What is Molybdenum?
Molybdenum (Mo), an important trace mineral for all living organisms, functions as a cofactor for numerous enzymes that catalyze vital chemical transformations in the nitrogen and sulfur cycles.
The molybdenum-dependent enzymes are not only needed for the health of living organisms but for the overall life of the ecosystem.
Along with the other transition metal elements Tungsten, Manganese, Iron, Copper, Nickel, Cobalt, and Zinc, they serve as structural glue, osmotic regulators, and as catalytic centers for numerous cellular reactions. The worth of metals in terms of biological catalysis is emphasized by the fact that one-third or more of all characterized enzymes are metalloenzymes (metal-containing enzymes). Therefore, metals have an important role in all the facets of bacterial metabolism.
By mediating a large number of vital reactions in the elemental cycles, bacterial metalloenzymes utilize a chief catalytic energy on the biosphere. Since microorganisms are the main players in terms of recycling hydrogen, oxygen, carbon, nitrogen and sulfur on the surface of the Earth, bacterial enzymes that contain molybdenum, iron, nickel, copper, and manganese are, by transference, the agents that are responsible in the cycling of the said elements. Molybdenum’s biological form is present in almost all molybdoenzymes (molybdenum-containing enzymes), the molybdenum cofactor, which is primarily an organic molecule.
The regulation of the transport of molybdate has been studied intensely and import of the mineral is known to occur through inducibleABC-type transporters, with transport also occurring through sulfate uptake systems and nonspecific anion transporters (reviewed by Self et al, 2001). A diversity of archaea and bacteria can reduce molybdenum (VI) to molybdenum (V) via anaerobic and aerobic conditions. However, the prokaryotic Mo reduction mechanisms are not known.
The only known event of acquired molybdenum deficiency happened in a patient diagnosed with Crohn’s disease on long-term total parenteral nutrition (TPN), wherein molybdenum was not added to the TPN solution. Headache, night blindness, rapid heart and respiratory rates, and ultimately became comatose were the known molybdenum deficiency symptoms developed by the patient. He had also demonstrated molybdenum deficiency biochemical signs such as decreased urinary excretion of uric acid and sulfate, low plasma uric acid levels, and increased urinary excretion of sulfite.
The clinical condition of this patient improved and showed the disappearance of amino acid intolerance when he was supplemented with molybdenum (160 mcg/day) and the TPN solution was discontinued. Similar mineral deficiency symptoms have been observed in children who are known to have molybdenum cofactor deficiency.
Molybdenum toxicity appears to be very low in humans. However, possible symptoms include seizures, hallucinations, and other neurologic symptoms; these can occur when taken in very large doses.
The recommended dietary allowance (RDA) is:
|0 to 6 months||2 AI||2 AI|
|7 to 12 months||3 AI||3 AI|
|1 to 3 years||17||17|
|4 to 8 years||22||22|
|9 to 13 years||34||34|
|14 to 18 years||43||43|
|19 years and older||45||45|
|Pregnant (all ages)||50||–|
|Lactating (all ages)||50||–|
Molybdenum Food Sources
An annual survey of the mineral content in the typical American diet, known as The Total Diet Study, has shown that the average daily intake of molybdenum is well above the RDA for molybdenum, as it averages 109 mcg/day for men and 76 mcg/day for women.
Some of the major molybdenum food sources include legumes such as lentils, peas, and beans (these are the highest sources of this trace mineral), while nuts and grain products are known to be molybdenum rich foods. Some foods that have generally low molybdenum content include animal products and several fruits and vegetables. Due to the fact that plants molybdenum content depends upon the molybdenum content of the soil and other conditions in the environment, the content of this mineral in foods can vary considerably.