Molybdenum (Mo) is an essential nutrient for animals and humans.
Tissue content of molybdenum is low, with the highest concentrations in
the liver, kidney, adrenal gland and bone. It is a component of a number
of enzymes, including sulfite oxidase (involved in the metabolism of
sulfur amino acids), xanthine oxidase (involved in the oxidation of
purines and pyrimidines and the production of uric acid), and aldehyde
oxidase (involved in the oxidation of aldehydes). These enzymes share a
common "molybdenum cofactor."
Deficiencies: Molybdenum deficiency is extremely rare
and has only been identified in the presence of other serious disorders.
Metabolic defects in the molybdenum cofactor are characterized by the
absence of the three molybdoenzymes. Both the deficiency and the metabolic
disorders are accompanied by abnormal excretion of sulfur metabolites, low
uric acid concentrations, and elevated hypoxanthine and xanthine
excretion. The absence of sulfite oxidase in the metabolic disorder leads
to death at an early age.
Diet recommendations: The Estimated Safe and Adequate
Dietary Intakes of molybdenum (µg/day) are: 15-30 at age 0-6 months, 20-40
for 6-12 months, 25-50 for 1-3 years, 30-75 for 4-6 years, 50-150 for 7-10
years, and 75-250 for adolescents and adults. This range is based on the
usual dietary intake, about 75 to 240 µg/day by adults. The range was
extrapolated for other age groups on the basis of body weight.
Food sources: Rich sources of molybdenum include
legumes, cereal products, and leafy vegetables. The amount in foods
depends on the soil molybdenum content. Molybdenum is very well absorbed,
but its bioavailability may be affected by some food components.
Toxicity: Molybdenum toxicity is much more likely than
deficiency. Toxicity is common in cattle grazing in pastures with high
molybdenum soil. A high incidence of gout has been reported in humans with
intakes of 10-15 mg/day.
Recent research: Controlled studies in humans suggest
that the molybdenum requirement is well below the usual dietary intake,
which is consistent with lack of molybdenum deficiency in the US
population. Bioavailability studies suggest that molybdenum is less well
absorbed from soy products than from leafy vegetables
