Acne vulgaris
Acne vulgaris might be greatly influenced by our gut microbiome and what we eat. People with acne seem to have less Clostridium, Clostridiales, Lachnospiraceae or Ruminococcaceae compared to people who don’t have acne. The microbiomes of those with acne have also been shown to have fewer Firmicutes and more Bacteroides and a reduced variety of bacterial species in general. High-fat diets containing large amounts of saturated fats have been linked to acne. Some studies also show a link between insulin resistance (how well our bodies process sugar) and acne. So, if you have acne, working with a dietitian alongside your dermatologist might be helpful.
Atopic dermatitis
Atopic dermatitis, also known as eczema, is associated with an imbalance of bacteria in the gut and skin. For example, Staphylococcus aureus, a pro-inflammatory bacteria, was isolated from more people with atopic dermatitis compared to the people without. In terms of the gut microbiome, those with eczema may have lower levels of beneficial Bifidobacterium and butyrate-producing bacteria. Bifidobacteria are common in infants and help to train the immune system. Butyrate is a short-chain fatty acid that also helps to reduce inflammation in the gut. It is produced by certain bacteria, such as Faecilabacteirum prausnitzii and Akkermansia. They also influence the production of Treg cells by the immune system, which plays a role in allergy and atopy. As with acne, diet can also undoubtedly play a role in atopic dermatitis, with fruits, vegetables and omega-3 fatty acids from foods such as oily fish and walnuts showing protection against and preventing the risk of developing atopic dermatitis.
Psoriasis
Psoriasis is an inflammatory skin condition with autoimmune elements. Two separate studies found a link between higher numbers of Firmicutes and lower numbers of Bacteroidetes in the gut microbiome in people with psoriasis. People with psoriasis appear to be at greater risk for developing other autoimmune conditions, such as celiac disease. With celiac disease, ingestion of gluten causes immune cells to attack villi, the cells in the gut responsible for absorbing nutrients. Two small clinical trials showed improvement in psoriasis markers following a gluten-free diet.
Rosacea
Rosacea is another common skin disorder characterised by red patches on the face and neck. It may be brought about by exercise, alcohol, and spicy foods, but it is strongly linked to gut health. Rosacea has been associated with an overgrowth of bacteria in the small intestine, also known as SIBO, and with Helicobacter pylori (H. Pylori) infection. Eradicating these bacteria with antibiotics has been shown to improve rosacea lesions.
