Chromium

Description

Chromium is a mineral that is essential to humans. It is found naturally in a variety of foods, and supplements are available in capsules or tablets. Supplements are prepared using a number of formulas, including chromium (III), chromium aspartate, chromium chloride, chromium citrate, chromium nicotinate, chromium picolinate, GTF chromium, and trivalent chromium.

General use

Chromium supports the normal function of insulin, which is a hormone secreted by the pancreas. Insulin helps transport glucose from the bloodstream into liver, muscle, and fat cells. Once it is inside these cells, the sugar is metabolized into a source of energy. Insulin is also involved in regulating protein, fat, and catalytic enzyme processes. People with diabetes do not produce insulin (or produce very little) or their bodies cannot properly use the insulin that is produced. As a result, sugar builds up in the bloodstream, causing serious health effects. Numerous scientific studies have shown that chromium is useful in treating insulin resistance (metabolic syndrome) and diabetes. Diabetic peripheral neuropathy , a form of nerve damage that is a direct result of diabetes, is indirectly related to a lack of sufficient chromium.

Several studies have shown that chromium supplements may improve insulin sensitivity, and lower blood glucose and elevated body fat. In February 2004, the University of Pennsylvania School of Medicine began a comprehensive study of chromium as a therapy for insulin resistance. This condition occurs when the body fails to respond properly to the insulin it already produces. People who are insulin resistant may have the ability to overcome this problem by producing more insulin. However, if the body cannot produce sufficient amounts of insulin, glucose levels in the bloodstream rise, and type 2 diabetes ultimately occurs. It is estimated that up to 80 million Americans have insulin resistance.

A study conducted by Isala Clinics and University Hospital Groningen in the Netherlands, and released in 2003, showed that a daily dose of 1,000 micrograms of chromium significantly reduced blood sugar levels in people with poorly controlled type 2 diabetes who use insulin.

Chromium has also been used as an effective treatment for polycystic ovarian syndrome (PCOS), a hormonal condition affecting about two million American women. The condition can lead to infertility if untreated, and is associated with insulin resistance and type 2 diabetes. A study released in 2003 by the State University of New York at Stony Brook showed that insulin sensitivity increased an average of 35 percent after two months of daily treatment with 1,000 micrograms (μg) of chromium.

Through its involvement with insulin function, chromium plays an indirect role in lowering blood lipids. Studies suggest, but have not proven, that chromium supplementation can reduce the risk of cardiovascular (heart) disease in men, and may decrease total cholesterol and triglyceride levels. However, several studies contradict these claims. Studies in animals suggest chromium supplementation may reduce hypertension (high blood pressure). Lipid reduction is secondary to insulin regulation and control; therefore, persons whose insulin is well regulated and controlled may not achieve reduced heart disease risk by taking chromium supplements.

Chromium supplements in high doses—1,000 g or more a day—are sometimes used in weight loss and muscle development. However, a number of scientific studies have found that chromium supplements are not effective in these areas. In fact, precautions warn against chromium doses exceeding 1,000 g per day. Weight loss and muscle development are secondary to insulin regulation and control. Therefore, when insulin is well regulated and controlled, chromium may not impact weight loss or muscle development.

Preparations

A complete lack of chromium is rare, and the United States Food and Drug Administration (FDA) has not established recommended dietary allowances (RDA) for the mineral. However, national statistics on the prevalence of diabetes, heart disease, and obesity suggest that chromium deficiencies may be common. Chromium occurs naturally in meat, seafood, dairy products, eggs, whole grains, black pepper, and almonds. According to The PDR Family Guide to Natural Medicines and Healing Therapies, the usual chromium supplement dose for children ages seven and older and adults is 50–200 g a day in tablets or capsules. For persons with type 2 diabetes who are not taking insulin, doses from 200–1,000 g daily may be taken. However, persons should only take doses at these levels after consulting with a physician. Chromium should not be taken in doses exceeding 1,000 g a day. The cost of a bottle of 100 tablets or capsules (200 g) of chromium picolinate ranges from $5 to $10.

Precautions

Doses of 200–1,000 g of chromium should be taken only after consultation with a physician. Pregnant or breastfeeding women are advised to consult a physician before taking chromium supplements. Chromium should not be taken in doses exceeding 1,000 g a day. Increased dietary sugar may be associated with higher urinary excretion of chromium.

Side effects

Several studies have noted occasional reports of irregular heartbeats with chromium use. Infrequently, chromium has been reported to cause such sleep pattern changes as insomnia and increased dream activity. Irritability has also been reported. In rare instances, persons may be allergic to a chromium formula. The symptoms of an allergic reaction include difficulty breathing, chest pain, hives , rash, and itchy or swollen skin. If this happens, the patient is advised to seek medical care immediately. High doses may also cause liver and kidney damage, or gastric irritation, although these side effects are rare.

