Chromium and zinc concentrations in pediatric patients receiving long-term parenteral nutrition

Serum, urine, and parenteral nutrition (PN) chromium and zinc concentrations in pediatric patients receiving long-term PN were studied. Serum, urine, and PN chromium and zinc concentrations were measured at baseline and four to six months later in four infants (less than 1 year old) and seven children (1-12 years old) receiving long-term PN. In the children, serum, urine, and PN solution zinc concentrations were measured monthly after the amino acid product was changed from a standard to a pediatric product with monthly dosages of 0, 20, 30, and 40 mg of cysteine hydrochloride per gram of amino acids. The mean +/- S.D. baseline serum chromium concentration was 4.9 +/- 1.9 mu g/L (normal value, <0.3 mu g/L); the urine chromium concentration ranged from 3.4 to 32.2 mu g/L. The mean +/- S.D. prescribed chromium dosage was 0.18 +/- 0.05 mu g/kg/day, and the dosage delivered in PN solutions was 0.41 +/- 0.23 mu g/ kg/day. At baseline, the mean +/- S.D, serum zinc concentration was 1383 +/- 472 mu g/L (normal range, 430 to 940 mu g/ L), and the prescribed and delivered zinc dosages were 177 +/- 10 and 238 +/- 145 mu g/kg/ day, respectively. With 20, 30, and 40 mg of cysteine per gram of amino acids, the mean +/- S.D. serum zinc concentration was 1728 +/- 782, 1664 +/- 349, and 1685 +/- 268 mu g/L, respectively, and the actual zinc dosages delivered were 209 +/- 10, 270 +/- 148, and 322 +/- 194 mu g/kg/day, respectively. Serum and urine chromium concentrations were abnormally high in infants and children receiving PN solutions supplemented with normal doses of these trace elements; an escalating dosage of cysteine in the children tended to increase serum and urine zinc concentrations.