Background Evidence suggests that iron deficiency (ID) affects cognitive performance, as measured in behavior. Although such effects must be mediated by changes in the brain, very few studies have included measures of brain activity to assess this relation. Objective We tested the hypothesis that provision of iron-biofortified beans would result in improvements in measures of iron status, brain dynamics, and behavior. Methods A double-blind, randomized, intervention study was conducted in 55 women aged 18–27 y with low iron status (serum ferritin