Association of diet quality, dietary acid load and antioxidant index with migraine severity, disability, and duration: a cross-sectional study

BACKGROUND: Migraine disproportionately affects women and may be modulated by dietary factors. This cross-sectional study investigated associations between diet quality (Alternative Healthy Eating Index, AHEI), dietary acid load (Net Endogenous Acid Production, NEAP), and dietary antioxidant capacity (Dietary Antioxidant Index, DAI) with migraine pain intensity, disability, and headache duration in Iranian women. METHODS: A total of 280 women aged 18–50 years with migraine (diagnosed per ICHD-3 criteria) were recruited from neurology clinics in Zanjan, Iran (August 2024–June 2025). Dietary intake was assessed using a validated 168-item food frequency questionnaire. AHEI, NEAP, and DAI scores were calculated and stratified into tertiles. Outcomes included pain intensity (Visual Analog Scale [VAS]: mild [1–3; reference], moderate [4–7], severe [8–10]), disability (Migraine Disability Assessment Scale [MIDAS]: none [0–5; reference], mild [6–10], moderate [11–20], severe [> 20]), and mean headache duration (hours). Multivariable-adjusted multinomial logistic regression (for VAS and MIDAS) and linear regression (for duration) were used to estimate odds ratios (ORs) and β coefficients with 95% confidence intervals (CIs), comparing the middle (T2) and highest (T3) tertiles versus the lowest (T1; reference), adjusted for age, BMI, physical activity, prophylactic medication use, and socioeconomic status. P-for-trend was calculated using tertile medians as continuous variables. RESULTS: Higher AHEI tertiles showed graded protective associations with severe pain (T3 OR 0.69, 95% CI 0.51–0.89, p = 0.010; P-for-trend = 0.009) and shorter headache duration (T3 β − 1.58, 95% CI − 2.75 to − 0.41, p = 0.009; P-for-trend = 0.008). Higher NEAP tertiles were linked to increased severe pain (T3 OR 1.38, 95% CI 1.08–1.66, p = 0.021; P-for-trend = 0.018), severe disability (T3 OR 1.29, 95% CI 1.02–1.56, p = 0.044; P-for-trend = 0.039), and longer duration (T3 β 1.28, 95% CI 0.25–2.31, p = 0.015; P-for-trend = 0.013). Higher DAI tertiles demonstrated the strongest graded reductions in moderate pain (T3 OR 0.59, 95% CI 0.41–0.83, p = 0.035; P-for-trend = 0.012), severe pain (T3 OR 0.47, 95% CI 0.33–0.74, p = 0.024; P-for-trend = 0.007), moderate disability (T3 OR 0.73, 95% CI 0.52–0.97, p = 0.048; P-for-trend = 0.031), severe disability (T3 OR 0.69, 95% CI 0.47–0.91, p = 0.038; P-for-trend = 0.022), and shorter duration (T3 β − 1.34, 95% CI − 2.33 to − 0.35, p = 0.008; P-for-trend = 0.006). CONCLUSIONS: Better diet quality and higher antioxidant capacity were associated with reduced migraine burden, while higher dietary acid load correlated with increased burden. These findings highlight potential graded associations and support the need for prospective studies to establish causality and evaluate dietary interventions in women with migraine.