Transcript :
Transcript :
Promo)
You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry.
(End promo)
Meera Senthilingam
This week, we clarify the importance of the often misunderstood molybdenum. Here's Quentin Cooper:
Quentin Cooper
The answer to the ultimate question - of life, the Universe and Everything - is, as every Douglas Adams fan knows, 42. And 42, as every Mendeleev fan knows, is the atomic number of molybdenum. And for many that - plus the indisputable fact that molybdenum is a funny word - is often about as far as their knowledge goes of this silvery metal - not that they'd have known it was a silvery metal - which is wedged between its better known brethren chromium and tungsten in group six of the periodic table. That odd-sounding name comes in a convoluted way from the Greek for lead, as ores of the two were often mixed up by early mineralogists - it was also frequently mistaken for graphite - and it wasn't until 1778 that molybdenum was recognised as a distinct entity deserving its own place in the periodic table, and a few years later still that it was finally isolated. The key breakthrough came from the Swedish chemist Carl Wilhlelm Scheele, better known as 'Hard luck Scheele' because he made a whole series of chemical discoveries, including oxygen, only for others to go and get the credit.
So its mistaken-identity history, its miscredited discoverer, its misleading and often mis-spelled name, all add to the aura of comedy and confusion around molybdenum.....and yet it's an element that's right at the root of life - not just human life, but pretty much all life on the planet: yes you'll find tiny amounts of it in everything from the filaments of electric heaters to missiles to protective coatings in boilers, and its high performance at high temperatures mean it has a range of commercial applications: it's useful in toughening up steel and giving it more corrosion resistance, as a catalyst in processes such as refining petroleum, and above all it's turned to when you need things to get hot but stay slippy - where WD40 and other petroleum derived oils are at risk of igniting, molybdenum sulfides are the basis of a range of lubricants which can cope with the heat and keep things moving smoothly.
But for all the ways we've discovered to use it, of far greater significance - although involving far smaller quantities of molybdenum - is the way we've evolved to make use of it within us. It's found in dozens of enzymes... including all important nitrogenase, which allows the most abundant element in the atmosphere, nitrogen, to be taken up and turned into compounds that enable bacteria, plants, us and everything between to synthesise and utilise proteins. Without proteins there wouldn't be much at all in the way of life....and without molybdenum there wouldn't be much at all in the way of proteins. And it turns up in other key human enzymes too such as xanthine oxidase in the liver, which is vital to our waste processing.
But just in case anyone's thinking of rushing off to buy one of the many commercially available trace mineral supplements with molybdenum it's worth adding that although like much of life on Earth we definitely need it.... we don't need that much of it: about a third of a gram is all you'll get through in an entire lifetime. That's next to nothing...but without it we'd be next to nothingness.
So, time to stop laughing at the funny name... molybdenum really is one of life's few true essentials.
Meera Senthilingham
So time to give some much-owed respect, it seems, to the element molybdenum. That was science broadcaster Quentin Cooper with the widely applied chemistry of molybdenum. Now, next week, blink and you may miss it.
Brian Clegg
If elements were insects, darmstadtium would be the mayfly of the chemical world. It exists for the most fleeting time before it transforms to something else. Darmstadium is never going to have a practical use - but its sheer brevity of existence gives it a wistful fascination.
Meera Senthilingham
And to find out what does happen in darmstadtium's brief existence on earth, in next week's Chemistry in its element. Until then, I'm Meera Senthilingham and thank you for listening.
(Promo)
Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists.com . There's more information and other episodes of Chemistry in its element on our website at chemistryworld.org/elements
(End promo)
This is a fact sheet intended for health professionals. For a general overview, see our consumer fact sheet.
Molybdenum is an essential trace element that is naturally present in many foods and is also available as a dietary supplement. Molybdenum is a structural constituent of molybdopterin, a cofactor synthesized by the body and required for the function of four enzymes: sulfite oxidase, xanthine oxidase, aldehyde oxidase, and mitochondrial amidoxime reducing component (mARC). These enzymes metabolize sulfur-containing amino acids and heterocyclic compounds including purines and pyrimidines [1,2]. Xanthine oxidase, aldehyde oxidase, and mARC are also involved in metabolizing drugs and toxins [3-6].
Molybdenum appears to be absorbed via a passive nonmediated process, though where absorption occurs in the intestinal tract is not known [1]. Adults absorb 40% to 100% of dietary molybdenum [2,7-10]. Infants absorb almost all of the molybdenum in breast milk or formula [11,12].
The kidneys are the main regulators of molybdenum levels in the body and are responsible for its excretion [1,2]. Molybdenum, in the form of molybdopterin, is stored in the liver, kidney, adrenal glands, and bone [2,7,13].