Interactions

Persons who are taking antacids are advised to talk with a physician before taking chromium supplements. Studies in animals suggest that antacids, especially those containing calcium carbonate, may reduce the body's ability to absorb chromium. Studies have shown that chromium may enhance the effectiveness of drugs taken by people who have type 2 diabetes or insulin resistance. These drugs include glimepiride, glipizide, glyburide, insulin, and metformin. Individuals taking these drugs should discuss chromium supplementation with a physician because improved insulin function may necessitate medication dosage changes.

Resources

BOOKS

Brown, Donald J. Herbal Prescriptions for Health and Healing: Your Everyday Guide to Using Herbs Safely and Effectively. Twin Lakes, WI: Lotus Press, 2003.

Evans, Gary. All About Chromium Picolinate: Frequently Asked Questions. Garden City Park, NY: Avery, 1999.

Icon Health Publications. Chromium Picolinate: A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References. San Diego, CA: Icon Health Publications, 2003.

Kamen, Betty. The Chromium Connection: A lesson in Nutrition. Novato, CA: Nutrition Encounter Inc., 1995.

Passwater, Richard A. Chromium Picolinate. New York, NY: McGraw-Hill/Contemporary Books; Reprint Edition, 1995.

PERIODICALS

Biotech Week Editors and Staff. "Company Seeks FDA Approval of Health Claims for Chromium." Biotech Week (January 28, 2004): 308.

"Chromium." UC Berkeley Wellness Letter (July 2003): 3.

Drug Week Editors and Staff. "Chromium Picolinate May Benefit Patients with Insulin Resistance." Drug Week (December 26, 2003): 121.

Drug Week Editors and Staff. "Research: Lower Chromium Levels Linked to Increased Risk of Disease." Drug Week (April 2, 2004): 263.

Lamson, Davis W., and Steven M. Plaza. "The Safety and Efficacy of High-Dose Chromium. Alternative Medicine Review (June 2002): 218–236.

Lydic, Michael L., et al. "Effects of Chromium Supplementation on Insulin Sensitivity and Reproductive Function in Polycystic Ovarian Syndrome: A Pilot Study." Fertility and Sterility (Supplement 3) (September 2003): 45–46.

Volpe, Stella L., et al. "Effect of Chromium Supplementation and Exercise on Body Composition, Resting Metabolic Rate, and Selected Biochemical Parameters in Moderately Obese Women Following an Exercise Program." Journal of the American College of Nutrition (August 2001): 293–306.

Ward, Elizabeth M. "Top 10 Supplements for Men." Men's Health (December 2003): 106.

Ken R. Wells

Chromium

Definition

Purpose

Description

Precautions

Interactions

Complications

Resources

Definition

Chromium is a mineral that is essential to humans It is found naturally in a variety of foods, and supplements are available in capsules or tablets. Supplements are prepared using a number of formulas, including chromium (III), chromium aspartate, chromium chloride, chromium citrate, chromium nicotinate,

Chromium

(Illustration by GGS Information Services/Thomson Gale.)

chromium picolinate, GTF chromium, and trivalent chromium.

Purpose

Chromium supports the normal function of insulin, which is a hormone secreted by the pancreas. Insulin helps transport glucose from the bloodstream into liver, muscle, and fat cells. Once it is inside these cells, the sugar is metabolized into a source of energy. Insulin is also involved in regulating protein, fat, and catalytic enzyme processes. People with diabetes do not produce insulin (or produce very little) or their bodies cannot properly use the insulin that is produced. As a result, sugar builds up in the bloodstream, causing serious health effects. Numerous scientific studies have shown that chromium is useful in treating insulin resistance (metabolic syndrome) and diabetes. Diabetic peripheral neuropathy, a form of nerve damage that is a direct result of diabetes, is indirectly related to a lack of sufficient chromium.

Description

Several studies have shown that chromium supplements may improve insulin sensitivity, and lower blood glucose and elevated body fat. In February 2004, the University of Pennsylvania School of Medicine began a comprehensive study of chromium as a therapy for insulin resistance. This condition occurs when the body fails to respond properly to the insulin it already produces. People who are insulin resistant may have the ability to overcome this problem by producing more insulin. However, if the body cannot produce sufficient amounts of insulin, glucose levels in the bloodstream rise, and type 2 diabetes ultimately occurs. It is estimated that up to 80 million Americans have insulin resistance.

A study conducted by Isala Clinics and University Hospital Groningen in the Netherlands, and released in 2003, showed that a daily dose of 1,000 micrograms of chromium significantly reduced blood sugar levels in people with poorly controlled type 2 diabetes who use insulin.

