Although perhaps not as well known as other minerals that we profile on our website, molybdenum is a key mineral nutrient found in a variety of WHFoods and known to play important roles in many different body systems.
Our understanding of molybdenum and human health did not begin with research on humans, but on soil, water, and microorganisms. Molybdenum has long been known to play a central role in soil chemistry, and in ocean chemistry as well. Some of the most fundamental components in soil and water chemistry—including basic interactions involving carbon, nitrogen, and sulfur—are significantly impacted by molybdenum and its role in chemical events. Not surprisingly, the molybdenum content of our food is significantly dependent on the soil in which foods are grown and the water supplied during the raising of the plants (or animals).
Like all nutrients, molybdenum needs to be consumed in amounts that fall within a healthy range, and it can be problematic to consume either too much or too little. We have research studies on both ends of this spectrum. On the one hand, there are studies showing healthy intake of molybdenum from molybdenum-rich soils and groundwater to be associated with increased longevity. (Studies involving rice intake in Zhongxiang, China are good examples of research because the growing circumstances for the rice involved molybdenum-rich soil and water.) At the same time, we have studies that show increased toxicity risk when industries release excessive amounts of molybdenum into the environment. (The manufacturing of light bulbs that require tungsten filaments and coils is a good example of an activity that can create potentially toxic levels of molybdenum in the surrounding air, water, and soil.) As a general rule, the general types of food that we eat in the U.S. and the many different environments in which these foods are grown tend to provide us with average amounts of molybdenum above the minimal requirement range yet well below an excessive level.
Unfortunately, scientists know more about the role of molybdenum in the environment and in non-human organisms than they do about the role of molybdenum in human health. Still, this mineral has been shown to be required for the activity of at least seven enzymes in our body, and numerous body systems rely on these enzymes for support. The information below is based on our understanding of these molybdenum-requiring enzymes and their rule in everyday health.
Sulfur is an element of surprising importance in our health. It's a unique part of the protein in our food because most foods contain at least small amounts of sulfur amino acids, including taurine, methionine, and cysteine. Sulfur is critical in our ability to detoxify unwanted contaminants, and many contaminants in our food cannot be eliminated from our body without the help of sulfur. This element is also essential in our body's antioxidant protection, and many of our most critical antioxidant molecules—including glutathione—are sulfur-containing. Sulfur also plays a unique role in the structure of our connective tissue, through its incorporation into molecules like glucosamine sulfate and chondroiton sulfate. So as you can see, this mineral is truly "whole body" in its health support role.
The same conclusion could be made about molybdenum as well, based on its required role in the activity of an enzyme called sulfite oxidase (SO). The role of SO is to take one form of sulfur (sulfite) and convert it into another form (sulfate). While this step sounds relatively simple, it is actually critical for keeping sulfur moving around in our body as intended and allowing all of the activities described in the paragraph above to take place. In other words, we suspect a role for molybdenum in support of liver detoxification, antioxidant support, connect tissue development, and other aspects of our health due to the widespread important of sulfur balance throughout our body.
While SO exits in many different organ systems in our body, two especially important places are our liver and brain. In the liver, SO is known to play a key role in support of detoxification. Our liver cells cannot do their job as detoxifiers if there is too much build-up of sulfite and not enough availability of sulfate, and SO helps prevent that problematic situation from occurring. (Within this context of detoxification, it is also important to note that molybdenum is a cofactor for the enzyme aldehyde oxidase, which is critical during the first phase of liver cell detoxification, called phase I.)
In the brain, we know that babies born with disruptions in molybdenum metabolism can have SO disruptions as well and can experience severe brain- and nervous system-related problems for this reason. The details here can get confusing, but they center on the role of a molecule called molybdenum cofactor, or Moco. Moco is the compound formed when molybdenum is combined with a molecule called pyranopterin. This molybdenum-containing compound turns out to be the form in which molybdenum helps to activate SO. While it is rare for babies to be born without the ability to make Moco, when this situation does occur, it can result in dramatic problems.
