Trace Minerals
Mineral Review
Minerals are inorganic elements that are essential to human nutrition. Minerals are important for your body to stay healthy. Your body uses minerals for many different jobs, and those jobs include building bones, making hormones, and regulating your heartbeat.
There are two kinds of minerals: major minerals (also called macrominerals) and trace minerals (or microminerals). The best way for you to get the minerals your body needs is by eating a wide variety of foods; however, there may be some cases in which your doctor may recommend that you take a mineral supplement. Eating foods that are high in minerals does not mean that your body will actually absorb the minerals during digestion. As a matter of fact, the amount of a particular mineral that is ultimately available for your body to use depends on the amount of that mineral that your body can absorb and retain. This is known as bioavailability.
Bioavailability is affected by many different factors. For example, if your body already has enough of a certain mineral, and you consume foods that are high in that mineral, your body will not absorb more of that mineral than it needs. On the other hand, if your body is deficient in that mineral, it will absorb more of that mineral from the foods you eat (that contain that mineral) than it really needs. Cooking certain foods, such as beans, increases the bioavailability of minerals in them. Some nutrients interact to change the bioavailability of other nutrients. Specifically, vitamin C increases the bioavailability of iron by increasing absorption, and vitamin D increases the absorption of calcium, magnesium, and phosphorus. On the other hand, there are several factors that reduce the bioavailability of minerals. Supplementation of single minerals affects the absorption of competing minerals. Also, certain properties of some foods reduce bioavailability.
Trace Minerals
Unlike major minerals, your body needs just small amounts of trace minerals, which are also called microminerals. Altogether, you have less than 5 grams of trace minerals in your entire body, and your dietary need for each of these minerals is less than 20 milligrams per day. Despite the fact that these minerals have low dietary requirements, trace minerals are just as important and necessary for health as the other nutrients are. Some of the essential roles of trace minerals include helping with hormone function, maintaining the health of your red blood cells, and protecting your bones and teeth. The nine primary trace minerals are chromium, copper, fluoride, iodine, iron, manganese, molybdenum, selenium, and zinc.
CHROMIUM
Chromium (Cr) is a trace mineral that is important for the metabolism of glucose. Its main function is to increase the effectiveness of insulin in your cells. Chromium may also reduce your blood sugar levels, and that results in a reduced risk of developing prediabetes. It has also been shown to reduce the risk of other health problems (such as cardiovascular disease, among others) as well as to improve them.
Many foods contain chromium, but the amounts found in those foods varies and is influenced by the amount of chromium that is in the soil where the foods grow. Whole grains are rich sources of chromium; refined grains also have chromium, but they have chromium in far smaller amounts than whole grains. Meat (including poultry and fish) and some fruits and vegetables also provide chromium in the diet.
The RDA is 24 mcg/day for females ages fourteen to eighteen and 35 mcg/day for males age fourteen and older.
There is no UL for chromium.
COPPER
Copper (Cu) is an essential trace mineral that is present in all tissues in your body. Copper works with iron to help your body form red blood cells. Copper helps keep things healthy, including blood vessels, nerves, your immune system, and bones. Copper also aids in iron absorption. Additionally, copper helps your body produce energy, helps maintain the coloring in your skin (pigmentation), helps your blood clot, and is important for helping your immune system function properly.
Normally, people get enough copper from what they eat during the day (in meals and snacks). However, if you do not get enough copper, you may get anemia (low levels of iron in your blood) and/or osteoporosis (weakening of your bones). On the other hand, if you get too much copper, it is poisonous.
Some of the best sources of copper are oysters and other shellfish. In addition, beans, nuts, whole grains, potatoes, and organ meats (such as kidneys and liver) provide copper. Other foods that contain some copper are dark leafy greens, dried fruits (such as prunes), cocoa, black pepper, and yeast.
The RDA is 890 mcg/day for teens.
The UL is 8,000 mcg/day for teens ages fourteen to eighteen.
FLUORIDE
Fluoride (F) is a safe ion form of fluorine (a poisonous gas). Fluoride is not considered an essential nutrient because the body does not need it to grow and develop normally. However, fluoride does play a very important role in helping teeth develop and become strong so they are better able to resist decay. Fluoride is found naturally in plants and animals, and many cities add it to water supplies. (You will not have fluoride added to your water if you have well water.) Almost all the fluoride you consume in your diet is absorbed in your small intestine, and it is taken up and used by your bones and developing teeth. The best-known function of fluoride is that it helps maintain healthy teeth. It does this by helping harden the outer layer of your teeth (enamel) and helping make your teeth resistant to damage.
Getting too little fluoride increases your risk of developing dental caries (cavities) and other disorders of the teeth. On the other hand, if you get too much fluoride, you can get a condition called fluorosis. Fluorosis causes the teeth to become pitted/mottled and develop white patches or stains on their surfaces; fluorosis also increases the risk of dental caries. However, fluorosis is only a risk for children whose teeth are still developing (this is generally children who are eight years old and younger). On the other hand, adults are at risk of developing fluorosis of the bones if they have too much fluoride in their diets. Because of this risk, the UL for fluoride is set at 10 mg/day for anyone age nine and older.
