Molybdenum is essential

An element is considered essential when it is required for growth and function by living organisms. Molybdenum features as one of the elements in the list of essential metals: cobalt, copper, iron, magnesium, manganese, molybdenum, selenium, and zinc.

During evolution of life on earth, molybdenum played a crucial role in converting inorganic nitrogen via ammonia to organic nitrogen, amino acids, nucleotides, proteins, DNA and RNA, the molecules of life.

Molybdenum is essential for human, animal and plant life. It is a cofactor for a number of enzymes that catalyze chemical transformations in the global carbon, nitrogen and sulfur cycles. Thus, molybdenum-dependent enzymes are not only required for human health, but also for the health of the entire ecosystem.

Molybdenum is found in combination with sulfur in the mineral molybdenite and with oxygen as naturally occurring molybdate in oceans, rivers and soils. The concentration of molybdenum in the environment is variable, typically a few parts per million.

In humans, molybdenum is an essential constituent of several enzymes which play a vital role in bodily processes.

The ability of the human body to eliminate waste is fundamental to our physical well-being. Molybdenum is an essential constituent of enzymes needed for digestion and excretion.

In humans, molybdenum is needed in enzymes which manage chemical reactions of sulfur and nitrogen compounds in the body, helping to metabolize toxins.

The enzymes are:

Xanthine oxidase, which regulates the production of uric acid. Low dietary molybdenum, and a deficiency or absence of xanthine oxidase can lead to kidney stones and possible renal failure. 

Aldehyde oxidase, which in humans is needed for a number of important processes and is thought to be involved in: 

• steroid hormone synthesis
• vitamin A metabolism
• maintaining lung function
• maintaining healthy blood circulation

Sulfite oxidase, which is necessary for the metabolism of sulfur amino acids. Without it, in very rare genetic cases,  neurological problems can develop.

Molybdenum must be ingested from food or water. Good sources of molybdenum include lentils, nuts, wholegrains, beans, cows’ milk, peas, cauliflower, and leafy green vegetables such as spinach and kale. The molybdenum content in foods depends in part on its content in the soil, which can vary considerably. The recommended dietary allowance (RDA) for molybdenum is 45 μg daily for an adult.

As an essential trace element, molybdenum is commonly found in over the counter dietary supplements which usually supply about 50 µg of molybdenum per day, although normal food and water intake should supply an individual’s nutritional requirement.

Either a lack or excess of essential elements can be deleterious to health. If there is too little, the effect is nutritional deficiency. If there is too much, there may be toxicity.

The tolerable upper intake of molybdenum for adults is 2000 µg per day, however this is highly unlikely in normal circumstances.

Dietary molybdenum intakes around the world vary widely from 20 μg/day to 560 μg/day due to the molybdenum content of the soils in which foods are grown.

In normal dietary intake, molybdenum does not accumulate in the human body as excess is excreted.

The human body operates a homeostatic mechanism which regulates levels of molybdenum, and other essential elements, in order to keep levels within an optimal range.

Molybdenum deficiency is not known to occur in healthy people. A very small number of babies are born with a molybdenum cofactor deficiency which can lead to neurological disorders and ultimately to early death.  This is a rare genetic disease which results in deficiency of all molybdoenzymes.

Molybdenum is no different from other elements in being harmful at excessive concentrations. The amount of molybdenum needed to be harmful is much greater than for many other common elements. Molybdenum, although one of the higher density metals,  is not to be confused with those so-called ‘heavy metals’ which are recognized as toxic.

Tetrathiomolybdate – a molybdenum compound – is used to control copper levels in the treatment of Wilson’s disease, a genetic disorder where the individual cannot metabolize copper. Wilson’s disease is characterized by copper accumulation in tissues responsible for hepatic and neurologic functions leading to adverse effects.

Some molybdenum compounds have been trialed in patients with advanced cancers, with the aim of preventing disease progression or relapse. Pilot trials have shown promising results in the treatment of metastatic kidney and colorectal cancer as well as breast cancer.

Molybdenum is essential in enzymes which enable plants to utilize nitrogen from the air and from nitrate fertilizers.

Molybdenum deficiency in soil is detrimental to plant growth, as it causes nitrogen deficiency.

In Australia, molybdenum deficiency has been identified as the second most common micronutrient deficiency affecting large areas of acid soil cropland and lack of molybdenum can impair yield in cereal crops by as much as 30%. In China, molybdenum deficiency affects nearly half of all agricultural soils and has been identified as an important factor limiting yields of winter wheat and soya. A study in Egypt demonstrated that the addition of molybdenum to mandarin trees increased fruit yield by 37%.

In animals, as in humans, molybdenum is needed in enzymes which manage chemical reactions of sulfur and nitrogen compounds in the body, helping to metabolize toxins.  

Molybdenum also influences protein synthesis, and the metabolism of phosphorus, sulfur, potassium, iron, copper, zinc, and iodine. With some animals (chicks, red trout) added dietary molybdenum stimulates growth.

Ruminant animals such as cows and sheep have different digestive mechanisms from humans and can be susceptible to molybdenum accumulation. In areas where the pasture and forage are rich in molybdenum, ruminant animals can be at risk of developing molybdenosis – a molybdenum-induced form of copper deficiency – which can be remedied with copper supplementation.