In a study of more than 3,500 individuals with psoriasis, adopting a healthier diet was associated with an improvement in their symptoms – particularly a Mediterranean diet. 
In fact, the closer someone adhered to the Mediterranean diet, the less burdensome their psoriasis became, regardless of whether or not the individual was obese.
A Little About Psoriasis
Psoriasis is a non-contagious chronic skin condition that causes a thick, patchy, red rash with silvery, white scales. The most common type of the disease is known as plaque psoriasis. 
The telltale patches can show up anywhere on the body, but they most commonly appear on the scalp, elbows, knees, and lower back.
Psoriasis occurs most commonly in adults, though children can also be diagnosed with it.
Scientists aren’t sure what causes the skin condition, but it is believed to be caused by a problem with the immune system.
When someone has psoriasis, their immune system mistakenly attacks healthy skin cells as if it was fighting an infection. In people who don’t have the condition, the body makes new skin cells about every 4 weeks. However, psoriasis causes the body to create new skin cells every few days, resulting in the itchy and sometimes painful patches.
Psoriasis can be triggered by any number of things, but it is most commonly triggered by skin injury or infection; emotional stress; certain medications; smoking; and drinking alcohol.
The immune disorder affects some 6.7 million U.S. adults and is more likely to affect people with obesity and metabolic syndrome. 
Now the Mediterranean Diet
The Mediterranean diet is an eating pattern emphasizing fruits, vegetables, whole grains and legumes, fish, olive oil, and nuts. Red meat, dairy, and alcohol may be consumed in light moderation. It is considered one of the most “heart-healthy” diets you can adopt and comes highly recommended by health groups, such as the American Heart Association (AHA). 
Apart from heart health, the Mediterranean diet is associated with a long list of other health benefits. Based on the study’s findings, fighting immune-system disorders could possibly be added to that list.
Dr. Scott Flugman, a dermatologist at Northwell Health’s Huntington Hospital in Huntington, New York, said:
“If this finding is confirmed by further studies, it would lead to a significant change in the way dermatologists manage psoriasis, as it would mean that even a patient who is not overweight could improve their psoriasis through dietary modifications.”
For the study, researchers analyzed 35,735 participants’ answers to a web-based questionnaire. Of that number, 3,557 had psoriasis, and 878 of them described their symptoms as severe. 
The scientists assessed the participants’ dietary practices using a MEDI-LITE score ranging from 0 (no adherence) to 18 (maximum adherence).
The authors found a direct correlation between adherence to the Mediterranean diet and the severity of the participants’ psoriasis symptoms.
“Patients with severe psoriasis displayed low levels of adherence to the Mediterranean diet.”
Study leader Dr. Céline Phan, from the Hôpital Mondor in Créteil, France, remarked:
“This finding supports the hypothesis that the Mediterranean diet may slow the progression of psoriasis. If these findings are confirmed, adherence to a Mediterranean diet should be integrated into the routine management of moderate to severe psoriasis.”
Study Strengths and Limitations
Some of the strengths of the study include:
- The extensive nature of the questionnaire, which strengthens the results
- The dietary intake was assessed as highly accurate by using a minimum of 3 food surveys.
The study was limited by:
- The fact that all of the participants were volunteers, which makes it harder to generalize the results to a broader population. It’s important to point out that people who volunteer for medical studies tend to be more worried about their health than the general population.
- The study was observational and cannot prove causality.
The authors concluded:
“Further prospective observational studies and randomized clinical trials are needed to confirm these results, and experimental data are needed to establish the mechanistic links between psoriasis and diet.”
The findings are published in JAMA Dermatology.