Molybdenum—Closing the gap

The essential trace element molybdenum (Mo) is increasingly considered in pediatric studies, as recently by Du et al.,1 other sectors contributing to the knowledge on Mo in infancy and childhood.2-4 Almost all reported small numbers of high urinary Mo values and/or elevated plasma concentrations, both warranting critical scrutiny. However, potentially relevant background data remained fragmented, especially the analytical assessment of Mo in dietary intake. Earlier, detailed prospective (metabolic) investigations with stable isotopes in adults and infants showed a high Mo absorption as reflected in high urinary excretion.5, 6 Increased plasma levels were described at high nutritional intakes7 but also in the context of kidney disease.8 These observations call for a differentiation of potential sources of excessive Mo intakes, for example, by infant formulae, diets for medical purposes, medication, supplementation or in environmental contexts, to identify starting points for their prevention. For future trace element studies in childhood including Mo it can be deduced, that multidimensional aspects should be considered early on in the study planning stage, for example, to preserve samples of food and other intakes from the study participants before urine or plasma collection, for example, 72 h, and to assess the renal function. This would render possible to explain high Mo levels post hoc and efficiently detect potential risks in food or other intakes as general screening of Mo intake would be extremely complex and presumably ineffective. Upcoming studies could seize the opportunity to contribute to closing this existing gap of knowledge about Mo metabolism. The author declares no conflicts of interest.