Molybdenum is a silverish-white trace element with metallic properties. It is found most often in soils and is usually absorbed through the consumption of plant material. The human body contains about nine milligrams of molybdenum, with the highest concentrations found in the liver, kidneys, bones and skin.

Why do we need it?

Molybdenum is essential for the proper function of certain enzyme-dependent processes, including the metabolism of iron. It also forms part of several body enzymes and is needed to convert a substance called purine into uric acid.

Molybdenum has been used to treat copper toxicity in conditions such as Wilson's disease. Preliminary evidence has suggested that molybdenum might prevent certain types of asthma attacks. It has also been used with fluoride to treat dental decay.

How much molybdenum should I take?

There is currently no recommended daily allowance (RDA) for molybdenum. However, the National Academy of Sciences has deemed the following amounts to be safe and adequate in a normal diet:

• Adult men: between 75-250 micrograms/day
• Adult women: between 75-250 micrograms/day
• Children aged 7-10: between 50-150 micrograms/day
• Infants: between 15-40 micrograms/day
• Pregnant/lactating women: between 75-250 micrograms/day

What are some good sources of molybdenum?

Large amounts of molybdenum are found in milk, beans, dark green leafy vegetables, unrefined cereals and grains. Hard tap water can also supply molybdenum to the diet.

What can happen if I don't get enough molybdenum?

Molybdenum deficiency is virtually nonexistent in the U.S. and is usually seen only in people who have been on prolonged tube or intravenous feeding or have a genetic inability to metabolize molybdenum. Symptoms of deficiency include rapid heartbeat and breathing, headaches, night blindness, anemia, mental disturbances, nausea and vomiting. Some studies conducted in Japan and China have linked low levels of molybdenum with an increased risk of stomach and esophageal cancers.

What can happen if I take too much?

Molybdenum toxicity is extremely rare in the United States. Most health experts agree that an intake of as much as 15 milligrams per day is safe; however, large amounts can interfere with the absorption of copper. In rare cases, excessive molybdenum consumption can cause nausea, diarrhea, or gout-like symptoms such as joint pain and swelling.