Zinc in attention-deficit/hyperactivity disorder.
OBJECTIVE
The aim of this study was to review the published evidence for a role of zinc nutrition in attention-deficit/hyperactivity disorder (ADHD).


METHODS
A computer literature search was supplemented by the authors' knowledge.


RESULTS
Numerous controlled studies report cross-sectional evidence of lower zinc tissue levels (serum, red cells, hair, urine, nails) in children who have ADHD, compared to normal controls and population norms. A few studies show correlations of zinc level with either clinical severity or a change thereof in response to stimulant or chemical challenge. Two placebo-controlled trials--one of zinc monotherapy, the other of zinc supplementation of methylphenidate--reported significant benefit. However, diagnostic procedures and sample representativeness were often not clear, and most such reports have come from countries and cultures with different diets and/or socioeconomic realities than are found in the United States (only one American sample in nine published reports). In particular, both positive clinical trials of zinc supplementation came from the Mid-East (Turkey and Iran), an area with suspected endemic zinc deficiency. The largest of these trials used zinc doses above the recommended upper tolerable limit and had a 2 in 3 dropout rate.


CONCLUSIONS
It is not clear how well the accumulating evidence for a possible role of zinc in ADHD applies to middle-class American children. However, the evidence appears strong enough to warrant further controlled study in well-diagnosed samples representative of the socioeconomic spectrum. Hypothesis-testing clinical trials are needed of this potential treatment that, if found effective, might become a relatively safe, cheap substitute for, or adjunct to, current treatments in some patients. At present, it should remain an investigational treatment.
Arnold
L Eugene
LE
Department of Psychiatry, Ohio State University, Columbus, OH 43074, USA. arnold6@osu.edu
DiSilvestro
Robert A
RA
D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy / Q000378:metabolism* / Q000523:psychology; D001921:Brain / Q000502:physiology; D002648:Child; D002986:Clinical Trials as Topic; D006801:Humans; D015032:Zinc / Q000172:deficiency / Q000378:metabolism / Q000502:physiology* / Q000627:therapeutic use
D015032:Zinc