Abstract
Of all the nutritional challenges in the world, iron deficiency (ID) is the most prevalent, and can be found at high rates in both developing and developed countries. The negative impacts of ID include changes such as increases in contrast detection thresholds and decreases in attentional control and memory retrieval efficiency, and (in college-aged women) decrements in academic standing. Animal models of ID have consistently indicated effects of ID on dopamine (DA) synthesis and regulation and energy expenditure. The work presented here tests the extent to which the effects of ID in humans can be better quantified by focusing on behavioral measures that have been shown to be directly related to levels of DA, and on measures of energy expenditure. A set of iron sufficient and iron deficient non-anemic women learned two visual categorization tasks while concurrent EEG was acquired. These tasks have been shown to be reliant on declarative and procedural memory systems (Ashby & Crossley, 2010), and to be sensitive to dopaminergic status. Behavioral performance was assessed as inverse efficiency (mean RT / P(C); Townsend & Ashby, 1978), dopaminergic status was assessed by task-related blink rate (Jongkees & Colzato, 2016), and energy expenditure was assessed using a neural efficiency score constructed as the ratio of the cumulative hazard function for the RT distribution and the cumulative global field power of the EEG, which we have shown to be related to metabolic measures of energy expenditure. Results showed that lower iron status was related to higher inverse efficiency, lower neural efficiency, and lower task-related blink rates. All of this suggests that the impact of ID can be better quantified by focusing on measures of DA status and energy expenditure.
Acknowledgement: University of Oklahoma, Vice President for Research