The Effect of Dietary Interventions on Psoriasis Severity in Overweight and Obese Adults: a systematic review and meta-analysis

Psoriasis is a common autoimmune skin disorder associated with comorbidities such as obesity, metabolic syndrome, and cardiovascular complications. Dietary modifications and increased physical activity leading to weight loss are promising strategies to enhance the effectiveness of standard medical therapy of psoriasis. The aim of this study is to review and synthetize evidence from randomized controlled trials (RCTs) investigating the effects of dietary interventions on psoriasis outcomes, primarily the Psoriasis Area and Severity Index (PASI). The study consisted of a systematic literature review and a meta-analysis. Eligible studies included overweight or obese adults with psoriasis who continued stable anti-psoriatic treatment while undergoing dietary interventions with or without physical activity. A total of 13 studies were included in the review, comprising 12 RCTs and one single-arm study. The interventions comprised various dietary approaches, including low-calorie diet (LCD), the Ketogenic diet, very-low-calorie ketogenic diet (VLCKD), intermittent fasting, the Mediterranean diet, and other dietary interventions, applied either alone or in combination with physical activity. To reduce heterogeneity, only five studies evaluating low-calorie diets were included in the meta-analysis. The pooled analysis demonstrated a statistically significant benefit of LCD intervention on psoriasis severity: MD = −0.69 (95%CI: −1.05 to −0.33), indicating a greater reduction in PASI scores among participants receiving dietary intervention compared with controls receiving standard medical treatment alone. Overall, the findings suggest that dietary management aimed at weight reduction in overweight and obese individuals with psoriasis may serve as an effective adjunct to standard medical therapy, contributing to improved disease severity.