Because molybdenum deficiency is rare [14], molybdenum status is not assessed in clinical settings. According to a small study of 30 healthy men and women, serum levels of molybdenum range from 0.28 ng/mL to 1.17 ng/mL, and their average is 0.58 ng/mL [15]. In another small study of four healthy young men, plasma levels of molybdenum reached 6.22 ng/mL with a molybdenum intake of 1,490 mcg per day for 24 days [10]. The average concentration of urinary molybdenum is 69 ng/mL, but urinary molybdenum does not reflect molybdenum status [1].
Intake recommendations for molybdenum and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the National Academies of Sciences, Engineering, and Medicine [1]. DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and sex, include the following:
The basis for the EAR for molybdenum consists of two carefully controlled balance studies in a total of eight young men. The EAR for children and adolescents is extrapolated from adult values. Table 1 lists the current RDAs for molybdenum [1].
Table 1: Recommended Dietary Allowances (RDAs) for Molybdenum [1] Age Male Female Pregnancy Lactation Birth to 6 months 2 mcg* 2 mcg* 7–12 months 3 mcg* 3 mcg* 1–3 years 17 mcg 17 mcg 4–8 years 22 mcg 22 mcg 9–13 years 34 mcg 34 mcg 14–18 years 43 mcg 43 mcg 50 mcg 50 mcg 19+ years 45 mcg 45 mcg 50 mcg 50 mcg *AI, based on mean molybdenum intakes of infants fed primarily human milk.*AI, based on mean molybdenum intakes of infants fed primarily human milk.
Legumes are the richest sources of molybdenum [16]. Other foods high in molybdenum include whole grains, nuts, and beef liver [1,14,17,18].
The top sources of molybdenum in U.S. diets are legumes, cereal grains, leafy vegetables, beef liver, and milk [17]. Milk and cheese products are the main sources of molybdenum for teens and children [19].
The amount of molybdenum in food depends on the amount of molybdenum in the soil and in the water used for irrigation [1,2]. Drinking water generally contains only small amounts of molybdenum [17]. However, according to 2017 data from the U.S. Environmental Protection Agency, 0.8% of drinking water samples had molybdenum levels above 40 mcg/L [20]. The U.S. Department of Agriculture’s (USDA’s) FoodData Central [21] does not list the molybdenum content of foods or provide lists of foods containing molybdenum. Therefore, the amount of information on molybdenum levels in foods is quite limited.
Table 2: Molybdenum Content of Selected Foods [19] Food Micrograms*DV = Daily Value. The U.S. Food and Drug Administration (FDA) developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet. The DV for molybdenum is 45 mcg for adults and children age 4 years and older [22]. FDA does not require food labels to list molybdenum content unless molybdenum has been added to the food. Foods providing 20% or more of the DV are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet.
Molybdenum is available in dietary supplements containing molybdenum only, in combination with other minerals, and in multivitamin/mineral products. Amounts range from about 50 mcg to 500 mcg. Forms of molybdenum in dietary supplements include molybdenum chloride, sodium molybdate, molybdenum glycinate, and molybdenum amino acid chelate [23]. No studies have compared the relative bioavailability of molybdenum from these different forms.
Most Americans appear to consume adequate amounts of molybdenum. Although national surveys no longer collect data about molybdenum intake, FDA’s 1984 Total Diet Study estimated that average daily molybdenum intakes from foods were 109 mcg in men and 76 mcg in women [24]. According to the 1988–1994 National Health and Nutrition Examination Survey, molybdenum intakes from dietary supplements averaged 23 mcg/day for men and 24 mcg/day for women [25]. Intakes of molybdenum from drinking water collected from the 100 largest cities in the United States are estimated to be about 3 mcg/day based on intakes of 2 liters of water per day [26].
Molybdenum deficiency has not been reported, except in people with a genetic mutation that prevents the synthesis of molybdopterin and therefore of sulfite oxidase [14]. In this rare metabolic disorder, known as molybdenum cofactor deficiency, mutations in one of several genes prevent the biosynthesis of molybdopterin. The absence of molybdopterin impairs the function of enzymes that metabolize sulfite, leading to encephalopathy and seizures [1,14,27-29]; the neurological damage is severe and usually leads to death within days after birth [18,30].
A single reported incident of acquired molybdenum deficiency occurred in 1981 in a patient receiving total parenteral nutrition that was devoid of molybdenum. The patient developed tachycardia, tachypnea, headache, night blindness, and coma. These effects resolved with molybdenum administration [1,31].
