molecules Review Magnesium, Iron, Zinc, Copper and Selenium Status in Attention-Deficit/Hyperactivity Disorder (ADHD) Harry Robberecht *, Annelies A. J. Verlaet, Annelies Breynaert, Tess De Bruyne and Nina Hermans Laboratory of Nutrition and Functional Food Science, NatuRA (Natural Products and Food Research and Analysis), Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium;
[email protected] (A.A.J.V.);
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[email protected] (N.H.) * Correspondence:
[email protected]; Tel.: +00-32-3265-2706 Academic Editors: Alejandro Samhan-Arias and Valeria M. Nurchi Received: 8 July 2020; Accepted: 25 September 2020; Published: 27 September 2020 Abstract: In this study, we critically review the literature concerning the relation of Mg, Fe, Zn, Cu and Se and attention-deficit/hyperactivity disorder (ADHD). Elemental status is estimated using peripheral blood parameters, hair, urine, daily intake and response to supplementation. The observed associations between concentration levels of the elements Mg, Fe, Zn, Cu and Se and ADHD symptoms are contradictory. This is partly due to the heterogeneity and complexity of the disorder. As a trend, lower ferritin and zinc levels can be observed. However, this correlation is not causative, as illustrated by placebo-controlled trials reporting conflicting evidence on the efficacy of supplementation. Well-defined studies on changes in concentration levels of the elements in relation to ADHD symptoms before and after treatment with therapeutics it will be possible to shed more light on the significance of these elements in this behavioral disorder. The discussion on whether a change in concentration of an element is cause or consequence of ADHD is not within the scope of this article.