The effects of oral iron supplementation on cognition in older children and adults: a systematic review and meta-analysis

Study answer

What this study found

Oral iron showed some evidence of benefit for cognition, but the effects were domain- and subgroup-specific. Attention and concentration improved in older children and women, and IQ improved in anaemic children and women, whereas memory, psychomotor function, and scholastic achievement were not improved in other groups. Overall, the findings suggest a modest positive effect of iron on selected cognitive outcomes, but not a broad cognitive benefit.

Study & population

Systematic review and meta-analysis of randomized controlled trials of oral iron supplementation in people aged 6 years and older.

Intervention

Oral iron supplementation was evaluated across randomized trials using tablets, capsules, pills, or capsules delivering about 17 to 260 mg/day, or 2 to 4 mg/kg/day, for 4 to 29 weeks.

Key limitation

The evidence base was limited by small sample sizes, short treatment durations, and generally weak study methods.

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Original abstract