Impact of the Mediterranean Diet on Patients with Psoriasis (MEDIPSO): protocol for a randomized clinical trial. (Preprint)

BACKGROUND Psoriasis is an inflammatory disease whose treatment currently focuses on molecular targets. However, evidence suggests that dietary interventions may also be useful for controlling inflammation in this condition. The Mediterranean diet, typical of southern European countries, has been shown to decrease cardiovascular mortality. These cardiovascular benefits may be due in large part to its anti-inflammatory potential, which makes studying its role in immune-mediated diseases of interest. In fact, several observational studies have addressed this issue, showing potential benefits on Psoriasis Area and Severity Index (PASI) reduction in psoriasis. Nevertheless, clinical trials that overcome the methodological problems of these designs and allow the establishment of specific recommendations for this diet in psoriasis are lacking. OBJECTIVE The MEDIPSO study aims to evaluate the impact of a high intensity dietary intervention with Mediterranean diet on patients with psoriasis. The effect of the intervention on skin involvement, metabolic parameters and inflammatory cytokines will be assessed. The emotional and quality of life impact will also be evaluated with validated questionnaires. In addition, a methodological analysis will be carried out in order to improve the design for a larger scale clinical trial in the future. METHODS A randomized controlled, open-label, single-blinded (evaluator) clinical trial was designed. Throughout the study, 38 patients with mild-to-moderate psoriasis will be randomized into two arms: intervention group (high-intensity Mediterranean diet intervention) or control group (standard of care). Patients assigned to the experimental group will undergo dietary education for the adoption of the Mediterranean diet for four months, with monthly monitoring by experienced nutritionists. Patients will be given 500 ml of extra virgin olive oil per week and informative material about the Mediterranean diet, as well as recipes and weekly menus. Patients assigned to the control group will be provided with standard recommendations for a low-fat diet with no monitoring by nutritionists. All patients will undergo a baseline visit, a two-month follow up visit and a final visit after four months. Blood tests will be performed at the beginning and at the end of the study. This study protocol was approved by the Institutional Review Board of the Hospital Ramón y Cajal (Madrid) in July 2023. RESULTS Enrollment is estimated to conclude by October 2024 and data collection will finish by February 2025. Findings will be presented at national and international congresses, and peer-reviewed journals. CONCLUSIONS This protocol presents the design of a clinical trial in which the intervention consists of implementing the Mediterranean diet in patients with psoriasis, in order to evaluate the benefit of this dietary pattern in terms of skin involvement, systemic inflammation, and quality of life. CLINICALTRIAL clinicaltrials.gov identifier: NCT06257641.