Dietary inflammatory potential and severe headache or migraine: a systematic review of observational studies

OBJECTIVES: We conducted the current systematic review to investigate the association between dietary inflammatory index (DII) and severe headaches or migraine among adults via synthesizing observational evidence. METHOD: We conducted a systematic literature search of observational studies through PubMed, Scopus, and Web of Science databases from inception until July 2024. The PECO framework was implemented to select eligible studies as follows: Population (adults with severe headache or migraine), Exposure (individuals with the highest adherence to a pro-inflammatory diet), Comparison (individuals with the lowest adherence to a pro-inflammatory diet), Outcome (risk of developing severe headache or migraine, headaches frequency, duration, severity, and migraine-related disability). RESULTS: After reviewing six studies involving 31,958 individuals, we found that following an anti-inflammatory diet is associated with a lower frequency and severity of migraine headaches. Additionally, our research revealed that individuals with migraines tend to have lower adherence to an anti-inflammatory diet when compared to people without migraines. Surprisingly, adherence to a pro-inflammatory diet was linked to a reduced risk of chronic daily headaches. CONCLUSION: Present findings imply a negative link between an inflammatory diet and severe headaches or migraine. However, further well-designed longitudinal studies are needed to interpret the causality and shed light on the underlying mechanisms.