Chromium has also been used as an effective treatment for polycystic ovarian syndrome (PCOS), a hormonal condition affecting about two million American women. The condition can lead to infertility if untreated, and is associated with insulin resistance and type 2 diabetes. A study released in 2003 by the State University of New York at Stony Brook showed that insulin sensitivity increased an average of 35% after two months of daily treatment with 1,000 micro-grams (mcg) of chromium.

Through its involvement with insulin function, chromium plays an indirect role in lowering blood lipids. Studies suggest, but have not proven, that chromium supplementation can reduce the risk of cardiovascular (heart) disease in men, and may decrease total cholesterol and triglyceride levels. However, several studies contradict these claims. Studies in animals suggest chromium supplementation may reduce hypertension (high blood pressure). Lipid reduction is secondary to insulin regulation and control; therefore, persons whose insulin is well regulated and controlled may not achieve reduced heart disease risk by taking chromium supplements.

Chromium supplements in high doses—1,000 mcg or more a day—are sometimes used in weight loss and muscle development. However, a number of scientific studies have found that chromium supplements are not effective in these areas. In fact, precautions warn against chromium doses exceeding 1,000 mcg per day. Weight loss and muscle development are secondary to insulin regulation and control. Therefore, when insulin

KEY TERMS

Calcium carbonate —A salt that is used in many antacids.

YDiabetes —Several metabolic disorders in which the body produces insufficient insulin.

Glucose —Sugar.

Hypertension —High blood pressure, which, if untreated, can lead to heart disease and stroke.

Insomnia —The inability to sleep.

Insulin —A hormone that helps liver, muscle and fat cells take up sugars, starches, and other foods for conversion into energy the body needs.

Insulin resistance1 —Also called metabolic syndrome, a condition in which the body fails to properly respond to the insulin it produces.

Polycystic ovarian syndrome —PCOS, a hormonal condition in women that if untreated can lead to the inability to have children.

is well regulated and controlled, chromium may not impact weight loss or muscle development.

A complete lack of chromium is rare, and the United States Food and Drug Administration (FDA) has not established recommended dietary allowances (RDA) for the mineral. However, national statistics on the prevalence of diabetes, heart disease, and obesity suggest that chromium deficiencies may be common. Chromium occurs naturally in meat, seafood, dairy products, eggs, whole grains, black pepper, and almonds. According to The PDR Family Guide to Natural Medicines and Healing Therapies, the usual chromium supplement dose for children ages seven and older and adults is 50–200 mcg a day in tablets or capsules. For persons with type 2 diabetes who are not taking insulin, doses from 200–1,000 mcg daily may be taken. However, persons should only take doses at these levels after consulting with a physician. Chromium should not be taken in doses exceeding 1,000 mcg a day. The cost of a bottle of 100 tablets or capsules (200 mcg) of chromium picolinate ranges from $5 to $10.

Precautions

Doses of 200–1,000 mcg of chromium should be taken only after consultation with a physician. Pregnant or breastfeeding women are advised to consult a physician before taking chromium supplements. Chromium should not be taken in doses exceeding 1,000 mcg a day. Increased dietary sugar may be associated with higher urinary excretion of chromium.

Interactions

Persons who are taking antacids are advised to talk with a physician before taking chromium supplements. Studies in animals suggest that antacids, especially those containing calcium carbonate, may reduce the body’s ability to absorb chromium. Studies have shown that chromium may enhance the effectiveness of drugs taken by people who have type 2 diabetes or insulin resistance. These drugs include glimepiride, glipizide, glyburide, insulin, and metformin. Individuals taking these drugs should discuss chromium supplementation with a physician because improved insulin function may necessitate medication dosage changes.

Complications

Several studies have noted occasional reports of irregular heartbeats with chromium use. Infrequently, chromium has been reported to cause such sleep pattern changes as insomnia and increased dream activity. Irritability has also been reported. In rare instances, persons may be allergic to a chromium formula. The symptoms of an allergic reaction include difficulty breathing, chest pain, hives, rash, and itchy or swollen skin. If this happens, the patient is advised to seek medical care immediately. High doses may also cause liver and kidney damage, or gastric irritation, although these side effects are rare.

Resources

BOOKS

Brown, Donald J. Herbal Prescriptions for Health and Healing: Your Everyday Guide to Using Herbs Safely and Effectively Twin Lakes, WI: Lotus Press, 2003.

Evans, Gary. All About Chromium Picolinate: Frequently Asked Questions Garden City Park, NY: Avery, 1999.

Icon Health Publications. Chromium Picolinate: A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References San Diego, CA: Icon Health Publications, 2003.

Kamen, Betty. The Chromium Connection: A lesson in Nutrition Novato, CA: Nutrition Encounter Inc., 1995.

Passwater, Richard A. Chromium Picolinate New York,NY: McGraw-Hill/Contemporary Books; Reprint Edition, 1995.

