How does iron impact the workings of our brain and, especially, our cognitive abilities, including concentration and memory?
According to a recent study in the Journal of Neuroscience, higher iron concentration in a key brain region called the putamen was linked to better cognitive abilities in youth and young adults.
By using MRI brain imaging to measure iron levels, the researchers discovered that individuals who accumulated more iron in the putamen from their late teens into their early 20s tended to perform better on tests of complex cognition, including tasks requiring planning, problem-solving, attentional control and working memory.
Lower putamen iron levels, on the other hand, were associated with relatively poorer performance in these higher-order cognitive domains.
While more research is still needed, these findings highlight the importance of getting adequate iron during the transition to adulthood when key brain regions are still developing.
What are the Effects of Oral iron Supplementation on Cognition?
According to this systematic review and meta-analysis, oral iron supplementation appears to have some beneficial effects on cognition in older children and adults, but the findings are limited and require further research.
Here are the key points:
- Iron supplementation improved attention and concentration in adolescents and women, regardless of their baseline iron status. This effect was seen across several studies and was considered a moderate effect size.
- In children and women who were anemic (low hemoglobin levels) at baseline, iron supplementation improved their intelligence quotient (IQ) scores by about 2.5 points on average compared to placebo groups. However, iron did not improve IQ in those who were not anemic at baseline.
- The review did not find evidence that iron supplementation improved memory, psychomotor skills (coordination), or scholastic achievement (school performance).
- Most of the included studies were small, had some methodological limitations, and were of relatively short duration (4 weeks to 7 months). Larger, longer, and higher-quality studies are needed to confirm these findings.
- No studies looked at the effects of iron in men, post-menopausal women, or the elderly, so the effects in these groups remain unknown.
In summary, while this analysis suggests some cognition benefits from iron for those deficient, especially for attention, concentration and IQ in anemic groups, the evidence is still quite limited.
More rigorous, long-term research is required to make stronger conclusions about the role of iron supplementation for cognitive function, especially in different population group.
Can Low Iron Cause Concentration Problems?
It's important to say that while evidence for iron supplementation to enhance memory and cognition is limited, there is substantial evidence that low iron significantly impacts the brain. Numerous studies such as this have found links between iron deficiency and impairments in cognition, attention, intelligence, sensory perception, emotions, behavior, and motor skills.
The brain effects of low iron seem to start early. In infants and young children, iron deficiency anemia has been associated with poorer cognitive and motor development, as well as behavioral issues like reduced responsiveness, irritability and inhibition. Some of these effects appear to persist long-term, with formerly anemic children showing poorer cognitive scores and more timidity even years later.
But it's not just full-blown anemia - even iron deficiency without anemia can cause cognitive disturbances. Studies in adolescents and adults with iron deficiency have found impairments in areas like verbal learning, memory, discrimination and selective attention compared to those with normal iron levels.
So what's going on?
Iron plays a key role in brain development and function. It is involved in myelination of neurons, mitochondrial function, neurotransmitter production and more. Iron deficiency can alter dopamine metabolism and neurotransmitter systems critical for cognition, behavior and reward. It may damage the hippocampus and prefrontal cortex and impair connectivity in pathways related to motor skills and emotional processing.
The good news is that many of these effects appear to be at least partially reversible with iron treatment, especially when supplements are started early.
However, prompt diagnosis and effective iron repletion seem key, as cognitive deficits can persist even after iron levels are restored if the deficiency occurred during a sensitive window of brain development.
Sources
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Ferreira, A.; Neves, P.; Gozzelino, R. Multilevel Impacts of Iron in the Brain: The Cross Talk between Neurophysiological Mechanisms, Cognition, and Social Behavior. Pharmaceuticals 2019, 12, 126. https://doi.org/10.3390/ph12030126
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Larsen, B.; Bourque, J.; Moore, T.M.; Adebimpe, A.; Calkins, M.E.; Elliott, M.A.; Gur, R.C.; Gur, R.E.; Moberg, P.J.; Roalf, D.R.; Ruparel, K.; Turetsky, B.I.; Vandekar, S.N.; Wolf, D.H.; Shinohara, R.T.; Satterthwaite, T.D. Longitudinal Development of Brain Iron Is Linked to Cognition in Youth. Journal of Neuroscience 26 February 2020, 40 (9) 1810-1818; DOI: 10.1523/JNEUROSCI.2434-19.2020
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Falkingham, M.; Abdelhamid, A.; Curtis, P. et al. The effects of oral iron supplementation on cognition in older children and adults: a systematic review and meta-analysis. Nutr J 9, 4 (2010). https://doi.org/10.1186/1475-2891-9-4
