ABSTRACT
Objectives
Animal studies have suggested that dietary iron deficiency (ID) negatively affects dopamine (DA) synthesis and re-uptake, which in turn negatively affects memory and cognition. This study was intended to assess whether the pattern electroretinogram (pattern ERG) could be used as an indirect measure of DA in college-age women with and without ID by determining the extent to which features of the ERG were sensitive to iron status and were related to other indirect measures of DA.
Methods
The pattern ERG was measured in 21 iron deficient non-anemic (IDNA) and 21 iron sufficient (IS) women, who also performed a contrast detection and probabilistic selection task, both with concurrent electroencephalography (EEG). Both spontaneous and task-related blink rates were also measured.
Results
The implicit times of the A- and B-waves were significantly longer for the IDNA than for the IS women. Both the amplitudes and implicit times of the A- and B-waves were significantly correlated with levels of serum ferritin (sFt). Only the amplitude of the A-wave was correlated with spontaneous blink rate. It was possible to accurately identify a woman’s iron status solely on the basis of the implicit time of the B-wave. Finally, the implicit times of the ERG features mediated the relationship between iron levels and accuracy in the probabilistic selection task.
Conclusions
Results suggest the utility of the pattern ERG in testing the hypothesis that iron deficiency affects DA levels in humans and that this may be one of the mechanisms by which iron deficiency negatively affects cognition.
Acknowledgement
The data that support the findings of this study are available from the corresponding author [MJW], upon reasonable request. Thanks are due to Sarah Tang, Maddie Cupp, Hudia Jamshed, and Trinity Pruitt for their assistance in collecting the data. This study was not pre-registered.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Additional information
Funding
Notes on contributors
Sarah F. Newbolds
Sarah F. Newbolds is a doctoral student in the graduate program in Cellular and Behavioral Neurobiology and Department of Psychology at The University of Oklahoma.
Michael J. Wenger
Michael J. Wenger is a professor in Cellular and Behavioral Neurobiology and Department of Psychology at The University of Oklahoma.