Molybdenum requirements in low-birth-weight infants receiving parenteral and enteral nutrition

Background: Molybdenum (Mo) is an essential trace element required by three enzymatic systems, yet there are no reports of Mo deficiency in infants. L ow-birth-weight infants (LBW) might be at risk for Mo deficiency because th ey are born before adequate stores for Mo can be acquired, they have rapid growth requiring increased intakes, and they frequently receive supplementa l parenteral nutrition (SPN) and total parenteral nutrition (TPN) unsupplem ented with molybdenum. Methods: To investigate Mo requirements of LBW infan ts (n = 16; birth weight, 1336 +/- 351 g; gestational age, 29.8 +/- 2.5 wee ks; M +/- SD), the authors collected all feeds, urine, and feces prior to T PN (baseline, n = 16, collections = 16), during TPN (n = 9, collections = 1 9), during SPN (n = 13, collections = 17), and after one week of full oral feeds (FOFs) of formula or human milli. (FOF, n = 16, collections = 16). Re sults: Infant weights at collection times were: 1.3 +/- 0.3 g, 1.27 +/- 0.4 g, 1.4 +/- 0.3 g, and 1.7 +/- 0.5 g, respectively. Mo intake was 0.03 +/- 0.1 mu g/d, 0.34 +/- 0.1 mu g/d, 1.25 +/- 1.7 mu g/d, and 6.1 +/- 2.5 mu g/ d. Mo output was 0.64 +/- 0.6, 0.34 +/-. 0.5, 0-68 +/- 0.8, and 4.1 +/- 2.5 mu g/d. Mo balance at these times; was -0.60 +/- 0.5, -0.001 +/- 0.5, 0.57 +/- 1.9, and 2.0 +/- 2.9 mu g/d. Mo balance increased with time, jet some infants were always in negative balance, even though Mo intakes exceeded re commendations. Conclusions: The authors speculate that an intravenous intak e of 1 mu g/kg/d (10 nmol/kg/d) and an oral intake of 4-6 mu g/kg/d (40-60 nmol/kg/d) would be adequate for the LBW infant.