Molybdenum is a referenced to as a ‘transition’ metal and very rare trace mineral. However its importance cannot be underestimated, as it is essential for all living things. Molybdenum is located throughout our bodies in various tissues, cells, and boney structures. It is used as a cofactor in three particular enzymes, all of which are important in the chemical transformations occurring in the carbon, nitrogen, and sulfur cycles.  In humans, molybdenum also function as a cofactor for three specific enzymes:
- Sulfite oxidase - responsible for metabolizing sulfur-containing amino acids for uses in the body.
- Xanthine oxidase - breaks down nucleotides; the precursors to our genetic codes (DNA and RNA). The byproduct of this reaction is uric acid. Because of this chemical reaction, uric acid may provide for antioxidant capabilities in our blood and lymphatic systems.
- Aldehyde oxidase - in association with xanthine oxidase, this enzyme helps to metabolize certain toxins and drugs ingested in the human body.
Currently, researches have indicated that sulfite oxidase is the only enzyme, of the before mentioned three, that humans cannot survive without.  All of the enzymes and their associated properties are vital in the overall growth and health of humans.
The content of molybdenum in plant sources varies in regards to the amount present in the soil, and accompanying environmental conditions.  Because the molybdenum content in food sources is so inconsistent, a food graph is omitted. The richest sources of molybdenum are legumes. Legumes include foods such as lentils, peas and beans. Although vegetable, animal, and fruit sources contain molybdenum, the amounts are inadequate in fulfilling one’s daily dietary intake of this trace mineral and should not be counted upon as reliable sources.
Molybdenum’s clinical applications are relatively minor because it is classified as one of the rarest minerals on earth. Knowing this, its abilities to prevent, treat, and cure illnesses in the human body are still being researched. As mentioned, we know that molybdenum is a critical mechanism in the metabolic processes of three specific enzymes; one of which being fundamental to our survival. We also know that through nitrogen reduction it plays an important role in the detoxification of the liver by various means, usually nitrogen degradation, and assists in the maintenance of the health of cells in the body.
This rare mineral has also been studied in regards to the overall effect it provides for our dental structures. Research has paralleled molybdenum decrease to an increased incidence of dental cavities and tooth-related disorders (dental caries).  This may result from its ability to break down sulfite toxin build-ups throughout the body.
Many of the protein rich foods we consume contain sulfites. Sulfites are found in many preservatives added to carbohydrate and fatty foods as well. Cavity formation (and other tooth and gum disorders) may be directly dependant upon our ability to break down these sulfites to prevent toxic build-up, assisting in proper dental hygiene.
Because of molybdenum’s has an assumed role as an antioxidant, cancer studies have applied the supplementation of molybdenum in relation to various forms of this disease.  An increased dietary intake of nitrosamines, a carcinogen (a substance that causes cancer), may be directly linked to two specific types of cancer: gastroesophageal and gastrointestinal cancers.
In Linxian, China for example, due to the low mineral content (esp. molybdenum) of the soil where various food sources are harvested, individuals in this area were 100 times more prone to develop a malignant form of the abovementioned cancers than an average American.  In addition, combinations of different nutritional supplements provided for no greater effect on reducing the outcome or preventing the likelihood of one developing cancer in this region of China. The link between low mineral content in soil and the onset of cancer has also been witnessed in the United States. 
Molybdenum may be administered orally, parentally, or via injection (intravenously).
Both the recommended dietary intakes (RDA) and adequate daily intakes have been established for this mineral. The RDA for molybdenum was recently revised in January of 2001; expressed below in micrograms (mcg) per day:
|0-6 months||2 mcg/day|
|7-12 months||3 mcg/day|
|1-3 years||17 mcg/day|
|4-8 years||22 mcg/day|
|9-13 years||34 mcg/day|
|14-18 years||43 mcg/day|
|19 years +||45 mcg/day|
|Pregnancy and Breastfeeding||50 mcg/day|
Tolerable upper level intakes of molybdenum have also been established by the Food and Nutrition Board (FNB) of the Institute of Medicine. Intakes are expressed as ULs and are listed by age group. 
|Age Group||ULs (mcg/day)|
|Children 1-3 years||300|
|Children 4-8 years||600|
|Children 9-13 years||1,1000 (1.1 mg/day)|
|Adolescents 14-18 years||1,7000 (1.7 mg/day)|
|Adults 19 years and older||2,000 (2 mg/day)|
A deficiency of this trace mineral is extremely rare. There has never been a reported deficiency in a healthy individual. However, it is theorized that the lack of molybdenum in a human nutrition may result in the incorrect metabolizing of certain enzymes.
Deficiency may also result as a result of prolonged periods of parental nutrition with a lack of molybdenum in solution; deficiency states are also known to occur in individuals suffering from Crohn’s disease. 
Other persons at risk for the development of a deficiency include those with inborn errors of metabolism. Two specific forms of a deficiency have been recognized: isolated sulfite oxidase deficiency and molybdenum cofactor deficiency. Both affect the metabolism of the vital oxidase compound.
Toxicity may occur in individuals consuming abnormally large dosages, as much as 10 -15 milligrams daily.  Although the risk of overdose is low, signs include; gout-like symptoms, increased blood uric acid levels, acute psychosis (with hallucinations), seizures, and other neurological disorders. 
Other potential compounds that may contribute to the onset of molybdenum toxicity include; molybdenum dusts, molybdenum trioxide, and water-soluble molybdates. These compounds can result in toxicity if inhaled or ingested, due to the presence of metallic content.
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