There are no small-scale or large-scale studies on humans to show whether dietary deficiency of molydenum can cause problems in detoxification, antioxidant protection, or brain and nervous system function. At the very least, we would suspect that over long periods of time (measured in years), very low intake of molybdenum would put people at risk of problems involving imbalanced sulfur metabolism. But there are simply no studies in this area. In addition, most of the studies that we have seen estimating dietary intake of molybdenum fall into the range of 80-300 micrograms per day, and with the Dietary Reference Intake (DRI) recommendation of 45 micrograms for adults 19 and older, you can see how evidence about dietary deficiency of this mineral might be difficult to obtain.
In addition to its role in SO activity, molybdenum is also a cofactor for an enzyme called xanthine oxidase (XO). XO is responsible for taking two molecules (called hypoxanthine and xanthine) and helping convert them into uric acid (UA). One context in which you might have heard about XO and UA is the medical condition often referred to as "gout," in which crystals of UA can build up in the joints and case pain. Medications used to help treat this condition often work by blocking the activity of XO. While it is true that too much uric acid can be a bad thing in some individuals, it is equally true that healthy amounts of uric acid are also quite important for all of us. We know, for example, that UA plays a primary role in the total antioxidant capacity of our bloodstream—as important, for example, as vitamins E and C. We also know that UA can play a direct antioxidant role in other part of our body. What we don't know is how these antioxidant functions of UA are related either to diet or to risk of disease. The lack of research in this area makes it impossible for us to say whether dietary deficiency of molybdenum might result in problems with UA formation that are accompanied by increased disease risk. But our knowledge of basic science in this area tells us that molybdenum is likely to contribute to our antioxidant protection by maintaining proper function of XO and balanced production of UA.
Because of its known role as a cofactor for the enzyme aldehyde dehydrogenase (ADH), molybdenum is likely to play an important role in nervous system metabolism, and particularly metabolism of the nervous system messaging molecules (neurotransmitters) epinephrine, norepinephrine, serotonin, and melatonin. ADH enzyme activity is critical for the breakdown of the neurotransmitters listed above, and the rate of breakdown of these molecules is closely related to their rate of synthesis and availability for nervous system function.
Molybdenum is also known to be required in formation of unique proteins called amidoxime reducing component proteins, or mARC. These proteins play important roles in mitochondrial function. (Mitochondria are energy-producing components in cells that participate in oxygen-based energy production, also called aerobic energy production.) However, this area of study is in its infancy and we are quite a way from practical conclusions involving dietary molybdenum intake and this aspect of mitochondrial function.
About 20% of our WHFoods qualify as ranked sources of molybdenum. While this number is relatively small compared to many of the nutrients that we profile on our website, we suspect that the actual number of molybdenum-containing foods is much higher. However, food databases like the U.S. Department of Agriculture's National Nutrient Database for Standard Reference do not even include molybdenum in their routinely available data. This lack of basic information on the molybdenum content of food is an obstacle in our evaluation of molybdenum-rich foods.
Based on information that we do have, our best WHFoods sources of molybdenum tend to fall into the Beans & Legumes group. Our top eight sources of molybdenum all belong to this group, including lentils, dried peas, and the following beans: limas, kidneys, black, soy, pintos, and garbanzos. All eight rank as excellent sources of this mineral. Also included as excellent sources are oats, tomatoes, romaine lettuce, cucumber, and celery. Our very good sources of molybdenum include a second grain (barley) as well as additional vegetables (carrots, bell peppers, and fennel). From our Eggs & Dairy group, eggs and yogurt also qualify as very good sources. It's worth noting here that for some people in the U.S., about 20% of daily molybdenum intake comes from this Eggs & Dairy group, and in some studies of teenagers, this percentage is even higher and can approach about 40%.
Foods from additional food groups—including sesame seeds, walnuts, and almonds from our Nuts & Seeds group, and cod from our Fish group—get added to the molybdenum-rich list when "good" sources of this nutrient are included.