No known groups of people are likely to have inadequate molybdenum intakes.
Molybdenum is not a standard treatment for any disease or disorder.
Acute molybdenum toxicity is rare, but it can occur with industrial mining and metalworking exposure. In healthy people, consumption of a diet high in molybdenum usually does not pose a health risk because the molybdenum is rapidly excreted in urine [1,14,18]. One study assessed the effect of high dietary intakes of molybdenum (10–15 mg/day) in an area of Armenia where the soil contains very high levels of molybdenum. The affected individuals experienced achy joints, gout-like symptoms, and abnormally high blood levels of uric acid [14].
Given the absence of human studies, the FNB established ULs for molybdenum for healthy individuals based on levels associated with impaired reproduction and fetal development in rats and mice [1].
Table 3: Tolerable Upper Intake Levels (ULs) for Molybdenum [1] Age Male Female Pregnancy Lactation Birth to 6 months None established* None established* 7–12 months None established* None established* 1–3 years 300 mcg 300 mcg 4–8 years 600 mcg 600 mcg 9–13 years 1,100 mcg 1,100 mcg 14–18 years 1,700 mcg 1,700 mcg 1,700 mcg 1,700 mcg 19+ years 2,000 mcg 2,000 mcg 2,000 mcg 2,000 mcg* Breast milk, formula, and food should be the only sources of molybdenum for infants.
Molybdenum has no known, clinically relevant, interactions with medications.
The federal government's 2020–2025 Dietary Guidelines for Americans notes that "Because foods provide an array of nutrients and other components that have benefits for health, nutritional needs should be met primarily through foods. ... In some cases, fortified foods and dietary supplements are useful when it is not possible otherwise to meet needs for one or more nutrients (e.g., during specific life stages such as pregnancy)."
For more information about building a healthy dietary pattern, refer to the Dietary Guidelines for Americans and the USDA's MyPlate.
The Dietary Guidelines for Americans describes a healthy dietary pattern as one that
This fact sheet by the National Institutes of Health (NIH) Office of Dietary Supplements (ODS) provides information that should not take the place of medical advice. We encourage you to talk to your health care providers (doctor, registered dietitian, pharmacist, etc.) about your interest in, questions about, or use of dietary supplements and what may be best for your overall health. Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice.
Promo)
You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry.
(End promo)
Meera Senthilingam
This week, we clarify the importance of the often misunderstood molybdenum. Here's Quentin Cooper:
Quentin Cooper
The answer to the ultimate question - of life, the Universe and Everything - is, as every Douglas Adams fan knows, 42. And 42, as every Mendeleev fan knows, is the atomic number of molybdenum. And for many that - plus the indisputable fact that molybdenum is a funny word - is often about as far as their knowledge goes of this silvery metal - not that they'd have known it was a silvery metal - which is wedged between its better known brethren chromium and tungsten in group six of the periodic table. That odd-sounding name comes in a convoluted way from the Greek for lead, as ores of the two were often mixed up by early mineralogists - it was also frequently mistaken for graphite - and it wasn't until 1778 that molybdenum was recognised as a distinct entity deserving its own place in the periodic table, and a few years later still that it was finally isolated. The key breakthrough came from the Swedish chemist Carl Wilhlelm Scheele, better known as 'Hard luck Scheele' because he made a whole series of chemical discoveries, including oxygen, only for others to go and get the credit.
So its mistaken-identity history, its miscredited discoverer, its misleading and often mis-spelled name, all add to the aura of comedy and confusion around molybdenum.....and yet it's an element that's right at the root of life - not just human life, but pretty much all life on the planet: yes you'll find tiny amounts of it in everything from the filaments of electric heaters to missiles to protective coatings in boilers, and its high performance at high temperatures mean it has a range of commercial applications: it's useful in toughening up steel and giving it more corrosion resistance, as a catalyst in processes such as refining petroleum, and above all it's turned to when you need things to get hot but stay slippy - where WD40 and other petroleum derived oils are at risk of igniting, molybdenum sulfides are the basis of a range of lubricants which can cope with the heat and keep things moving smoothly.
But for all the ways we've discovered to use it, of far greater significance - although involving far smaller quantities of molybdenum - is the way we've evolved to make use of it within us. It's found in dozens of enzymes... including all important nitrogenase, which allows the most abundant element in the atmosphere, nitrogen, to be taken up and turned into compounds that enable bacteria, plants, us and everything between to synthesise and utilise proteins. Without proteins there wouldn't be much at all in the way of life....and without molybdenum there wouldn't be much at all in the way of proteins. And it turns up in other key human enzymes too such as xanthine oxidase in the liver, which is vital to our waste processing.
