Last year, a team of researchers from the Department of Dermatology at the faculty of medicine of the University of California-San Francisco (UCSF) published the results of a nationwide survey conducted to assess the impact of dietary choices on psoriasis.
More than 1200 members of the National Psoriasis Foundation answered the 61 questions in the survey, with results that were significant and at times surprising. The results of the survey give a clear idea of the dietary regimens most popular among patients, as well as of the foods that seem to cause an increase in the dermatological symptoms of psoriasis, and those which reduce them.
More than half of participants stated that reducing their consumption of alcohol, gluten and solanaceae – foods belonging to the family of vegetables that includes tomatoes, potatoes, aubergines (eggplant) and peppers – led to a clear improvement in symptoms. The addition of fish oil, vegetables and vitamin D also proved useful.
The participants also indicated that different dietary regimens were particularly effective at alleviating their symptoms: the Pagan diet (based on the principle that psoriasis is caused by a build-up of toxins, also known as “intestinal permeability”), the vegan diet, and the paleo diet. Gluten-free, Mediterranean, and vegetarian diets were identified as beneficial by participants.
Il Dr. John Y.M. Koo, director of the psoriasis, phototherapy and skin treatment clinic at the University of California-San Francisco, and co-author of the study, has noticed that the common factor linking this wide variety of diets is that all lead to weight loss.
Although there is not yet any effective data demonstrating with certainty which of these diets is most effective for patients with psoriasis, all participants reported a common benefit: weight loss”, Koo says. “Given that vegan, paleo and gluten-free diets aid with weight loss, it is worth experimenting with them.
What this means for your diet
The data extrapolated from the survey do not provide any definitive conclusions, Koo says. He does, however, believe that the results are significant. “Since the survey is based on real-life data – on that which works and doesn’t work for psoriasis sufferers – the results may be encouraging for patients,” he says. “They can try eliminating one of the foods on the list that activates the inflammatory response, or follow one of the dietary regimens reported in the survey as being the most effective, and monitor their own physical response over time.”
To do this, patients should keep a food diary and proceed by trial and error, “keeping an open mind, and remembering that what works for one person may not work for another,” explains Dr. Wilson Liao, the main author of the study. “They should also consider consulting a nutritionist, or a physician with nutritional expertise, to create a suitable dietary regimen based on their personal preferences and on their clinical history.”
According to Koo, it is reasonable to speculate that patients could also respond differently to various dietary strategies depending on the sub-type of psoriasis they are suffering from. Identifying the right combination of diet and disease sub-type is just one of the interesting challenges for future research.
Ideally, the data gathered through this survey could be used to develop rigorous clinical studies which are needed to properly clarify the relationship between diet and psoriasis.