Iron treatment normalizes cognitive functioning in young women.
Journal
  The American journal of clinical nutrition.
Citation
  Am J Clin Nutr. 85(3):778-87
Publication date
  2007 Mar
Authors
  Murray-Kolb LE
Beard JL
Investigators
  John Beard
Grant agencies
  National Center for Research Resources
Grants
  NCRR MO1RR10732
MeSH headings
  Cognition
Iron
MeSH qualifiers
  physiology
pharmacology
Abstract
  BACKGROUND: Evidence suggests that brain iron deficiency at any time in life may disrupt metabolic processes and subsequently change cognitive and behavioral functioning. Women of reproductive age are among those most vulnerable to iron deficiency and may be at high risk for cognitive alterations due to iron deficiency. OBJECTIVE: We aimed to examine the relation between iron status and cognitive abilities in young women. DESIGN: A blinded, placebo-controlled, stratified intervention study was conducted in women aged 18-35 y of varied iron status who were randomly assigned to receive iron supplements or a placebo. Cognition was assessed by using 8 cognitive performance tasks (from Detterman's Cognitive Abilities Test) at baseline (n = 149) and after 16 wk of treatment (n = 113). RESULTS: At baseline, the iron-sufficient women (n = 42) performed better on cognitive tasks (P = 0.011) and completed them faster (P = 0.038) than did the women with iron deficiency anemia (n = 34). Factors representing performance accuracy and the time needed to complete the tasks by the iron-deficient but nonanemic women (n = 73) were intermediate between the 2 extremes of iron status. After treatment, a significant improvement in serum ferritin was associated with a 5-7-fold improvement in cognitive performance, whereas a significant improvement in hemoglobin was related to improved speed in completing the cognitive tasks. CONCLUSIONS: Iron status is a significant factor in cognitive performance in women of reproductive age. Severity of anemia primarily affects processing speed, and severity of iron deficiency affects accuracy of cognitive function over a broad range of tasks. Thus, the effects of iron deficiency on cognition are not limited to the developing brain.