Effects of serum zinc supplementation on pica behavior of persons with mental retardation.

Although pica is one of the most frequently observed eating dysfunctions among people with mental retardation, it is significantly underreported in the literature. Of 806 institutionalized adults with mental retardation in the present study, 15.5% exhibited pica. Prevalence estimates from previous studies have ranged from 25.8% to 3%. Fifty-four percent of the pica group had serum zinc levels below normal range, whereas 7% of the control group had serum zinc levels below the normal range. After supplementation with chelated zinc, residents had significant reductions in pica. Data indicated zinc as a possible adjunct to other treatment approaches.