Participants and study design

We analyzed a randomly selected subset of 30 participants (aged 38.6 ± 2.3 years, 93% female, body mass index = 27.0 ± 1.1 kg/m²) from the original 141 study participants who completed participation in the Nutrition for Migraine Prevention trial. These participants were recruited from headache specialty clinics and community sources around the University of North Carolina. Eligible participants were required to be at least 18 years of age and met the 2004 International Classification of Headache Disorders criteria for migraine (5–20 migraine days per month). Exclusion criteria included regular use of dietary supplements containing fatty acids, food allergies resulting in a rash or dyspnea, aversion to eating seafood, pregnancy or a recent change in hormone use, marked depression, anxiety, or psychosis at the time of enrollment, active treatment for a major medical illness (e.g., autoimmune disorder, malignancy), recent substance abuse, or a history of head trauma, hemorrhage, hematoma, nervous system infections (e.g., meningitis, encephalitis), intracranial mass, clotting disorders, vasculitis, or cognitive dysfunction that would prevent informed consent. The study was registered at clinicaltrials.gov ({"type":"clinical-trial","attrs":{"text":"NCT02012790","term_id":"NCT02012790"}}NCT02012790) and was conducted from July 2014 to May 2018. Primary (plasma antinociceptive mediator 17-hydroxy-DHA and headache impact test) and secondary (headache frequency, patient-reported outcome measurement information system-29 profile, 17-hydroxy DHA trajectory) endpoints and sample size calculations are previously described (18).

All participants provided written informed consent. The study was approved by the Human Research Ethics Committee of the University of North Carolina (Institutional Review Board no.: 13-3284) and abided by the Declaration of Helsinki principles. In a three-armed, parallel-group, double-blinded, and randomized design, participants were randomly assigned to one of three dietary groups for a 16-week intervention: 1) a low n-3, high n-6 group (H6) consisting of the average US dietary intake of n-3 PUFAs and LNA (n = 10), 2) a high n-3, high n-6 group (H3H6) consisting of increased DHA and EPA intake with the average US dietary intake of LNA (n = 10), or 3) a high n-3, low n-6 group (H3) consisting of increased DHA and EPA with low LNA intake (n = 10). All participants had fasting blood withdrawn at baseline (week 0) and after 4, 10, and 16 weeks of diet exposure.