Molybdenum

What molybdenum is

Molybdenum is an essential trace element. In the body it is built into the molybdenum cofactor, which several enzymes need, including sulfite oxidase. This enzyme neutralizes the sulfite that forms when sulfur-containing amino acids are broken down. The EU permits the claim that molybdenum contributes to normal sulfur amino acid metabolism.

EFSA gives an adequate intake for adults of 65 µg per day, the D-A-CH societies 50 to 100 µg. A small German survey found an average of 89 µg in women and 100 µg in men on a mixed diet. In the BK-Score, human evidence stands at 3 out of 10 points: the biochemistry is precisely understood; a benefit of additional supplements has not been studied. Another trace element with similarly well understood biochemistry is copper.

How it works

Molybdenum is absorbed very well from food: in isotope studies with young men it was 88 to 93 percent, at intakes between 22 and 1,490 µg per day. The amount in the body is regulated by the kidneys: at low intake molybdenum is conserved, at high intake the kidneys rapidly excrete the excess in the urine.

How decisive the cofactor is is shown by molybdenum cofactor deficiency type A, a rare inherited disease. Those affected lack the precursor cPMP; without functioning enzymes, toxic sulfite accumulates in the brain and damages it. Additional molybdenum does not help here. Since 2022, fosdenopterin, which replaces the missing precursor, has been approved in the EU.

What the studies show

Depletion diet: Turnlund 1995

Four young men ate a low-molybdenum diet with 22 µg per day for 102 days, then the same diet with 467 µg for 18 days. On the low diet they did not consistently reach a balance between intake and excretion, but this improved over time, and no signs of deficiency appeared. The authors estimated the minimum requirement at about 25 µg per day or less.

Five intake levels: Turnlund 1995 and Novotny 2007

The same research group gave four young men 22, 72, 121, 467 and 1,490 µg of molybdenum per day in succession, each for 24 days. No side effects occurred at any level, 88 to 93 percent was absorbed, and urinary excretion rose with increasing intake. The kinetic analysis showed that about 115 to 120 µg per day maintained the participants’ original plasma levels; their intake before the study was thus well above the US reference value of 45 µg.

Artificial nutrition: Abumrad 1981

The report describes an intolerance to amino acids during long-term intravenous nutrition that reversed with molybdate. We found no further reports of diet-related molybdenum deficiency in humans.

Case report on a supplement: Momcilović 1999

A man in his late thirties took a total of 13.5 mg of molybdenum from a supplement over 18 days, 300 to 800 µg per day. He developed an acute psychosis with hallucinations and seizures; the symptoms receded after chelation therapy, and a year later lasting cognitive impairments were found. A single report does not prove a causal link, but it stands in contrast to the symptom-free isotope studies with similar amounts.

Molybdenum cofactor deficiency: fosdenopterin (EMA 2022)

The European Commission approved fosdenopterin (Nulibry) on September 15, 2022, under exceptional circumstances, for patients with molybdenum cofactor deficiency type A. The medicine replaces the missing precursor cPMP, is given daily as an infusion and continued for life if the diagnosis is genetically confirmed. It is prescription-only.

Where the data stop

• Benefit of additional supplements. No controlled study has examined whether molybdenum has a benefit with a normal diet.
• Detoxification and sulfite intolerance. The role of sulfite oxidase is biochemically established; whether supplements improve sulfite breakdown in people without a deficiency has not been studied.
• Long-term safety. The controlled data cover 24 days each in 4 men.

Status, approval and legal

Molybdenum may be added to food supplements and foods. For this the BfR recommends maximum levels of 80 µg per recommended daily dose of a food supplement, 19 µg per 100 g of solid food and 5 µg per 100 ml of beverage. According to the former EU Scientific Committee on Food, the tolerable upper intake level is 600 µg per day for adults and 500 µg for 15- to 17-year-olds.

The EU has approved the claim for molybdenum that it contributes to normal sulfur amino acid metabolism. Fosdenopterin for molybdenum cofactor deficiency is a prescription-only medicine.

Safety

In the isotope studies, young men tolerated up to 1,490 µg per day for 24 days without side effects; the kidneys excreted the excess. Against this stands a single case report of psychosis with seizures on 300 to 800 µg daily from a supplement. The BfR derives its maximum level of 80 µg so that even people with a high dietary intake stay below the upper limit.

In the BK-Score, safety stands at 5 out of 10 points; this axis measures how well safety has been studied, not how safe the substance is. This text is information and does not replace medical advice.

Sources

• BfR – proposed maximum levels for molybdenum in foods including food supplements (2021)
• Turnlund JR et al., Am J Clin Nutr 1995 – depletion and repletion study, 4 young men, 102 days
• Turnlund JR et al., Am J Clin Nutr 1995 – isotope study, 4 young men, five intake levels from 22 to 1,490 µg
• Novotny JA, Turnlund JR, J Nutr 2007 – molybdenum kinetics at five intake levels
• Abumrad NN et al., Am J Clin Nutr 1981 – amino acid intolerance during long-term parenteral nutrition, reversed with molybdate
• Momcilović B, Arh Hig Rada Toksikol 1999 – case report, acute poisoning from a molybdenum supplement
• EMA – Nulibry (fosdenopterin), EPAR overview, EU approval 2022-09-15
• Regulation (EU) No 432/2012 – list of permitted health claims made on foods