But just in case anyone's thinking of rushing off to buy one of the many commercially available trace mineral supplements with molybdenum it's worth adding that although like much of life on Earth we definitely need it.... we don't need that much of it: about a third of a gram is all you'll get through in an entire lifetime. That's next to nothing...but without it we'd be next to nothingness.
So, time to stop laughing at the funny name... molybdenum really is one of life's few true essentials.
Meera Senthilingham
So time to give some much-owed respect, it seems, to the element molybdenum. That was science broadcaster Quentin Cooper with the widely applied chemistry of molybdenum. Now, next week, blink and you may miss it.
Brian Clegg
If elements were insects, darmstadtium would be the mayfly of the chemical world. It exists for the most fleeting time before it transforms to something else. Darmstadium is never going to have a practical use - but its sheer brevity of existence gives it a wistful fascination.
Meera Senthilingham
If you are looking for more details, kindly visit Niobium Bar.
And to find out what does happen in darmstadtium's brief existence on earth, in next week's Chemistry in its element. Until then, I'm Meera Senthilingham and thank you for listening.
(Promo)
Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists.com . There's more information and other episodes of Chemistry in its element on our website at chemistryworld.org/elements
(End promo)
This is a fact sheet intended for health professionals. For a general overview, see our consumer fact sheet.
Molybdenum is an essential trace element that is naturally present in many foods and is also available as a dietary supplement. Molybdenum is a structural constituent of molybdopterin, a cofactor synthesized by the body and required for the function of four enzymes: sulfite oxidase, xanthine oxidase, aldehyde oxidase, and mitochondrial amidoxime reducing component (mARC). These enzymes metabolize sulfur-containing amino acids and heterocyclic compounds including purines and pyrimidines [1,2]. Xanthine oxidase, aldehyde oxidase, and mARC are also involved in metabolizing drugs and toxins [3-6].
Molybdenum appears to be absorbed via a passive nonmediated process, though where absorption occurs in the intestinal tract is not known [1]. Adults absorb 40% to 100% of dietary molybdenum [2,7-10]. Infants absorb almost all of the molybdenum in breast milk or formula [11,12].
The kidneys are the main regulators of molybdenum levels in the body and are responsible for its excretion [1,2]. Molybdenum, in the form of molybdopterin, is stored in the liver, kidney, adrenal glands, and bone [2,7,13].
Because molybdenum deficiency is rare [14], molybdenum status is not assessed in clinical settings. According to a small study of 30 healthy men and women, serum levels of molybdenum range from 0.28 ng/mL to 1.17 ng/mL, and their average is 0.58 ng/mL [15]. In another small study of four healthy young men, plasma levels of molybdenum reached 6.22 ng/mL with a molybdenum intake of 1,490 mcg per day for 24 days [10]. The average concentration of urinary molybdenum is 69 ng/mL, but urinary molybdenum does not reflect molybdenum status [1].
Intake recommendations for molybdenum and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the National Academies of Sciences, Engineering, and Medicine [1]. DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and sex, include the following:
The basis for the EAR for molybdenum consists of two carefully controlled balance studies in a total of eight young men. The EAR for children and adolescents is extrapolated from adult values. Table 1 lists the current RDAs for molybdenum [1].
Table 1: Recommended Dietary Allowances (RDAs) for Molybdenum [1] Age Male Female Pregnancy Lactation Birth to 6 months 2 mcg* 2 mcg* 7–12 months 3 mcg* 3 mcg* 1–3 years 17 mcg 17 mcg 4–8 years 22 mcg 22 mcg 9–13 years 34 mcg 34 mcg 14–18 years 43 mcg 43 mcg 50 mcg 50 mcg 19+ years 45 mcg 45 mcg 50 mcg 50 mcg *AI, based on mean molybdenum intakes of infants fed primarily human milk.*AI, based on mean molybdenum intakes of infants fed primarily human milk.
Legumes are the richest sources of molybdenum [16]. Other foods high in molybdenum include whole grains, nuts, and beef liver [1,14,17,18].
The top sources of molybdenum in U.S. diets are legumes, cereal grains, leafy vegetables, beef liver, and milk [17]. Milk and cheese products are the main sources of molybdenum for teens and children [19].
The amount of molybdenum in food depends on the amount of molybdenum in the soil and in the water used for irrigation [1,2]. Drinking water generally contains only small amounts of molybdenum [17]. However, according to 2017 data from the U.S. Environmental Protection Agency, 0.8% of drinking water samples had molybdenum levels above 40 mcg/L [20]. The U.S. Department of Agriculture’s (USDA’s) FoodData Central [21] does not list the molybdenum content of foods or provide lists of foods containing molybdenum. Therefore, the amount of information on molybdenum levels in foods is quite limited.
