RESUMO
BACKGROUND: Literature suggests a relationship between estrogen levels and migraine headache pathogenesis. However, the effect of soy isoflavones on migraine characteristic remains unclear. This study aimed to investigate the effect of soy isoflavones on migraine characteristics and calcitonin gene-related peptide (CGRP) levels in women with migraine. METHODS: Eighty-three participants completed a randomized double-blind controlled trial, receiving 50 mg per day soy isoflavones or placebo supplementation for 8 weeks. Migraine severity, migraine days per month, frequency and duration of attacks, mental status, quality of life and serum CGRP levels were measured at baseline and the end of the intervention. Bivariate comparison and intention-to-treat (ITT) were used for analysis. RESULTS: Soy isoflavones intake resulted in a significant decrease in mean frequency (-2.36 vs -0.43, P < 0.001), duration (-2.50 vs -0.02, P < 0.001) of migraine attacks and CGRP level (-12.18 ng/l vs -8.62, P = 0.002) in compared to placebo group. Also, a significant improvement was found in quality of life (16.76 vs 2.52, P < 0.001). Although, reduction in the migraine severity and mental status did not reach a statistically significant level (P > 0.05). CONCLUSION: soy isoflavones supplementation may be considered as a complementary treatment for women with migraine to improve migraine characteristics and reduce the burden of disease.