Foods are not good sources of fluoride. The best sources of fluoride are fluoridated water and any liquids that are made with fluoridated water (coffee, tea, juices from concentrate, soup, etc.). Decaffeinated tea is also a good source of fluoride even when it is not made with fluoridated water. This is because when tea is decaffeinating, the process adds minerals (including fluoride) to the water used; decaffeinated tea has about twice the amount of fluoride as tea that has caffeine in it (and has not been decaffeinated). Some bottled waters also contain fluoride, but you will need to check the bottles to see if they have fluoride, and how much fluoride they have in them if they do.
The RDA is 3 mg/day for females age fourteen and older and 4 mg/day for males age fourteen and older.
The UL, as mentioned, is 10 mg/day for individuals age nine and older.
IODINE
Iodine (I) is an essential mineral that is important for the proper functioning of your thyroid gland. Your thyroid gland affects most of the cells in your body that help regulate your metabolic rate, reproduction, and nerve, muscle, and heart function. The thyroid also produces hormones that control your body's energy production, metabolism, normal growth of bones, and brain development. Iodine deficiency can cause brain damage in a developing baby and enlarged thyroid glands (called goiter) in children and adults. Beginning in the 1920s, iodine was added to salt, and this practice continues today. Because iodine is added to salt, iodine deficiency is virtually nonexistent in the developed world. On the other hand, consuming too much iodine can cause problems with how your thyroid functions.
Iodized salt is table salt that has iodine added to it. Iodized salt is the main food source of iodine. Seafood (especially cod, sea bass, haddock, and perch) is also naturally rich in iodine. The most common vegetable seafood that is a rich source of iodine is kelp. Dairy products also contain some iodine. Other good sources of iodine are plants that were grown in iodine-rich soil.
The RDA is 150 mcg/day for individuals age fourteen and older.
The UL is 900 mcg/day for teens ages fourteen to eighteen.
IRON
Iron (Fe) is the most abundant mineral on Earth, and it is the most abundant trace element in the human body. Iron is a mineral your body needs in order to grow, develop, and support many functions. For example, iron is part of your hemoglobin, which is a protein that carries oxygen from your lungs throughout your body. It helps your muscles store and use oxygen. Your body also needs iron to make some of your hormones and connective tissues. Iron is also part of many other proteins and enzymes in your body.
Your body needs the right amount of iron. If you have too little iron, you may develop an anemia called iron deficiency anemia. Some of the causes of low iron levels are loss of blood (from wounds or menstruation), poor diet, or an inability of your body to absorb enough iron from foods. People who are at greater risk of having too little iron are young children and women who are pregnant or have heavy periods. On the other hand, too much iron can damage your body. If you take in too much iron from supplements, it can cause iron poisoning.
Iron is found naturally in many foods, and it is added to some fortified food products. You can usually get the recommended amount of iron by eating a variety of foods. Those foods include lean meat, poultry, seafood, iron-fortified breakfast cereals and/or bread, spinach, lentils, white beans, kidney beans, peas, nuts, and some dried fruits (such as raisins). Your body absorbs iron from plant sources better when you eat those foods with meat (including poultry and seafood) and foods that contain vitamin C (like citrus fruits and tomatoes).
The RDA is 15 mg/day for female teens and 11 mg/day for male teens.
The UL is 45 mg/day for individuals age fourteen and older.
MANGANESE
Manganese (Mn) is a trace mineral that is either part of the enzymes in your body or activates many of the enzymes in your body. Much of the manganese in your body is found in your bones and the "accessory organs" of your digestive tract (such as your liver and pancreas). This mineral helps you metabolize carbohydrates, fats, and amino acids, and it also helps form your bones and cartilage.
Manganese is found in plant foods. Some foods that are excellent sources of manganese are whole grains (whole wheat, oats, etc.), nuts, legumes, vegetables, and fruits (such as pineapples, strawberries, and bananas). Another good source of manganese is ground cinnamon.
The RDA is 1.6 mg/day for females ages fourteen to eighteen and 2.2 mg/day for males ages fourteen to eighteen.
The UL is 9 mg/day for teens ages fourteen to eighteen.
MOLYBDENUM
Molybdenum (Mo) is a trace mineral that is also an enzyme that helps break down certain amino acids and other compounds in your body. Deficiencies of this nutrient are generally not found in people who are healthy. Individuals who do not get enough molybdenum, especially if and when they are fed intravenously for an extended period of time, may develop a rapid heartbeat, headaches, and night blindness.
Legumes are an excellent source of molybdenum. Other food sources of this mineral are dairy products, grains, nuts, and leafy green vegetables.
The RDA is 43 mcg/day for teens.
The UL is 1,700 mcg/day for teens ages fourteen to eighteen.
