Abstract
Migraine is a primary headache disorder affecting about 14% of the global population. The knowledge about migraine pathophysiology is increasing constantly; however, there are still many unknowns and uncertainties. Intestinal microbiota builds the gut environment together with metabolites and the immune system. Its connections with disorders outside the digestive system have been described, mainly neuropsychiatric diseases, due to the existence of the microbiota-gut-brain axis. Therefore, it is suggested that migraine is also correlated with changes in the microbiome. The review aimed to summarize the available literature related to the topic. We performed an electronic article search through the Embase Database and PubMed Database, and included 14 articles after analysis under the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) 2020 guidelines. Subsequently, a meta-analysis of randomized controlled clinical trials summarizing probiotics' effect on migraine prevention was conducted based on the same guidelines and resulted in including 2 adequate trials. Microbiome alterations have been observed in migraine patients with an influence on clinical presentation. Preclinical studies suggested a direct connection between migraine and microbiome changes. The meta-analysis has shown the influence of probiotics on migraine frequency (p = 0.003; Hedges' g = 1.22; standard error (SE) = 0.41), and no impact on migraine severity (p = 0.069; Hedges' g = 1.10; SE = 0.61) and attacks' duration (p = 0.149; Hedges' g = 0.18; SE = 0.15). However, the former was close to the statistical significance. The following work demonstrates a correlation between migraine and microbiome, which has a putative positive impact on migraine management. Moreover, probiotic supplementation can alleviate migraine symptoms. However, the main limitation is the limited number of studies, together with high heterogeneity and limited methodological consistency in the meta-analysis.