ESSENTIAL TRACE METALS IN MAN: MOLYBDENUM

A survey of human exposures to molybdenum, a trace metal essential for almost all forms of life, was made by analyzing human tissues of 381 subjects from around the world by emission spectroscopy, and foods and beverages by a colorimetric method. Molybdenum was present in all human livers, kidneys and adrenals examined. Total body content of United States subjects was less than 9 mg and most organs and tissues contained little. Unlike other essential trace metals, mean concentrations of molybdenum in liver and kidney were relatively low in the newborn, rising to a peak in the second decade of life and declining slightly thereafter. Mean hepatic and renal concentrations of United States and foreign subjects were similar, but the latter had more molybdenum and it occurred more frequently in other organs and tissues. Only a few correlations of molybdenum with other trace metals in tissues were significant. The daily intake of molybdenum in standard diets was about 350 μg. Fish and animal meats supplied variable amounts; legumes, whole grains and their products supplied the majority. Plant foods high in purines were usually high in molybdenum, whereas most vegetables had little or none. Molybdenum in wheat was depleted in refining to white flour; that in sugar was concentrated in molasses and syrups. Rats fed a diet low in molybdenum had higher serum uric acid levels than those given added molybdenum. There is evidence that dental caries may be prevented by a high intake of molybdenum. It is possible that renal xanthine calculi may result from low intakes and that molybdenum may somehow be involved in disturbances of uric acid metabolism.