Effects of Meat Consumption on Multiple Sclerosis: A Systematic Review and Meta-analysis

Backgrounds and Objectives: Multiple sclerosis is a common cause of neurological disabilities worldwide. Diet is a potential risk factor for the pathogenesis of multiple sclerosis  and dietary intervention can be used as a prevention method for multiple sclerosis. The purpose of this study was the investigation of relationships between the type of meat consumed by the patients and multiple sclerosis. Materials and Methods: In this systematic review and meta-analysis, Persian and English databases were searched, including PubMed, MEDLINE, Web of Science, Scopus, Google Scholar, Springer, Cochrane library, Magiran and Gray Literature (Bibliograph, Congress abstracts), for the publications of 1998–2020, using keywords of meat, fish meat, red meat, multiple sclerosis, processed and non-processed meat. Out of 186 selected articles, 30 full-text articles were entered into the quality assessment process and results of 10 articles were analyzed in this study. Results: The sample size of ten selected studies was 11024. Statistically significant decreasing effects were identified for white meat on multiple sclerosis disease with the odds ratio of 0.81 [95% confidence interval (0.74, 0.88)] and significant correlations were detected between non-processed meat and multiple sclerosis with the odds ratio of 0.85 [95% confidence interval (0.75, 0.95)]. Calculated odds ratio between the processed meat and multiple sclerosis was 1.21 [95% confidence interval (0.93, 1.49)].  Conclusion: Processed red meat consumption increases risks of multiple sclerosis. Diets of non-processed red meats as well as white meats include protective effects on this disease.