PERIODICALS

Biotech Week Editors and Staff. “Company Seeks FDA Approval of Health Claims for Chromium.” Biotech Week (January 28, 2004): 308. “Chromium.” UC Berkeley Wellness Letter (July 2003): 3.

Drug Week Editors and Staff. “Chromium Picolinate May Benefit Patients with Insulin Resistance.” Drug Week (December 26, 2003): 121.

Drug Week Editors and Staff. “Research: Lower Chromium Levels Linked to Increased Risk of Disease.” Drug Week (April 2, 2004): 263.

Lamson, Davis W., and Steven M. Plaza. “The Safety and Efficacy of High-Dose Chromium. Alternative Medicine Review (June 2002): 218–236.

Lydic, Michael L., et al. “Effects of Chromium Supplementation on Insulin Sensitivity and Reproductive Function in Polycystic Ovarian Syndrome: A Pilot Study.” Fertility and Sterility (Supplement 3) (September 2003): 45–46.

Volpe, Stella L., et al. “Effect of Chromium Supplementation and Exercise on Body Composition, Resting Metabolic Rate, and Selected Biochemical Parameters in Moderately Obese Women Following an Exercise Program.” Journal of the American College of Nutrition (August 2001): 293–306.

Ward, Elizabeth M. “Top 10 Supplements for Men.” Men’s Health (December 2003): 106.

Ken R. Wells

Chromium

melting point: 1,860°C
boiling point: 2,670°C
density: 7.19 g/cm³
most common ions: Cr²⁺, Cr³⁺, CrO₄²⁻, Cr₂O₇²⁻

Chromium was first identified in 1797 by the French chemist Louis-Nicolas Vauquelin, who isolated it from crocoite, a mineral also called Siberian red lead. The name for chromium is taken from the Greek chroma, which means "color." This is a fitting name, because chromium compounds are often found in vividly colorful shades of green, red, or yellow. As such, chromium compounds historically have found extensive use as pigments for paints. In contrast, elemental chromium is a shiny, hard, yet brittle, steel-gray metal . Since chromium is not found naturally in its free elemental state, it is usually extracted from chromite, FeCr₂O₄.

Perhaps the best-known use of chromium is as a decorative, protective, shiny plating over other metals, with chrome-plated automobile parts being a familiar example. Chromium is also an important alloy component in stainless steel because it makes the steel stronger and more corrosion-resistant. Paint pigments account for more than one-third of all chromium usage each year.

Overall, chromium is the twenty-first most abundant element in Earth's crust. It is usually found in the +2 (e.g., CrO), +3 (e.g., Cr₂O₃), or +6 (e.g., K₂Cr₂O₇) oxidation states, with chromic oxide, Cr₂O₃, being the ninth most abundant compound in Earth's crust. While chromium is considered a necessary micronutrient in human diets, many of its compounds are quite toxic. This is especially true of chromium in the +6 oxidation state, with compounds such as K₂Cr₂O₇ being identified as carcinogens. Thus chromium compounds should be handled carefully.

David A. Dobberpuhl

Bibliography

Heiserman, David L. (1992). Exploring Chemical Elements and Their Compounds. Blue Ridge Summit, PA: Tab Books.

Krebs, Robert E. (1998). The History and Use of Our Earth's Chemical Elements: A Reference Guide. Westport, CT: Greenwood Press.

Swertka, Albert (2002). A Guide to the Elements. New York: Oxford University Press.

chromium. Metallic element discovered independently by Louis-Nicolas Vauquelin (1763–1829) and Martin Heinrich Klaproth (1743–1817) in 1798, but not isolated until 1859 by Friedrich Wöhler (1800–82). Despite its attractive, bright, shiny, silvery appearance, and its reluctance to corrode, it was not much used until it was employed in the armaments industry during the 1914–18 war. From the 1920s it was produced commercially, and was used for plating on steel or copper (notably for the automobile industry), and was favoured by several Modernist architects for both buildings (e.g. Mies van der Rohe for the casings of columns in both the Barcelona Pavilion and the Tugendhat House) and furniture (e.g. the tubular steel frames of chairs of the period). It was widely used for Art-Deco work.

Bibliography

C. Benton et al. (eds.) (2003)

chromium A metallic element that is a dietary essential. It forms an organic complex with nicotinic acid, known as the glucose tolerance factor, which facilitates the interaction of insulin with receptors on cell surfaces. Deficiency results in impaired glucose tolerance.

There is little evidence on which to base estimates of requirements; deficiency has been observed at intakes below 6 μg (0.12 μmol)/day; the US/Canadian adequate intake is 35 μg for men and 25 μg for women. High intakes of inorganic chromium salts (in excess of 1–2 mg/day) are associated with kidney and liver damage.