Iron deficiency negatively affects behavioral measures of learning, indirect neural measures of dopamine, and neural efficiency

Iron deficiency (ID) is the most prevalent nutrient deficiency in the world,with a growing literature documenting the negative effects of ID on per-ception, attention, and memory. Animal models of ID suggest that dys-regulation of dopamine is responsible for the deficits in memory. However,evidence that ID affects dopamine in humans is extremely limited. We re-port the results of a study involving college-aged women with and without IDlearning two different category structures—a rule-based and an information-integration structure—selected based on the putative differential role ofdopamine in learning these two structures. ID non-anemic (IDNA) andiron sufficient (IS) women completed 1200 learning trials for each structure.EEG was collected to assess effects of ID on features affected by dopaminergicstate: error related negativity (ERN) and positivity (Pe), feedback-relatednegativity (FRN), and task-related blink rate. In addition, we examined theEEG data for dynamics distinguishing IDNA from IS women, including ameasure of neural efficiency. Both groups of women were able to learn bothstructures. However, IDNA women were initially slower and less accuratethan IS women, specifically for the rule-based structure. There were largeand persistent group differences on the measures of brain dynamics and neu-ral efficiency. Results are discussed with respect to the selective impact ofID on initial rule-based learning and the persistent effect of ID on dopaminesignaling and energetic efficiency