Vanadium

Description

Named after the Scandinavian goddess of youth and beauty, vanadium is a trace element that has gained attention in recent years as a possible aid in controlling diabetes. While such macrominerals as calcium, magnesium , and potassium have become household names because they make up over 98% of the body's mineral content, certain trace minerals are also considered essential in very tiny amounts to maintain health and ensure proper functioning of the body. They usually act as coenzymes, working as a team with proteins to facilitate important chemical reactions. Even without taking vanadium supplements, people have about 20–25 micrograms (mcg) of the mineral in their bodies, which is derived from an average balanced diet. Despite the fact that vanadium has been studied for over 40 years, it is still not known for certain if the mineral is critical for optimal health. Whether taking extra amounts of vanadium is therapeutic or harmful is even more controversial. Like chromium , another trace mineral, vanadium has become the focus of study as a possible aid in lowering blood sugar levels in people with diabetes. Vanadium has also been touted as a potential treatment for osteoporosis . Some athletes and weight lifters take it to build muscle or improve performance.

Studies in animals suggest that vanadium may be necessary for the formation of bones, teeth, and cartilage. The mineral may also play a role in growth and reproduction as well as affect the processing of cholesterol and insulin in the body. In one animal study, goat kids whose mothers received a diet deficient in vanadium showed skeletal damage; they died within days of their birth. In studies of mice, vanadium has been shown to lower blood sugar and levels of low-density lipoprotein (LDL) cholesterol and triglyceride. It is not certain, however, that such study results as these confirm the nutritional importance of the mineral for human beings. The effects of a vanadium-free diet have not been studied in people. Even if vanadium supplements prove to be effective for certain purposes, such as helping to control diabetes, animal studies suggest that the high dosages of vanadium necessary to produce results may be harmful. High dosages are often necessary because vanadium is not well absorbed by the body. As of 2000, a significant amount of research is still required to determine if vanadium can in fact produce significant health benefits safely and effectively. The proper dosage of the mineral supplement has also yet to be determined.

General Use

Vanadium has been investigated most often as a possible aid in controlling diabetes. Studies in animals with type 1 (insulin-dependent) and type 2 (non-insulin-dependent) diabetes indicate that vanadium can help to improve blood sugar levels. Studies using human subjects have produced encouraging if preliminary results. Vanadium is used by some athletes and weight lifters to build muscle despite the fact that it does not appear to be effective for this purpose. Moreover, the potential usefulness of vanadium in treating osteoporosis is considered highly speculative. All of the human studies discussed below were conducted in small numbers of people for short periods of time and involved relatively high dosages of the mineral.

Diabetes

Several studies conducted in people suggest that vanadium may help to control blood sugar levels in diabetics. The mineral appears to work by mimicking the effects of insulin or by increasing the body's sensitivity to the hormone. This mechanism could allow diabetics to effectively control their blood sugar while using lower dosages of insulin medication. In a placebo-controlled study published in 1996 in the medical journal Metabolism, eight people with type 2 diabetes received vanadium for one month. Researchers found that vanadium was moderately successful in lowering blood sugar levels and had few side effects. Six of the eight patients taking vanadium during the study experienced gastrointestinal side effects during the first week of treatment, but these disappeared with continued use. In another small study of vanadium involving people with type 2 diabetes, published in the Journal of Clinical Investigation in 1995, researchers from the Albert Einstein College of Medicine reported that three weeks of treatment with the mineral improved the body's sensitivity to insulin. The effects of vanadium in lowering blood sugar levels persisted for up to two weeks after the drug was discontinued. A study published in the journal Diabetes in 1996, which involved seven people with type 2 diabetes as well as six nondiabetics, reported that vanadium improved insulin sensitivity in the diabetic subjects. Interestingly, the mineral did not improve sensitivity in the subjects who did not have the disease.

Sports medicine

The use of vanadium by body builders appears to stem from a misunderstanding of the mineral's effects. Because insulin is a hormone that plays a role in increasing muscle mass, some weight lifters have taken vanadium in high dosages because they believe it will act like insulin and make them stronger. The problem is that vanadium does not appear to mimic insulin or increase its efficiency in healthy people, only in diabetics. For people considering vanadium as an aid in strengthening muscles, the scientific evidence is not very convincing. In one double-blind, placebo-controlled study published in the International Journal of Sport Nutrition in 1996, high dosages of vanadium were given to a few dozen weight trainers for 12 weeks. The bench press and leg extension weight-training exercises were used to measure results. Researchers found that there was no difference in body composition between those who took vanadium and those in the placebo group. Vanadium appeared to slightly enhance performance during the leg extension aspect of the study, but this advantage can be explained by other factors and cannot be attributed to the mineral itself with any certainty.

