Biokinetic studies in humans with stable isotopes as tracers. Part 2: Uptake of molybdenum from aqueous solutions and labelled foodstuffs

Molybdenum (Mo) has been identified as an essential trace metal for humans. The present study was aimed at the assessment of data on intestinal Mo abs orption from aqueous solutions and from foodstuffs in humans applying the m ethodology for instrinsic labelling described in Part 1. The intestinal abs orption of Mo was investigated by means of a double tracer method in 3 heal thy volunteers on a total of 15 occasions. When administered as aqueous sol ution, almost complete uptake of Mo was observed up to doses of 1 mg and on ly a slight decrease for higher doses. But addition of black tea reduces th e absorbed fraction by about a factor of ten. Studying Mo absorption from f ood, intrinsically labelled cress showed a reduced uptake as compared to ex trinsically labelled cress and aqueous solutions. Even less Mo was absorbed from an extrinsically labelled composite meal. The data obtained demonstra te a pattern of intestinal Mo absorption which is different from that of ot her essential trace metals, e.g., Fe or Co.