A 16-week Mediterranean diet intervention reduced psoriasis severity by 32% compared to standard low-fat dietary advice in a randomized trial of 158 adults with mild-to-moderate disease. Participants following the Mediterranean protocol with dietitian guidance and weekly olive oil provision showed significant improvements on the Psoriasis Area and Severity Index, alongside enhanced metabolic markers and reduced inflammatory biomarkers. This represents the first rigorous randomized evidence linking dietary intervention directly to psoriasis improvement, validating decades of observational research suggesting anti-inflammatory eating patterns benefit autoimmune skin conditions. The Mediterranean diet's documented effects on reducing systemic inflammation and improving gut microbiome diversity likely explain the mechanism, as psoriasis involves both immune dysregulation and chronic inflammatory pathways. The 32% improvement approaches the threshold considered clinically meaningful in dermatology, suggesting dietary modification could serve as adjunctive therapy alongside topical treatments. However, the single-center design and 16-week duration limit broader applicability. The findings support integrating nutritional counseling into psoriasis management, particularly for patients seeking non-pharmacological approaches or those with comorbid metabolic conditions where Mediterranean eating patterns offer dual benefits.