Gluten is the name for a group of proteins (called glutenins and gliadins) found in wheat, rye and barley. A strict gluten free diet involves avoiding all foods made with these cereals (including bread, pasta, biscuits, pastry, crackers, and snack foods) and foods with trace amounts of gluten, like soya sauce.
DairyIn the UK, gluten free diets are normally only recommended for coeliac disease, a condition where gluten triggers the immune system to mistakenly attack the small intestine, causing inflammation and damage to the lining of the gut.
However, new research suggests a gluten free diet may be helpful in other autoimmune diseases like psoriasis, and in non-coeliac gluten sensitivity, where various symptoms (including skin conditions1) improve on a gluten free diet, in spite of there being no damage to the lining of the gut.2 3
What do we know about gluten free diets and psoriasis?
Coeliac disease is around twice as common in people with psoriasis compared to the general population4 5 6. Patients with psoriasis are also more likely to have raised levels of the antibodies (special immune cells) and genes associated with coeliac disease and non-coeliac gluten sensitivity (NCGS)7 8 9 than control groups.
Researchers don’t fully understand how coeliac disease, psoriasis and gluten are linked but we know that both diseases involve the immune system and share similar genetic and inflammatory pathways. It has been suggested that gluten may affect the lining of the gut, allowing the passage of antigens that trigger an overactive immune response12.
In one Swedish study, psoriasis patients with raised coeliac antibodies experienced significant improvements in their psoriasis severity after following a gluten free diet for three months, which deteriorated when they returned to their normal diet13. In psoriasis patients who are diagnosed with coeliac disease, adopting a gluten free diet can improve skin lesions and in some cases, clear the condition altogether14.
More recently a study of patients with NCGS and skin conditions similar to eczema and psoriasis found significant improvements after one month on a gluten free diet. 15
There are no side effects to following a gluten free diet if it is well balanced. Studies have shown that patients following gluten-free diets long term have lower levels B vitamins, iron, calcium and fiber, which may in part be related to lower intakes of starchy foods like bread and pasta.
Should I follow a gluten free diet?
It’s not completely clear which patients with psoriasis should follow a gluten-free diet, but research suggests those with raised coeliac antibodies are most likely to benefit.
Because coeliac disease is also more common in psoriasis and may go undiagnosed, it’s worth getting a blood test to rule out the condition. However, you must have been consuming foods containing gluten in the 6 weeks before the blood test in order for it to be valid.
- Gluten is a protein found in wheat rye and barley that triggers coeliac disease, an autoimmune disease which damages the lining of the gut.
- Coeliac disease and markers of gluten sensitivity are more common in people with psoriasis.
- A gluten free diet may improve psoriasis severity in patients with raised antibodies or confirmed coeliac disease.
What the dietician says
No large research studies exist to show us how effective gluten free diets are in psoriasis overall, but for people with raised coeliac antibodies a gluten free diet may be beneficial, although the exact reasons aren’t clear. For those with coeliac disease and psoriasis a strict gluten free diet is essential.
A gluten free diet is a cost effective treatment that doesn’t have any known side effects, and therefore you may wish to trial it for a period of up to three months to see if you experience any improvements. However, it’s likely to be a big adjustment, particularly if you eat a lot of wheat-based products like breakfast cereal, bread and pasta, so it’s important to plan the diet properly to avoid nutrient deficiencies and a reliance on processed foods that may aggravate psoriasis because of high levels of sugar and vegetable oils. One of the key mistakes people make is not replacing the foods they exclude, which leaves the diet limited and lacking in fibre. It’s also important to become a label expert, as gluten is a trace ingredient in lots of foods you wouldn’t expect such as ice cream, salad dressing and sauces.
In the UK, The Coealic Society has downloadable resources and shopping lists that can help you plan a gluten free diet. If you decide to trial a gluten free diet, focus on naturally gluten free foods such as fruits, vegetables, fish, nuts, beans and pulses, poultry, eggs, and dairy, and replace wheat, barley and rye with quinoa, rice, potatoes, buckwheat, sorghum and teff.