Biokinetic studies in humans with stable isotopes as tracers. Part 1: A methodology for incorporation of trace metals into vegetables

The metabolism and biokinetics of trace metals in humans can be successfull y studied employing stable isotopes of the investigated elements as tracers . For the estimation of the bioavailability and the intestinal absorption f rom solid food, materials are required which have been intrinsically labell ed with the chosen stable tracer, since the use of an extrinsic label may l ead to erroneous results. Here a technique for producing intrinsically labelled Vegetables is present ed and optimized with regard to molybdenum, gadolinium and ruthenium, eleme nts of interest in the field of radiation protection and/or nutrition. Thes e feasibility studies were aimed to determine the most favourable condition s for the production of vegetables containing the selected tracers in amoun ts high enough to enable successful biokinetic studies in humans. In this o ptimization study the natural elements were used instead of the more expens ive stable isotopes. Mo is readily absorbed both into cress (Lepidium sativ um) and into french beans (Phaseolus vulg. var. nanus). Gd uptake into cres s is moderate, while Ru may be easily and succesfully incorporated only int o sprouts of mung beans (Vigna radiata).