A nutritional basis for lead pica

Lead pica is a puzzling behavioral phenomenon involving the continued voluntary ingestion of a toxic substance. Calcium deficiency produced an elevated proportion of lead ingestion while magnesium and zinc deficiency produced proportional levels of lead ingestion intermediate to control and calcium deficient rats. Partrial restoration of calcium did not eliminate the increased proportion of lead ingestion while full calcium restoration did. Calcium deficient rats offered lead to drink gained more weight than deficient rats not offered lead. Control animals showed a reduction in their intake of novel solutions ingested following intubation of lead acetate while calcium deficient animals did not. Rats deficient in calcium, iron and zinc also showed elevated proportional levels of quinine sulfate ingestion compared to controls suggesting that a pica may be a general response to nutritional deficiency. The increased proportion of lead ingestion by calcium, zinc and magnesium deficient rats and the failure of calcium deficient rats to form a learned aversion to lead acetate, suggests that mineral deficiency may be a major factor in producing lead pica.