Osteoporosis

It is important not to confuse vanadium with calcium . Calcium is considered an essential building block of bone, and calcium supplements are often an important part of a bone-strengthening program in women with osteoporosis. Studies in mice indicating that vanadium is also deposited in bone have led to suggestions that the mineral may be effective as a potential treatment for osteoporosis. It is known, however, that minerals can be added to bones without actually making them stronger. There is no evidence that taking vanadium supplements can increase bone density in humans.

Preparations

The estimated dosage of vanadium, which is available as an over-the-counter dietary supplement, generally ranges from 10–30 mcg a day. It is important to remember, however, that safe and effective dosages for the mineral have not yet been established. Some practitioners of complementary medicine, such as Dr. Robert Atkins, have recommended dosages as high as 25–50 mg (milligrams, not micrograms) daily for people with diabetes. The long-term health risks associated with taking dosages in this range are unknown.

Even without taking supplements, most adults get anywhere between 10–60 mcg of vanadium through a normal diet. Some authorities believe it is safer for people to avoid vanadium supplements altogether and increase their intake of foods known to contain the mineral. These include meat, seafood, whole grains, vegetable oil, canned fruit juices, soy products, and such vegetables as green beans, corn, carrots, and cabbage. Alcoholic beverages such as wine and beer also contain vanadium. Over-dosing on the vanadium contained in food is not considered a significant risk because the mineral is present only in very small amounts in plants and animals.

Precautions

It is important not to exceed the recommended intake of vanadium without medical supervision. Studies conducted in rats suggest that high dosages of vanadium can be harmful. This results from the fact that the mineral tends to build up in the body, reaching dangerously high levels when taken in excess. The reader should keep in mind that high dosages of vanadium have not yet been proven to have significant health benefits. The long-term health risks associated with taking vanadium supplements (in any dosage) are unknown.

Side effects

When taken in recommended dosages, vanadium has not been associated with any significant or bothersome side effects. At high dosages, vanadium has been known to cause stomach cramping and diarrhea as well as a green tongue.

Interactions

No drugs are known to interact adversely with vanadium. Smokers may absorb less of the mineral.

Resources

BOOKS

Atkins, Robert C. Dr. Atkins' Vita-Nutrient Solution. New York: Simon & Schuster, 1998.

Miller, Lucinda G., and Wallace J. Murray. Herbal Medicinals: A Clinician's Guide. New York: Pharmaceutical Products Press, 1998.

Sifton, David W. PDR Family Guide to Natural Medicines and Healing Therapies. New York: Three Rivers Press, 1999.

ORGANIZATIONS

Herb Research Foundation. 1007 Pearl Street, Suite 200. Boulder, CO 80302.

National Diabetes Information Clearinghouse. 1 Information Way. Bethesda, MD 20892-3560.

OTHER

Discovery Health. http://www.discoveryhealth.com.

National Institute of Diabetes and Digestive and Kidney Diseases. http://www.niddk.nih.gov.

Greg Annussek

Vanadium

melting point: 1,910 ±10°C
boiling point: 3,047°C
density: 6.11 g/cm³
most common ions: V²⁺, V³⁺, VO⁺, VO₂⁺

Vanadium is a soft silver metal in group 5B of the Periodic Table. It was discovered in Mexican lead ore by Andreas Manuel del Rio in 1801. Because of the red color of its salts, he named it erythronium (the Greek word erythro means "red"). Upon challenge by H. V. Colett-Desotils, del Rio withdrew his claim. In 1830 the element was rediscovered by Nils Selfstöm in iron ore. Since the element is found in compounds of many different colors, he named it "vanadium" after the Scandinavian goddess of beauty, Vanadis.

Vanadium is the nineteenth element in abundance (136 ppm) and the fifth most abundant transition element in Earth's crust. It is found in approximately sixty-five different minerals (such as roscoelite and vanadinite), phosphate rock, iron ores, and some crude oils as organic complexes. Since there are few concentrated deposits of vanadium compounds, it is obtained as a coproduct of refining. The element has two naturally occurring isotopes : ⁵⁰V (0.25%) and ⁵¹V (99.75%).