In its analysis of U.S. molybdenum intake, the National Academy of Sciences (NAS) has estimated that adult men in the U.S. average 106 micrograms of dietary molybdenum per day, and adult women average 76 micrograms. Both of these intake levels are well above the adult Dietary Reference Intake (DRI) level for this mineral, which is 45 micrograms. We would also add here that a single serving of any of our top eight molybdenum-rich foods from the Beans & Legumes group provides well over this DRI level.
|World's Healthiest Foods ranked as quality sources of|
|Dried Peas||1 cup||231.3||147.00||327||25.4||excellent|
|Lima Beans||1 cup||216.2||141.00||313||26.1||excellent|
|Kidney Beans||1 cup||224.8||132.75||295||23.6||excellent|
|Black Beans||1 cup||227.0||129.00||287||22.7||excellent|
|Pinto Beans||1 cup||244.5||128.25||285||21.0||excellent|
|Garbanzo Beans||1 cup||269.0||123.00||273||18.3||excellent|
|Romaine Lettuce||2 cups||16.0||5.64||13||14.1||excellent|
|Barley||0.33 cup||217.1||26.99||60||5.0||very good|
|Eggs||1 each||77.5||8.50||19||4.4||very good|
|Carrots||1 cup||50.0||6.10||14||4.9||very good|
|Bell Peppers||1 cup||28.5||4.60||10||6.5||very good|
|Fennel||1 cup||27.0||4.35||10||6.5||very good|
|Sesame Seeds||0.25 cup||206.3||10.62||24||2.1||good|
|Green Peas||1 cup||115.7||6.89||15||2.4||good|
Density>=7.6 AND DRI/DV>=10%
Density>=3.4 AND DRI/DV>=5%
Density>=1.5 AND DRI/DV>=2.5%
Like most minerals, we haven't seen any evidence for degradation of molybdenum content in foods when they are stored in keeping with our WHFoods recommendations. We do not, therefore, recommend any specific storage method to enhance mineral nutrition for molybdenum. Instead, we simply encourage you to follow our food-specific storage methods described in each of our individual food profiles. We have not seen good quality research on the loss of molybdenum during cooking. However, since many of our top sources for this mineral involve foods from the Beans & Legumes group, and since our Beans & Legumes rankings for molybdenum are all based on cooked versions of these foods, we have a high level of confidence in their nutrient richness for this mineral, even in cooked form. We have seen some Internet content warning about high levels of molybdenum exposure from stainless steel cookware. While we have seen studies measuring transfer of other minerals (for example, chromium) from stainless steel pots and pans into food, we have not seen studies analyzing molybdenum. Nor have we seen studies showing toxicity from general mineral transfer from cookware into food.
While stainless steel does contain molybdenum, different types of stainless steel can contain widely varying amounts. In general, we like the use of stainless steel in cooking. Like all cookware, we believe that it is important to keep stainless steel in good condition. In this case, "good condition" means maintain smooth food-contact surfaces that are not scratched or abraded. If the inner surfaces of stainless steels pots and pans are no longer smooth and intact, your best option if you want to minimize transfer of stainless steel metals into food is to replace the cookware.
Could it be a good thing for molybdenum to pass from your stainless steel cookware into your food? Unfortunately, we cannot answer this question since we haven't seen studies showing the potential amount of molybdenum that could get transferred. However, it's worth noting that in some situations, migration of minerals from cookware into food can be considered helpful. For example, for a person deficient in iron, transfer of iron from cast-iron cookware into food can help increase iron intake. Once again, we would emphasize the lack of research in this area with respect to stainless steel cookware and molybdenum. In the absence of this research, we continue to support the use of stainless steel in your kitchen, along with the recommendation that you keep your cooking surfaces in good condition.
The risk of dietary deficiency of molybdenum in the United States appears to be quite low. As mentioned earlier, the National Academy of Sciences estimated 106 micrograms of daily molybdenum intake for adult men and 76 micrograms for adult women— amounts well above the DRI. We have also seen an earlier 1980 study showing adult intake of about 120 to 240 micrograms of molybdenum per day. All of these numbers fall into the broader range of 80-300 micrograms of dietary molybdenum that we've seen in estimates from other countries.
We are also not aware of reports of symptoms related to dietary deficiency of molybdenum in healthy adults. Typically, reports of deficiency symptoms are common if there is widespread deficiency of a nutrient.
