The European food safety authority (EFSA) last evaluated vitamins and minerals for safety in 2006 and set a so-called Tolerable Upper Intake Level (UL) for each micronutrient, provided sufficient data were available. This UL reflects the maximum safe level of a micronutrient that will not cause adverse effects when taken daily from all sources for a lifetime.
| The maximum safe daily intake for molybdenum is 600 µg. The maximum safe daily intake for molybdenum is 12 times the EU recommended daily intake (Nutrient Reference Value, NRV). |
The above safe maximum daily intake applies to adult men and women 18 years of age and older, as well as pregnant and lactating women.
Estimates of intakes of molybdenum in the Federal Republic of Germany indicate that the maximum safe daily intake for molybdenum is not reached. Molybdenum amounts of 1.5 mg (1,500 µg) per day, taken over 24 days, remained without undesirable side effects.
The NOAEL (No Observed Adverse Effect Level) – the highest dose of a substance that has no detectable and measurable adverse effects, even with continued ingestion – was set by EFSA at 0.9 mg of molybdenum per kg of body weight, which is approximately 100 times the safe daily limit for molybdenum in a person weighing 70 kg.
Adverse effects of excessive molybdenum intake include diarrhea (diarrhea), anemia (anemia), and hyperuricemia (increased uric acid concentrations in the blood – a risk factor for gout), as well as painful joints and even gout (uricopathy). Higher molybdenum intake in humans is associated with an increased incidence for gout and damage to the liver.
In a region in Armenia with very molybdenum-rich soils, gout-like symptoms with arthralgia (joint pain) were observed. It has been estimated that daily intakes of 10-15 mg of molybdenum there for 1 to 5 years resulted in hyperuricemia (elevation of uric acid levels in the blood) and hyperuricosuria (increased uric acid excretion in the urine).
In animal studies in rats, amounts of 2 to 8 mg molybdenum per kg body weight per day resulted in growth disturbances. At levels of 1.6 to 2 mg molybdenum per kg body weight per day, changes in reproduction and development were observed. Acute signs of poisoning occurred at levels of 5 mg (5,000 µg) molybdenum per kg body weight and above.