Efficacy of the Mediterranean diet in the treatment of multiple sclerosis (RRMS): A systematic review and meta-analysis

BACKGROUND: Evidence supports a role for the Mediterranean Diet (MeD) in the treatment of Multiple Sclerosis (MS). This study aimed to evaluate the efficacy and safety of the MeD in patients with relapsing-remitting multiple sclerosis (RRMS) receiving with dimethyl fumarate (DMF) to provide a basis for clinical practice. METHODS: A comprehensive search was conducted to identify all relevant publications until September 1, 2025, across databases including PubMed, Web of Science, EMBASE, Cochrane Library, Medline via Web of Science, and Google Scholar. We included studies that evaluated the effect of the Mediterranean diet on multiple sclerosis, using relapse rate, expanded Disability Status Scale (EDSS), and multiple sclerosis quality of life-54 (MSQoL-54) as outcome measures. We followed PRISMA guidelines in the review process. We used descriptive statistics to summarise study characteristics, and applied a fixed-effects model and a random-effects model in the meta-analysis using RevMan 5.3 and Stata 18 software, while accounting for inter-study variability. We used the Cochrane RoB2 tool and the GRADE approach to assess the risk of bias and the overall quality of evidence. Egger's tests were conducted to assess publication bias. RESULTS: The meta-analysis included seven studies with a total of 1118 RRMS participants treated with DMF. The analysis demonstrated significant differences in relapse rate (OR=0.69; 95 %CI=(0.60,0.78);p<0.00001) and EDSS (MD=-0.53; 95 %CI=(-0.81,-0.25); p = 0.0002). However, in MSQoL-54, PHC (MD=15.51; 95 %CI=(-3.02,34.04); p = 0.10) and MHC (MD=3.81; 95 %CI=(-0.76,8.38); p = 0.10) no significant improvements were observed. CONCLUSIONS: The study outcomes suggest that the MeD in combination with DMF therapy, may be beneficial for RRMS patients who are undergoing DMF treatment, yielding beneficial effects. The findings highlight the effect of the MeD on the relapse rate and the intensity of disability symptoms in patients with multiple sclerosis. However, our study did not draw clear conclusions about the impact of MS patients' quality of life.