That said, we also see that it is quite possible to eat a diet that does not contain the types of foods that are richest in this mineral. We do recommend including legumes and molybdenum-rich vegetables (like tomatoes, romaine lettuce, cucumbers, and tomatoes) on a routine basis to ensure healthy molybdenum intake. We would single out the Beans & Legumes group as especially helpful for good molybdenum intake. Ideally, foods from this group would be included in your meal plan at least several days each week to help ensure good molybdenum intake. If you never eat foods from this group, you could still reach your molybdenum goals, but it could be much more challenging for you to do so. A clear exception to this statement would be the following daily food list: hearty intake of our most molybdenum-rich vegetables: tomatoes, romaine lettuce, cucumbers, and celery (providing you with a total of about 25 micrograms of molybdenum), coupled with a serving of yogurt and a serving of walnuts (providing another 20 micrograms). This combination would put you right at the recommended daily amount of 45 micrograms.
With the exception of a single published study on a hospitalized patient in poor physical condition, we haven't seen research documentation on specific events leading to molybdenum deficiency. If common circumstances are able to increase molybdenum deficiency risk, we have yet to see science-based evidence in this regard.
We sometimes see sources that suggest that too much molybdenum could deplete copper levels. To our knowledge, however, this is only true in ruminant animals like cattle or sheep. We have not seen any credible reports of humans ingesting enough dietary molybdenum to cause depletion of copper or any other nutrient. In keeping with this observation, the National Academy of Sciences did not consider this copper interaction to be relevant for humans in their determination of a Tolerable Upper Intake Limit (UL) for molybdenum.
All of the enzymes that use molybdenum require iron as they are being assembled. Additionally, the sulfite oxidase enzymes use iron in the form of heme (the same iron-containing protein found in red blood cells) along with molybdenum in their detoxification activity. As such, you'll want to make sure your iron nourishment is appropriate to ensure proper molybdenum utilization.
Exposure to the environmental toxin tungsten could potentially interfere with molybdenum metabolism. This is because tungsten can replace molybdenum in its role as an enzyme cofactor. However, tungsten only occurs in the human diet in tiny amounts, and exposure to tungsten is most likely to occur in people exposed on the job (for example, in a factory manufacturing tungsten filaments and coils for light bulbs).
We are not aware of research showing toxic levels of molybdenum in foods, except in situations involving environmental contamination as mentioned above. As such, we believe that there is little cause for concern about excessive dietary intake of this nutrient in the vast majority of circumstances.
At extreme amounts in animal studies, molybdenum can cause stunted growth, kidney damage, bone loss, anemia, and infertility. None of these potential problems has been observed in humans, however, and we assume this lack of evidence is largely due to the virtual impossibility of consuming such high levels of molybdenum from food, except perhaps in circumstances involving industrial contamination of the environment. (As mentioned earlier, if too much molybdenum gets released from a manufacturing facility and plants and animals in the immediate area get exposed to excessive molybdenum, and then humans living in the area consume those plants and animals for food, it is definitely possible for this scenario to result in excessive dietary intake of molybdenum.) However, this type of dietary exposure is definitely the exception and not the rule.
As mentioned earlier, the National Academy of Sciences (NAS) has established a Tolerable Upper Intake Level (UL) of 2 milligrams, or mg (the same as 2,000 micrograms, or mcg) for adult men and women 19 years and older. For younger persons, the ULs are as follows.
Two other categories of ULs are as follows.
In 2001, the National Academy of Sciences established Dietary Reference Intakes (DRIs) for molybdenum. These DRIs are summarized in the chart below. Note that the DRI recommendation for infants under one year of age comes in the form of an Adequate Intake (AI) level, and all other recommendations come in the form of a Recommended Dietary Intake (RDA).
The DRI report for molybdenum also established a Tolerable Upper Intake Levels (ULs) as follows.
The Daily Value (DV) for molybdenum is 75 micrograms (mcg) per day. This is the standard that you will see on food and supplement labels.
At WHFoods, we have adopted the adult DRI for molybdenum of 45 micrograms (mcg) as our recommended daily intake level.