin axis. When the gut is inflamed, imbalanced, or not absorbing nutrients well, the skin is frequently where that shows up.
This is one of the more actively researched areas in dermatology, and it explains a pattern we see constantly in clinic: someone has tried every topical, cut out every “trigger” food they read about online, and still experiences flares, because the driver was beyond the surface of their skin.
Here is how the connection works, which conditions it applies to, and what we may investigate in clinic.
How the gut and skin talk to each other
Roughly seventy percent of the immune system sits in and around the gut. The community of microbes living there help to train and regulate your immune system. The skin has its own microbiome and immune activity, and the two systems are linked closely enough that a disturbance in one is often reflected in the other.
There are several mechanisms behind this.
- Intestinal permeability, sometimes called “leaky gut”. When the tight junctions between the cells lining the gut become compromised, bacterial fragments and partially digested particles can pass into the bloodstream. The immune system responds, and the resulting low-grade systemic inflammation can surface in the skin.
- The microbiome itself. A less diverse or imbalanced gut microbiome, a state called dysbiosis, is associated with several inflammatory skin conditions. When fibre-fermenting bacteria are underrepresented, the gut produces fewer short-chain fatty acids, which are among the body’s most important anti-inflammatory compounds.
- Nutrient absorption. Skin barrier integrity and repair depend on zinc, vitamin A, essential fatty acids, and vitamin D, among others. If digestion or absorption is compromised, you can eat well and still be functionally short of what the skin needs.
- The gut-brain-skin axis. Stress alters gut motility and the microbiome, which in turn influences inflammation and skin behaviour. This is part of why so many people notice their skin worsens or flares during or after high-stress periods.
The conditions where the link is strongest
Rosacea
People with rosacea have been found to have a markedly higher prevalence of small intestinal bacterial overgrowth, or SIBO. In several studies, addressing the overgrowth was associated with significant improvement in the skin, in some cases lasting well beyond the intervention.
Acne
Dysbiosis and intestinal permeability are more common in people with acne, and the condition is closely tied to insulin signalling, which is itself shaped by diet and metabolic health.
This helps explain why blood sugar regulation and gut function tend to move acne when topical treatment alone plateaus. It also explains why the relationship with dairy and high-glycaemic foods is real for some people and irrelevant for others. The response depends on the individual’s metabolic and gut picture, not on a universal “acne food” list.
Eczema and atopic dermatitis
The composition of the gut microbiome in infancy is associated with the later development of eczema, and reduced microbial diversity is a recurring finding. In adults, gut inflammation and food sensitivities can contribute to the inflammatory load that keeps eczema active.
Eczema is rarely driven by a single cause, which is exactly why a barrier cream can soothe it without ever resolving it.
Psoriasis
Psoriasis is an autoimmune condition, and it shares meaningful ground with inflammatory bowel disease. The two conditions co-occur more often than chance would predict, and both involve disrupted gut barrier function and immune dysregulation. Psoriasis needs medical management, and the gut work sits alongside that rather than replacing it.
Why topical-only approaches so often aren’t enough
Topical treatment addresses what is happening at the skin’s surface. It can be extremely useful for supporting a healthy skin barrier, and for some conditions it is essential. What it cannot do is change the internal environment producing the flare in the first place.
If the driver is systemic inflammation from a compromised gut barrier, an imbalanced microbiome, or poor nutrient status, then treating the surface is managing the output while the input continues. The skin improves, then relapses, and the cycle repeats. This is the pattern that brings most people to look deeper, usually after months or years of surface treatment that never quite holds.
Treating the gut is not a replacement for appropriate dermatological or medical care. It is the part of the picture that surface treatment cannot reach, and for many people it is the missing piece.
What we investigate
Rather than guessing, we look for the specific drivers relevant to your presentation. Depending on the picture, that can include comprehensive stool and microbiome testing to assess diversity, inflammatory markers, and dysbiosis, breath testing where SIBO is suspected, and assessment of nutrient status for the vitamins and minerals the skin barrier depends on.
We also look at the things that quietly shape gut function and rarely make it onto a symptom list: stress load, sleep, blood sugar regulation, and medication use. The aim is to identify what is actually driving your skin rather than applying a generic gut protocol and hoping.
Supporting your gut and skin, practically
Some foundations help almost everyone, regardless of the specific condition.
- Eat a wide variety of plants, aiming for diversity across the week rather than the same few vegetables, since microbiome diversity tracks with dietary diversity.
- Include fibre-rich and fermented foods where they are tolerated, which support short-chain fatty acid production
- Include oily fish, walnuts, or ground linseed regularly for the essential fatty acids that support the skin barrier
- Steady your blood sugar by pairing carbohydrates with protein and healthy fat rather than eating them alone
- Address stress deliberately, since the gut-brain-skin loop is real and stress management measurably influences it
- Be cautious with restrictive elimination diets undertaken alone, which can worsen microbiome diversity and rarely identify the true driver
*Note: Those struggling with gut issues, such as SIBO/dysbiosis, may find that they do not tolerate plant fibres and fermented foods very well. In this case, please reach out to work with a practitioner so that we can address healing the gut first.
Written by Alyssa Wisniewski, BHSc (Naturopathy), AFMCP, functional naturopath at Wellness Vision, Wallsend.
This article is general information and is not individual health advice. Book a free discovery call to discuss how we can work with you.