Molybdenum is an essential mineral needed by the body in very small quantities. While often overlooked, this mineral is found in trace amounts in many everyday foods. In fact, molybdenum is found in such a wide variety of foods that most people do not have to make any dietary modifications to obtain the recommended dosage.
Molybdenum is a key component of several necessary enzymes in the human body. It is involved in the formation of uric acid and helps the body to utilize iron. It aids in the breakdown of sulfur-containing amino acids. It also helps regulate the metabolism of copper, magnesium and calcium. Molybdenum is stored primarily in the liver, adrenal glands and kidneys, but is found in varying concentrations in tissue throughout the body. The total amount of molybdenum stored in the human body is about 9 mg.
Most plants that grow above ground are good sources of molybdenum. The richest sources are legumes, including beans, peas, lentils and soybeans. Nuts, leafy vegetables and grains like oats, wheat and rice and also contain ample amounts of the mineral. The amount of molybdenum in plants will vary depending on the mineral content of the soil in which it is grown. Animal sources of molybdenum include liver, eggs and milk.
The U.S. recommended daily allowance of molybdenum for adults is 45 mcg per day. Molybdenum deficiency is rare in people who eat a balanced diet. Deficiency is usually only seen in patients on intravenous feeding or in conjunction with several genetic disorders that prevent the absorption of the mineral. Symptoms of deficiency include anemia, rapid heartbeat, fatigue, dizziness and sulfite sensitivity.
Some researchers believe that molybdenum in food may protect against certain forms of cancer. In the September 1995 issue of Archives of Environmental Health, a study by Dr. Hiroto Nakadaira found that mortality rates from esophageal and rectal cancer were highest in regions where soil concentrations of molybdenum are low. It is theorized that molybdenum in the soil keeps plants from producing compounds called nitrosamines, a known carcinogen. Further research is needed to determine whether a diet high in molybdenum plays a role in cancer prevention.
Toxicity of molybdenum is relatively low. Doses in excess of 10 mg per day can lead to gout-like symptoms, such as swelling of the joints, due to increased uric acid production. It can also hinder the body's ability to absorb copper. It is difficult to reach harmful molybdenum levels through diet alone. Most cases of toxicity result from excessive intake of molybdenum supplements. People who consume diets high in legumes and grains may wish to avoid supplements and multivitamins containing molybdenum.