Molybdenum Safety

Toxicity

The toxicity of molybdenum compounds appears to be relatively low in humans. Increased blood uric acid levels and gout-like symptoms have been reported in occupationally exposed workers in a copper-molybdenum plant and an Armenian population consuming 10 to 15 milligrams (mg) of molybdenum from food daily. In other studies, blood and urinary uric acid levels were not elevated by molybdenum intakes of up to 1.5 mg/day. There is one report of an acute toxic reaction associated with molybdenum from a dietary supplement. An adult male, reported to have consumed a total of 13.5 mg of molybdenum over a period of 18 days (300-800 mcg/day), developed acute psychosis with hallucinations, seizures, and other neurologic symptoms. However, a controlled study found no serious adverse effects of molybdenum intakes of up to 1.5 mg/day (1,500 mcg/day) for 24 days in four healthy young men.

The Food and Nutrition Board (FNB) of the Institute of Medicine found little evidence that molybdenum excess was associated with adverse health outcomes in generally healthy people. To determine the tolerable upper level of intake, the FNB selected adverse reproductive effects in rats as the most sensitive index of toxicity and applied a large uncertainty factor because animal data was used. Tolerable upper intake levels (UL) for molybdenum are listed by age group in the table below.

Tolerable Upper Intake Level (UL) for Molybdenum
Age Group	UL (mcg/day)
Infants 0-12 months	Not possible to establish*
Children 1-3 years	300
Children 4-8 years	600
Children 9-13 years	1,100 (1.1 mg/day)
Adolescents 14-18 years	1,700 (1.7 mg/day)
Adults 19 years and older	2,000 (2.0 mg/day)

*Source of intake should be from food and formula only.

Drug Interactions

High doses of molybdenum have been found to inhibit the metabolism of acetaminophen in rats. However, it is not known whether this occurs at clinically relevant doses in humans.

The RDA for molybdenum (45 mcg/day for adults) is sufficient to prevent deficiency. Although the intake of molybdenum most likely to promote optimum health is not known, there is presently no evidence that intakes higher than the RDA are beneficial. Most people in the U.S. consume more than sufficient molybdenum in their diets, making supplementation unnecessary. Following the Linus Pauling Institute's general recommendation to take a multivitamin/multimineral supplement that contains 100% of the daily values (DV) for most nutrients is likely to provide 75 mcg/day of molybdenum because the DV for molybdenum has not been revised to reflect the most recent RDA. Although the amount of molybdenum presently found in most multivitamin/mineral supplements is higher than the RDA, it is well below the tolerable upper intake level (UL) of 2,000 mcg/day and should be safe for adults.

See also: