There are two important reasons for physicians to address the role of diet when managing psoriasis patients. One is to limit risks of cardiovascular and metabolic comorbidities. The other is to potentially improve psoriasis severity.
Evidence suggests certain food types can flare psoriasis and losing weight can improve treatment response for some with psoriasis, according to Rajani Katta, M.D., co-author of an article that examines how dietary changes can impact skin diseases ― including psoriasis, published earlier this year in Skin Therapy Letter.
“We know that patients who have psoriasis are at higher risk for diabetes, high blood pressure, heart disease and a number of metabolic abnormalities. It’s really important that psoriasis patients know that and realize that changing their diet can be an important part of preventing these comorbidities,” said Dr. Katta, a dermatologist with Texas Children’s Hospital in Houston.
Smoking and high alcohol intake are recognized psoriasis triggers, however, dietary factors may also play a role, she said.
The question about whether what patients eat could make their psoriasis worse needs more research, but there are evidence-based suggestions dermatologists can make about certain food types.
“One that has been researched more extensively is the role of gluten,” Dr. Katta says.
Psoriasis patients are bound to ask about gluten because gluten’s role is mentioned extensively and high up on Google searches on diet and psoriasis.
“The gist of it is that gluten-containing foods can act as a trigger in a small percentage of patients, but definitely not all,” she said.
Dr. Katta says an important clue about whether to pursue gluten as a trigger is to ask psoriasis patients about gastrointestinal symptoms, such as abdominal pain, diarrhea, or of evidence of certain nutrient deficiencies, including iron deficiency.
“Those are clues that they may have celiac disease,” she said.
Dr. Katta refers those psoriasis patients to gastroenterology for a workup, and she might order a test for antibodies to gluten.
“There was one large study that found there was about a two-fold higher risk of celiac disease in patients with psoriasis,” Dr. Katta says. “There’s not a high risk of celiac disease baseline, so even a two-fold higher risk is not a huge number, but it’s definitely an increased risk and that’s why we take it seriously when psoriasis patients have gastrointestinal symptoms.”
Researchers have also found patients who have antibodies to gliadin in their bloodstream, but do not have celiac disease, fare better on psoriasis treatment when they’re on a gluten-free diet than matched controls.
APPLYING KNOWLEDGE TO PRACTICE
Physicians should ask psoriasis patients about gastrointestinal symptoms. It’s an easy screening tool for better managing those patients, Dr. Katta said.
Physicians who take patients’ height, weight and blood pressure during office visits, should calculate body mass index (BMI) and consider referring patients who are overweight or obese to a nutritionist. Dermatologists can tackle the touchy subject with their patients by mentioning their higher risk of comorbidities. They should also mention that there is evidence to suggest that weight loss can improve psoriasis patients’ treatment response, reflected by improved psoriasis area and severity index, or PASI, scores.
Providers can direct patients to the review published July 2014 in the Journal of the American Academy of Dermatology (JAAD) in which authors concluded that a number of studies have shown weight loss may be a preventative and adjunctive therapy for psoriasis or psoriatic arthritis treatment in patients who are overweight or obese.
“Given the vast body of popular literature available to patients, it is important for clinical providers to familiarize themselves with the evidence supporting various dietary plans. By doing so, they will be able to engage their patients and partner with them to maximize the impact of pharmacologic and non-pharmacologic interventions,” the JAAD authors write.
Dr. Katta is author of the book Glow: The Dermatologist’s Guide to a Whole Foods Younger Skin Diet.
Katta R, Kramer MJ. Skin and Diet: An Update on the Role of Dietary Change as a Treatment Strategy for Skin Disease. Skin Therapy Letter. 2018 Jan;23(1):1-5.
Michaëlsson G, Gerdén B, Hagforsen E, Nilsson B, Pihl-Lundin I, Kraaz W, Hjelmquist G, Lööf L. Psoriasis patients with antibodies to gliadin can be improved by a gluten-free diet. British Journal of Dermatology. 2000 Jan;142(1):44-51.
Debbaneh M, Millsop JW, Bhatia BK, Koo J, Liao W. Diet and Psoriasis: Part I. Impact of Weight Loss Interventions. Journal of the American Academy of Dermatology. 2014;71(1):133-140. doi:10.1016/j.jaad.2014.02.012.