Written by Chrystal Moulton, Science Writer. Serum zinc levels were significantly lower in children with ADHD compared to controls (P<0.05).

ADHD is a developmental disorder affecting 7.6% of children between 3-12 years old.(1) ADHD is characterized by hyperactivity, impulsivity, and inattention, which research shows is a result of alterations in gene expression in the brain.(2) Because this disorder affects an individuals ability to focus or control impulses, children with the disorder may experience negative interactions in relationships at home, school, and in their communities.(3) Thus, treatment is necessary to ensure positive and constructive learning and relationship development during adolescence. Additional research points to deficits in trace minerals as a possible reason for ADHD development, with the hope that supplementation with trace minerals would ameliorate symptoms of ADHD. (4-6) However, studies thus far have been contradictory as some show correlation between trace mineral deficiency and ADHD and others show elevated trace mineral levels.(7-10) In the current study, researchers conducted a meta-analysis of studies investigating the association between serum trace mineral levels in children diagnosed with ADHD.(11)

Studies were selected for this meta-analysis if they met these criteria:

1. Language was either English or Chinese (researchers in this study were Chinese)
2. Study design is case-control trial
3. Participants were children (3-18 years old)
4. Levels of copper, iron, and zinc were measured
5. Researchers compared participants with ADHD against controls without ADHD
6. Means and standard deviations of metal concentrations in both cases and controls

Researchers utilized the Newcastle-Ottawa Scale to assess the quality of studies which were included in the meta-analysis. Sensitivity analysis was also conducted to determine whether any study or studies influenced outcomes and publication bias was assessed using Egger’s test and funnel-plot symmetry.

Ultimately, 46 studies were included in this meta-analysis with most studies from Asia (n= 28) and Europe (n= 10). The remaining studies were based in Africa, the Americas, and Oceania (n= 8). Many of the studies were published between 2010 and 2025 (n= 30). Results are as follows:

• Serum zinc levels were significantly lower in children with ADHD compared to controls (P<0.05). Researchers also observed a more significant decrease in serum levels in ADHD cases in developing regions (P<0.05).
• Serum iron levels were significantly lower in children with ADHD compared to controls (P<0.001). However, assessing the economic level of participants based on country, researchers found that low serum iron levels were only statistically significant in studies done in developing countries (P<0.05). No statistically significant effect for serum iron and ADHD was found in developed countries.
• Serum copper levels were lower in adolescents with ADHD. However, the difference didn’t reach statistical significance. Serum copper levels, however, were statistically lower in adolescents with ADHD in developing countries versus developed countries (P<0.05).

Furthermore, sensitivity analysis revealed no evidence of publication bias. There was high heterogeneity across all studies in this analysis. Trim-fill analysis was done to assess the robustness of the findings. Trim-fill analysis maintained the significant inverse relationship between serum iron and zinc and the presence of ADHD. Also, the association between low serum copper levels and ADHD became statistically significant following trim-fill analysis.

Overall, this meta-analysis revealed that serum zinc, iron and ferritin levels are significantly lower in children with ADHD compared to health controls. No statistically significant effect was observed in serum copper levels in children with ADHD compared to controls. Additional studies will be needed to verify these findings.

Source: Wang, Wei, Lei Tian, Huiqiong Xu, Jixing Zhou, and Menglong Geng. “Essential Trace Elements Zinc, Iron, Copper and Attention-Deficit/Hyperactivity Disorder in Children and Adolescents: A Systematic Review and Meta-Analysis of Case–Control Studies.” Nutrients 18, no. 11 (2026): 1797.

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Posted August 5, 2026.

Chrystal is a 2008 graduate of the University of Illinois at Chicago. She graduated with a bachelor’s in psychology with a focus on premedical studies and is a licensed project manager. She currently resides in Chicago.

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