SELENIUM
Selenium (Se) is a trace mineral that is unique in that almost all the selenium you consume is absorbed by your body. Unlike iron and zinc, the absorption of selenium is not controlled by your small intestine. Once it is absorbed, selenium is stored in different tissues in your body (such as your bones, muscles, liver, and kidneys). If you consume too much, the excess will be excreted by your kidneys in urine. Selenium is important for regulating the hormones in your thyroid gland, and it has been linked to lower risks of developing cancers of the lungs, colon, and prostate because of the antioxidants it has.
While selenium deficiency is rare in the United States, when a deficiency occurs, it can damage your heart. This is usually only a problem among children who live in rural areas that have little selenium in the soil. Selenium deficiency may cause problems with the hormones that regulate your thyroid gland. Too much selenium may cause your hair and nails to be brittle, discomfort in your stomach and intestinal tract, skin rash, breath that smells like garlic, fatigue, and damage to your nervous system.
The RDA is 55 mcg/day for individuals age fourteen and older.
The UL is 400 mcg/day for individuals age fourteen and older.
ZINC
Zinc (Zn) is a trace mineral found in small amounts in almost every cell of your body; most of it is found in your bones and muscles. The absorption of zinc is controlled by your small intestine. Zinc contributes to a healthy immune system, works as an antioxidant, and helps keep your cell membranes stable. It also helps reduce inflammation of your wounds while helping your wounds heal properly.
Too much zinc can cause stomach pain, nausea, vomiting, and diarrhea. If you consume too much zinc, it can suppress your immune system and lower your "good" cholesterol levels. If you take in too much iron, it can inhibit the absorption of zinc, and that can result in a zinc deficiency. A zinc deficiency can cause skin rash, hair loss, impaired taste of foods, loss of appetite, diarrhea, and delayed sexual maturation. One sign of a zinc deficiency in children is delayed or slow growth.
Animal proteins are excellent sources of zinc; some animal sources (such as beef, lamb, pork, and the dark meat of chicken) contain more zinc than other sources (such as fish and the light meat of chicken). Legumes, beans, nuts, whole grains, and yeast are some plant sources that contain good supplies of zinc. However, most fruits and vegetables are not adequate sources of zinc because the zinc that is in those plant proteins is not used in your body as efficiently as zinc from animal proteins. Because of that, low-protein diets and vegetarian diets are often low in zinc. However, zinc is in most multivitamin and mineral supplements. Zinc is also present in some of the over-the-counter medicines you might buy and use; some examples are cold lozenges, nasal sprays, and nasal gels.
The RDA is 9 mg/day for females ages fourteen to eighteen and 11 mg/day for males age fourteen and older.
The UL is 34 mg/day for teens ages fourteen to eighteen
Other Trace Elements
There are a few other elements that exist in your body, but their role in the health and nutrition of humans has not yet been established. These elements include arsenic, boron, nickel, silicon, and vanadium.
ARSENIC
There are two kinds of arsenic: organic and inorganic. There are no known adverse effects caused to humans by consuming the organic form of arsenic in foods. However, the inorganic form of arsenic is poisonous to humans.
Food sources (which are organic sources) of arsenic include meat (including poultry and fish), dairy products, grains, and cereals.
BORON
There are no known adverse effects from consuming boron in foods by humans. However, some research indicates that people who consume high amounts of boron can have reproductive problems and problems with development. Most studies on boron have been conducted on animals. Because of the adverse effects of boron seen in animals, the UL for boron is 20 mg/day for adults, and that amount is more than ten times greater than the amount the average American consumes each day.
Food sources of boron include milk, peanut butter, pecans, legumes, potatoes, apples, and grape juice.
NICKEL
Nickel may be needed by certain enzymes in your body, but it is not considered an essential mineral for humans.
There is no known toxic level of nickel in humans who consume it as part of their normal diet. However, in rats, exposure to high levels of nickel salts can cause symptoms of toxicity (lethargy, irregular breathing, and below-average weight). Because of the effects, scientists have seen in rats, the UL for nickel salts has been set at 1 mg/day for adults.
Food sources of nickel include grains and grain products, nuts, legumes, vegetables, and chocolate.
SILICON
Based on scientific studies, silicon has been deemed important for bone formation in animals. There is no known risk of toxicity in animals from consuming too much silicon. Studies have not been conducted on humans, so information on human consumption of silicon is limited.
Food sources of silicon include grains and grain products and vegetables.
VANADIUM
Vanadium has insulin-like actions in animals, and a deficiency of vanadium increased the risk of miscarriage (spontaneous abortion) in the animals used in studies on this nutrient. There is no known risk of toxicity in humans from vanadium in foods. However, too much vanadium has been shown to cause kidney damage in animals. Because of the known toxicity in animals, the UL for vanadium has been set at 1.8 mg/day for adults.
Food sources of vanadium include mushrooms, parsley, black pepper, and shellfish.
This trace mineral is important for the regulation of blood glucose. - Chromium
This trace mineral is important for the proper functioning of your thyroid gland. - Iodine
This trace mineral helps protect your teeth from cavities and is often added to water. - Fluoride