A systematic review of 15 studies across five autoimmune diseases found Mediterranean diet adherence significantly improved quality of life in multiple sclerosis and celiac disease patients with moderate certainty of evidence. The analysis included patients with rheumatoid arthritis, Crohn's disease, ulcerative colitis, multiple sclerosis, and celiac disease, with one cohort study demonstrating reduced mortality in inflammatory bowel disease patients. This represents the most comprehensive evaluation to date of Mediterranean diet effects specifically in autoimmune populations, addressing a critical gap given that these conditions affect millions globally and often require lifelong immunosuppressive treatments. The quality of life improvements are particularly meaningful since autoimmune diseases frequently involve debilitating symptoms that standard medications don't fully address. While C-reactive protein reductions were inconsistent across studies, the mortality benefit in IBD patients suggests potential disease-modifying effects beyond symptom management. However, the evidence base remains limited with only five randomized trials, and the mechanisms linking Mediterranean diet components to autoimmune disease outcomes need clarification. The findings support Mediterranean diet as a safe, accessible adjunct therapy, though larger long-term studies are needed to establish definitive clinical recommendations.