Although vanadium is an essential trace element , its exact role has not been determined. It is found in the blood of the ascidian seaworm. A related species has vanadium concentrations of up to 1.45 percent in its blood cells. The metal may play a role in the oxygen transport system.

Vanadium reacts with most nonmetals at high reaction temperatures (660°C; 1,220°F). The compounds of vanadium reflect the varied oxidation states possible for this element. Formal oxidation states of +5 to −1 have been found, with the +4 state being the most stable. The element has good corrosion resistance to alkali, acid, and salt water. For this reason it is used in rust resistant springs and high speed tools. Approximately 80 percent of the vanadium produced yearly is used as an additive to produce steel that has a resistance to wear. Vanadium oxide is used in ceramics and as a catalyst .

see also Corrosion; Steel.

Catherine H. Banks

Bibliography

Greenwood, N. N., and Earnshaw, A. (1997). Chemistry of the Elements, 2nd edition. Boston: Butterworth-Heinemann.

Lide, David R., ed. (2003). "Vanadium." In The CRC Handbook of Chemistry and Physics, 84th edition. Boca Raton, FL: CRC Press.

Internet Resources

"Vanadium." U.S. Geological Survey, Mineral Commodity Summaries. Available from <http://minerals.usgs.gov/minerals/pubs/commodity/vanadium/700303.pdf>.

vanadium , metallic chemical element; symbol V; at. no. 23; at. wt. 50.9415; m.p. about 1,890°C; b.p. 3,380°C; sp. gr. about 6 at 20°C; valence +2, +3, +4, or +5. Vanadium is a soft, ductile, silver-grey metal. It is the element above niobium in Group 5 of the periodic table . In its properties it resembles chromium. It is corrosion resistant at normal temperatures, but oxidizes above 660°C. It resists attack by hydrochloric and sulfuric acids, saltwater, or alkalies. Vanadium forms numerous compounds, including vanadates and complex organic compounds. Vanadium pentoxide, V ₂ O ₅ , is commercially important. Vanadium is not found uncombined in nature but occurs widely distributed in minerals. Important ores include carnotite, patronite, roscoelite, and vanadinite. In the United States vanadium ores are mined in Arizona, Colorado, and Utah; other sources are Peru and Africa. Vanadium is recovered from these ores largely as the pentoxide; the pentoxide is also recovered during phosphorus production in Idaho and from certain crude oils and petroleum ashes. The principal use of vanadium is in alloys, especially with steel . In tool and spring steels it is a powerful alloying agent; a small amount (less than 1%) adds strength, toughness, and heat resistance. It is usually added in the form of ferrovanadium, a vanadium-iron alloy. Vanadium compounds, especially the pentoxide, are used in the ceramics, glass, and dye industries, and are important as catalysts in the chemical industry. Although high-purity vanadium metal can be produced by chemical reduction of the trichloride, most commercial production of the metal is by calcium reduction of the pentoxide. Vanadium was discovered in 1801 by A. M. del Rio, who called it erythronium; however, it was mistaken for impure chromium. The element was rediscovered and named in 1830 by N. G. Sefström, a Swedish chemist. It was first isolated in 1867 by H. E. Roscoe.

vanadium (symbol V) Silver-white, metallic element, one of the transition elements. Discovered in 1801, the malleable and ductile metal is found in iron, lead, and uranium ores, and in coal and petroleum. It is used in steel alloys to add strength and heat resistance. Chemically, vanadium reacts with oxygen and other nonmetals at high temperature. Properties: at.no. 23; r.a.m. 50.9414; r.d. 6.1 at 18.7°C; m.p. 1890°C (3434°F); b.p. 3380°C (6116°F); most common isotope V⁵¹ (99.76%).

va·na·di·um / vəˈnādēəm/ • n. the chemical element of atomic number 23, a hard gray metal of the transition series, used to make alloy steels. (Symbol: V)

vanadium A mineral known to be essential; it activates a number of enzymes. Sufficiently widespread for human dietary deficiency to be unknown, and there are no estimates of requirements.

vanadium metallic element. XIX. — modL. vanadium, f. ON. Vanadis name of the Scand. goddess Freyja; see -IUM.

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