Table 2: Molybdenum Content of Selected Foods [19] Food Micrograms*DV = Daily Value. The U.S. Food and Drug Administration (FDA) developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet. The DV for molybdenum is 45 mcg for adults and children age 4 years and older [22]. FDA does not require food labels to list molybdenum content unless molybdenum has been added to the food. Foods providing 20% or more of the DV are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet.
Molybdenum is available in dietary supplements containing molybdenum only, in combination with other minerals, and in multivitamin/mineral products. Amounts range from about 50 mcg to 500 mcg. Forms of molybdenum in dietary supplements include molybdenum chloride, sodium molybdate, molybdenum glycinate, and molybdenum amino acid chelate [23]. No studies have compared the relative bioavailability of molybdenum from these different forms.
Most Americans appear to consume adequate amounts of molybdenum. Although national surveys no longer collect data about molybdenum intake, FDA’s 1984 Total Diet Study estimated that average daily molybdenum intakes from foods were 109 mcg in men and 76 mcg in women [24]. According to the 1988–1994 National Health and Nutrition Examination Survey, molybdenum intakes from dietary supplements averaged 23 mcg/day for men and 24 mcg/day for women [25]. Intakes of molybdenum from drinking water collected from the 100 largest cities in the United States are estimated to be about 3 mcg/day based on intakes of 2 liters of water per day [26].
Molybdenum deficiency has not been reported, except in people with a genetic mutation that prevents the synthesis of molybdopterin and therefore of sulfite oxidase [14]. In this rare metabolic disorder, known as molybdenum cofactor deficiency, mutations in one of several genes prevent the biosynthesis of molybdopterin. The absence of molybdopterin impairs the function of enzymes that metabolize sulfite, leading to encephalopathy and seizures [1,14,27-29]; the neurological damage is severe and usually leads to death within days after birth [18,30].
A single reported incident of acquired molybdenum deficiency occurred in 1981 in a patient receiving total parenteral nutrition that was devoid of molybdenum. The patient developed tachycardia, tachypnea, headache, night blindness, and coma. These effects resolved with molybdenum administration [1,31].
No known groups of people are likely to have inadequate molybdenum intakes.
Molybdenum is not a standard treatment for any disease or disorder.
Acute molybdenum toxicity is rare, but it can occur with industrial mining and metalworking exposure. In healthy people, consumption of a diet high in molybdenum usually does not pose a health risk because the molybdenum is rapidly excreted in urine [1,14,18]. One study assessed the effect of high dietary intakes of molybdenum (10–15 mg/day) in an area of Armenia where the soil contains very high levels of molybdenum. The affected individuals experienced achy joints, gout-like symptoms, and abnormally high blood levels of uric acid [14].
Given the absence of human studies, the FNB established ULs for molybdenum for healthy individuals based on levels associated with impaired reproduction and fetal development in rats and mice [1].
Table 3: Tolerable Upper Intake Levels (ULs) for Molybdenum [1] Age Male Female Pregnancy Lactation Birth to 6 months None established* None established* 7–12 months None established* None established* 1–3 years 300 mcg 300 mcg 4–8 years 600 mcg 600 mcg 9–13 years 1,100 mcg 1,100 mcg 14–18 years 1,700 mcg 1,700 mcg 1,700 mcg 1,700 mcg 19+ years 2,000 mcg 2,000 mcg 2,000 mcg 2,000 mcg* Breast milk, formula, and food should be the only sources of molybdenum for infants.
Molybdenum has no known, clinically relevant, interactions with medications.
The federal government's 2020–2025 Dietary Guidelines for Americans notes that "Because foods provide an array of nutrients and other components that have benefits for health, nutritional needs should be met primarily through foods. ... In some cases, fortified foods and dietary supplements are useful when it is not possible otherwise to meet needs for one or more nutrients (e.g., during specific life stages such as pregnancy)."
For more information about building a healthy dietary pattern, refer to the Dietary Guidelines for Americans and the USDA's MyPlate.
The Dietary Guidelines for Americans describes a healthy dietary pattern as one that
This fact sheet by the National Institutes of Health (NIH) Office of Dietary Supplements (ODS) provides information that should not take the place of medical advice. We encourage you to talk to your health care providers (doctor, registered dietitian, pharmacist, etc.) about your interest in, questions about, or use of dietary supplements and what may be best for your overall health. Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice.
For more information, please visit Sintered Tungsten Rod.