Studies show promise
Many patients with psoriasis and psoriatic arthritis who are looking for treatments that don't involve drugs are interested in gluten-free diets. They wonder if these diets will improve their condition.
Gluten is a complex protein found in wheat, barley and rye. It causes problems for people who have celiac disease, a condition that damages the intestine, and for people who are allergic or sensitive to gluten.
Because the inflammation associated with these conditions is similar to the inflammation caused by psoriasis, some studies have examined the role a gluten-free diet might play in treating psoriasis. The findings are not clear-cut, but they do show some promise.
It is estimated that up to 25 percent of people who have psoriasis also are sensitive to gluten. Gluten sensitivity can be identified by the presence of substances in the blood called anti-gliadin (AGA) and anti-endomysial (AEA) antibodies. Recent studies measured AGA levels in patients with psoriasis. For example:
- In a Swedish study comparing 302 patients who had psoriasis with patients who did not have the disease, 8 percent of the psoriasis group had elevated AGA levels, compared with 3 percent of the nonpsoriasis group.
- A Polish study revealed elevated AGA in 15 percent of participants who had severe psoriasis, compared with 6 percent in the nonpsoriasis group.
- By contrast, studies conducted in the U.S. and in Kashmir showed no elevation in AGA levels in people who had mild to moderate psoriasis, compared with people who did not have the disease.
Though these studies are not conclusive, they do indicate that gluten may play a role in psoriasis. More and larger studies are needed to definitively link gluten sensitivity and psoriasis. Meanwhile, screening patients with moderate to severe psoriasis for the AGA antibody may be helpful in finding out whether they are sensitive to gluten.
Do gluten-free diets help?
Other studies have tried to determine if gluten-free diets improved psoriasis. One study tracked 33 patients who had psoriasis and elevated AGA levels and who followed a gluten-free diet for three months. Of that group, 73 percent experienced a nearly 50 percent improvement in their psoriasis. Once these patients returned to their original diets, their psoriasis rebounded to its previous severity. Again, more clinical trials with larger numbers of patients would help determine if gluten-free diets are useful.
While gluten-free diets will not clear everyone's psoriasis, they do have a good chance of significantly reducing the psoriasis of people who test positive for the AGA antibody. Because the AGA tests often produce false negative results—that is, they indicate the antibody is not present, but, actually, the antibody is present—people who don't test positive for AGA still might find a gluten-free diet worth trying.
Although a gluten-free diet can be difficult to follow, studies do not show any adverse events from trying it. There are no risks of suppressing the immune system or developing infections or liver or bone marrow toxicity.
On the contrary, if someone's skin improves as the result of a gluten-free diet, it is likely that other aspects of that person's health may improve when their digestive system starts working properly and absorbing more nutrients.