Adam Ford, BS, and April Armstrong, MD, MPH, on How Diet Affects Psoriatic Disease

Psoriasis affects an estimated 6.7 million adults, and approximately 10% to 20% of individuals with psoriasis will eventually develop psoriatic arthritis, according to the Centers for Disease Control and Prevention.1

Although psoriatic disease is most commonly treated with drugs, creams, and ointments, new research has suggested that diet may play an important role as well.

The Medical Board of the National Psoriasis Foundation issued dietary recommendations for patients with psoriasis and psoriatic arthritis following a systematic review of existing literature on the impact of diet on psoriatic disease.2

Consultant360 spoke with lead author Adam Ford, BS, research fellow at the Keck School of Medicine at the University of Southern California, and senior co-author April Armstrong, MD, MPH, associate dean of clinical research at the Keck School of Medicine, about the new recommendations.

Consultant360: Your article says that diet is rarely discussed during visits between clinicians and patients with psoriasis and/or psoriatic arthritis. Why do you think this is the case?

Adam Ford and April Armstrong: For a long time, our psoriasis patients have been asking us about the role of diet in psoriasis. Previously, there was a lack of evidence synthesis on the relationship between psoriasis and diet. As a result, clinicians were mostly unable to address their patients’ questions on the role of diet on psoriasis. This pivotal effort from the National Psoriasis Foundation has been a few years in the making and will provide clinicians with the data they need to discuss diet with their psoriasis patients.

C360: What consequences can occur in patients with psoriasis or psoriatic arthritis if diet is not properly addressed?

Authors: If diet is not properly addressed, then patients may not be achieving their best possible disease outcomes. For example, consider a patient with celiac disease and severe psoriasis. If diet is not properly addressed and the patient does not adhere to a gluten-free diet, he or she may not experience the level of improvement that could otherwise be achieved.

However, it is important to note that while certain diets can be helpful in select patients with psoriasis and/or psoriatic arthritis, it is the medical therapies that make the larger difference in reducing psoriasis overall.

C360: After completing your systematic review, you were able to strongly recommend dietary weight reduction with a hypocaloric diet in overweight and obese patients with psoriasis. How can adherence to this type of diet affect treatment outcomes?

Authors: We found that weight reduction with a diet low in calories is helpful in reducing psoriasis severity in overweight and obese psoriasis patients. This was true for patients on a variety of medical therapies for psoriasis including biologics, oral systemic therapies, phototherapy, and topical therapies. Therefore, adherence to a hypocaloric diet can lead to both weight loss and improved treatment outcomes in this patient population.

C360: What are the next steps in your research, especially in regard to the effects of a gluten-free diet and vitamin D supplementation in select subpopulations of adults with psoriatic disease?

Authors: There is a substantial need for additional research on the role of diet on psoriasis. Specifically, additional research is needed on the use of dietary supplements in psoriasis patients. For some supplements, there is too little evidence currently available in the scientific literature to make a recommendation, whereas for others, the evidence is conflicting.

With regard to gluten-free diet, additional research may help guide the development of guidelines for screening for gluten sensitivity in the psoriasis population. Additional studies are also needed in the area of dietary weight loss to determine whether it is the type of diet or the weight loss that leads to improvement in psoriasis. Finally, further research is needed on the role of specific foods, nutrients, and dietary patterns on psoriasis.

C360: Are there any educational gaps regarding diet and psoriatic disease that you believe need to be addressed?

Authors: Since there was a lack of evidence synthesis on the relationship between psoriasis and diet prior to this systematic review, these dietary recommendations from the National Psoriasis Foundation should help address educational gaps on this topic. We hope that clinicians will find these recommendations to be practical and that many psoriasis patients will benefit from their implementation.

For our coverage of the new recommendations issued by the Medical Board of the National Psoriasis Foundation, click here.

—Christina Vogt


  1. Psoriasis. Centers for Disease Control and Prevention. Page last updated on June 28, 2018. Accessed on July 9, 2018.
  2. Ford AR, Siegel M, Bagel J, et al. Dietary recommendations for adults with psoriasis or psoriatic arthritis from the Medical Board of the National Psoriasis Foundation: a systematic review [Published online June 20, 2018]. JAMA Dermatol. doi:10.1001/jamadermatol.2018.1412