Iron supplementation findings varied by outcome and study design
Randomized trials reported improvements in fatigue, anxiety, and some cognitive measures, but not attention or depression. Benefits were not detected in analyses excluding participants with iron deficiency.
Based on the published abstract. The full paper may contain additional methods, results and limitations.
The 30-second takeaway
Iron supplementation was linked to improvements in selected symptoms and cognitive outcomes among people without anemia, but results differed across outcomes and analyses. Randomized trials did not show improvement in depression or attention. The lack of detected effects after excluding iron-deficient participants limits claims of benefit for people with adequate iron.
The abstract does not provide treatment durations, dosing details, confidence intervals, or adverse-event results. It also does not describe comparator arrangements within the pre-post studies, limiting interpretation of those analyses.
What researchers found
Fatigue in randomized trials
Iron supplementation versus placebo; assessment timing and the fatigue scale were not reported in the abstract.
Why study design matters
The randomized trials and before-and-after analyses gave different results for depression. Improvement appeared in the latter, while randomized comparisons did not show it. Measuring change over time answers a different question from comparing randomized groups.
The iron-status boundary
Subgroup analyses did not detect supplementation effects when participants with iron deficiency were excluded. This makes iron status central to interpreting the findings; absence of anemia did not mean that everyone had adequate iron.
The original publication
Psychiatric and cognitive outcomes of iron supplementation in non-anemic children, adolescents, and menstruating adults: A meta-analysis and systematic review.
Fiani D, Chahine S, Zaboube M et al.
Neurosci Biobehav Rev · 2025
- PubMed ID
- 40945632
- Record checked
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