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Molybdenum - Mineral


Molybdenum is an essential constituent of two enzymes found in humans: xanthine oxidase, which is involved in uric acid formation, and aldehyde oxidase, which catalyzes the chemical oxidation of aldehydes.

Molybdenum is concentrated primarily in the liver, kidney, bone, and skin. There is estimated to be approximately nine milligrams of molybdenum in the adult human body.

Molybdenum is an antagonist to copper absorption, as is copper to molybdenum absorption. Excess molybdenum intake can induce copper deficiencies with the subsequent symptoms.

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Method of Action

Molybdenum is an important constituent of aldehyde oxidase and xanthine oxidase. Aldehyde oxidase catalyzes the oxidation of an aldehyde functional group to the corresponding carboxylic acid. Xanthine oxidase catalyzes the oxidation of xanthine to uric acid for excretion. Xanthine is a product formed in the chemical degradation of purine nucleotides found in DNA and RNA.

Molybdenum, in the presence of inorganic sulfate, tends to reduce copper absorption and retention. Several theories for why this antagonistic relationship occurs have been postulated. There is evidence that copper and molybdenum form an insoluble complex called lingrenite, which cannot be absorbed easily. Other theories include the postulated interference of ceruplasm synthesis: ceruplasm is a protein necessary for copper transport into blood.

Molybdenum absorption occurs readily in gastrointestinal tract, and excretion occurs primarily via the urine.

Properties and Uses

Molybdenum has been implicated as a possible contributor to decreased incidence of dental carries, a reduced incidence of cancer, and a bringing into balance of female hormones for the control of premenstrual syndrome.

Consequences of Deficiency

Molybdenum deficiencies in humans have not been conclusively linked to any specific set of symptoms; however, one source indicates that a high incidence of cancer of the esophagus may be the result of low molybdenum intake.

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Toxicity Levels

Symptoms of molybdenum toxicity include diarrhea, depressed growth rate, and anemia. Gout-like symptoms may result from excessive intake.

High levels of molybdenum intake can induce a high rate of copper excretion (due to the antagonistic effect the two minerals have on each other), which could possibly result in a copper deficiency.

A high intake of molybdenum can alter the activity of alkaline phosphatase, resulting in certain bone abnormalities. Alkaline phosphatase enzymatically releases phosphate groups from the molecule glucose 1-phosphate, thereby producing high levels of inorganic phosphate; phosphate is necessary to produce hydroxyapatite crystals in bone.

Recommended Dietary Allowances

The RDA for adults is from 0.15 to 0.5 mg. The RDA for children is not yet established, but is a relatively small amount.

Food Sources

Barley Beef Kidney Beef Liver Buckwheat
Hot Cocoa Eggs Legumes Milk
Yams Oat Flakes Potatoes Rye Bread
Spinach Sunflower Seeds Wheat Germ Green Leafy Vegetables
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