Dietary Modifications Don’t Live Up to Hype
“Food continues to be one of the most discussed aspects of atopic dermatitis,” Peter Lio, MD, clinical assistant professor of dermatology and pediatrics at Northwestern University Feinberg School of Medicine, Chicago, Illinois, said in an interview.
“Almost all of my patients and families ask about dietary modifications, even though almost all of them have experimented with it to some degree,” said Lio. In his experience, diet plays a small role, if any, in the day-to-day management of atopic dermatitis.
This lack of effect of dietary changes is often frustrating to patients because of the persistent “common wisdom” that points to diet as a root cause of atopic dermatitis, Lio said. “Many practitioners continue to recommend excluding foods such as gluten or dairy from the diet, but generally these are only of modest help,” and although patients wish that dietary changes would fix the problem, most are left wondering why these changes didn’t help them.
The current study findings “reflect my own experience after nearly 20 years of being deeply immersed in the world of atopic dermatitis,” Lio said. Although the takeaway message does not argue against eating healthy foods, some foods do seem to make AD worse in some patients and may have nonallergic pro-inflammatory effects.
“In those cases, it is reasonable to limit or avoid those foods. However, it is extremely difficult to tell what food or foods are driving flare-ups when things are out of control, so dietary modification is generally not the best place to start,” he said.
True food allergies are much more common in patients with atopic dermatitis compared with individuals without atopic dermatitis, but the current study is not addressing these types of allergies, Lio emphasized. “If someone has true allergy to peanuts, for example, they should not be eating them; we also know that they are not ‘cheating’ because these patients would not merely have an eczema flare; they would have urticaria, angioedema, or anaphylaxis. There is tremendous confusion around this point and lots of confusion around allergy testing and its limitations.”
In addition, patients with atopic dermatitis are more likely than those without atopic dermatitis to have abnormalities in the gut microbiome and gut barrier, Lio said.
Abnormalities in the gut microbiome are different from the concept of allergy and may fall into the more complex category of barrier and microbiome disruptors, he said. Therefore, “the food category may not be nearly as important as the specific preparation of the food along with the additives (such as preservatives and emulsifiers) that may actually be driving the problem.”
Although in the past many clinicians advised patients to try cutting out certain foods to see whether atopic dermatitis symptoms improved, this strategy is not without risk, said Lio. “There have been incredible advancements in understanding the role of the gut in tolerization to foods.” Recent research has shown that by eating foods regularly, particularly those such as peanuts that seem to have more allergic potential, the body becomes tolerant, and this prevents the development of true food allergies.
As for additional research, many questions remain about the effects of types of foods, processing methods, and timing of introduction of foods on atopic dermatitis, Lio noted.
“Atopic dermatitis is a systemic condition with the immune system, with the skin/gut/respiratory barriers and microbiome involved; I think we now have a broader view of how big and complex the landscape really is,” he said.
The study received no outside funding. The researchers had no financial conflicts to disclose. Lio had no disclosures relevant to elimination diets but disclosed serving on the speakers bureau for AbbVie, Arcutis Biotherapeutics, Eli Lilly, Galderma, Hyphens Pharma, Incyte, La Roche–Posay/L’Oréal, Pfizer, Pierre Fabre Dermatologie, Regeneron/Sanofi Genzyme, and Verrica Pharmaceuticals; serving on consulting/advisory boards; or having stock options for many pharmaceutical companies. Lio also disclosed a patent pending for a Theraplex product with royalties paid and is a board member and Scientific Advisory Committee member emeritus of the National Eczema Association.
A version of this article first appeared on Medscape.com.