Chromium
Overview:
Chromium is an essential mineral found in very low concentrations in the human body. In 1957, researchers discovered a compound extracted from pork kidney called glucose tolerance factor (GTF). Administration of GTF helped diabetic rats use insulin more efficiently. People with diabetes either do not produce enough insulin or cannot properly use the insulin that their bodies produce. Insulin is a hormone that is needed to convert sugar, starches and other food into energy needed for daily life. As a result, glucose or sugar builds up in the bloodstream. Chromium was later identified as the active component of GTF. Today, scientists believe that chromium helps insulin bring glucose from the blood into the cells for energy.
As many as 90% of American diets are low in chromium, but few people are deficient in this important mineral. The elderly, people who indulge in strenuous exercise, those who consume excessive amounts of sugary foods, and pregnant women are most likely to be deficient in chromium. Low chromium levels can increase blood sugar, triglycerides (a type of fat in the blood), cholesterol levels, and increase the risk for a number of conditions, such as diabetes and heart disease.
Good chromium food sources include whole grain breads and cereals, lean meats, cheeses, and some spices, such as black pepper and thyme. Brewer' s yeast is also rich in chromium.
Uses:
Clinical studies suggest that chromium supplementation may be helpful for the following conditions:
Diabetes
The benefit of chromium supplements for diabetes has been studied and debated for a number of years. While some clinical studies have reported no beneficial effects of chromium use for people with diabetes, other clinical studies have reported that chromium supplements may reduce blood sugar levels as well as the amount of insulin needed by people with diabetes. Pregnancy-induced and steroid-induced diabetes may benefit from chromium as well. Chromium was found to decrease the insulin resistance problems seen in individuals who smoke cigarettes. Chromium is an antioxidant, which helps protect the body against free radical damage (oxidation).
Because of the popularity of taking chromium supplements for blood sugar regulation, the U.S. Food and Drug Administration (FDA) reviewed the clinical evidence and concluded that the relationship between chromium picolinate intake and insulin resistance is highly uncertain. More research is needed.
Obesity
Some studies suggest that chromium may improve lean body mass (namely, muscle) and reduce body fat. However, despite the popularity of chromium (especially chromium picolinate) for weight loss, the effects are small compared to those of exercise and a well-balanced diet.
Strength training
Chromium is popular with some body builders and can be found in certain sports nutrition supplements. Despite this popularity, there is little clinical evidence that chromium supplementation changes body composition or helps people gain strength. This topic has been studied in several different groups of people, including athletic and nonathletic men and women as well as elderly men.
Heart health
Animal studies suggest that chromium may help improve blood pressure. This has yet to be tested on people. Until more information is available, use of chromium for this purpose is not recommended.
Although not all clinical studies agree, chromium has demonstrated the ability to lower total and low density lipoprotein (LDL or "bad") cholesterol levels and raise high density lipoprotein (HDL or "good") cholesterol levels in the blood, particularly in people with high cholesterol.
Animal studies show that chromium bound to niacin, or vitamin B3 protects the heart and increases energy levels.
Others
Preliminary clinical studies show that chromium picolinate improves symptoms of depression in people with atypical depression. More research is needed.
Dietary Sources:
Dietary sources of chromium include brewer's yeast, lean meats (especially processed meats), cheeses, pork kidney, whole-grain breads and cereals, molasses, spices, and some bran cereals.
Brewer's yeast (particularly yeast grown in chromium-rich soil) is a rich dietary source of chromium, as are organ meats, mushroom, oatmeal, prunes, nuts, asparagus, and whole grains and cereals.
Vegetables, fruits, and most refined and processed foods (except for processed meats) contain low amounts of chromium.
Available Forms:
Chromium is commercially available in several forms including chromium nicotinate, chromium histidinate, chromium picolinate, chromium-enriched yeast, chromium chloride, and glucose tolerance factor chromium (GTF). Chromium is available as part of many multivitamins or alone in tablet and capsule forms.
How to Take It:
Dosages of chromium are based on the Dietary Guidelines for Americans 2005 published by the U.S. Department of Health and Human Services and U.S. Department of Agriculture. The recommended dietary allowances (RDAs) of chromium are as follows:
Pediatric
For infants birth - 6 months: The RDA for chromium is 0.2 mcg (micrograms) daily.
For infants 7 - 12 months: The RDA for chromium is 5.5 mcg daily.
For children 1 - 3 years: The RDA for chromium is 11 mcg daily.
For children 4 - 8 years: The RDA for chromium is 15 mcg daily.
For male children 9 - 13 years: The RDA for chromium is 25 mcg daily.
For female children 9 - 13 years: The RDA for chromium is 21 mcg daily.
For male children 14 - 18 years: The RDA for chromium is 35 mcg daily.
For female children 14 - 18 years: The RDA for chromium is 24 mcg daily.
For pregnant females 14 - 18 years: The RDA for chromium is 29 mcg daily.
For breast-feeding females 14 - 18 years: The RDA for chromium is 44 mcg daily.
Adult
For adult males 19 - 50 years: The RDA for chromium is 35 mcg daily.
For adult males 51 years and older: The RDA for chromium is 30 mcg daily.
For adult females 19 - 50 years: The RDA for chromium is 25 mcg daily.
For adult females 50 years and older: The RDA for chromium is 20 mcg daily.
For pregnant females 19 years and older: The RDA for chromium is 30 mcg daily.
For breastfeeding females 19 years and older: The RDA for chromium is 30 mcg daily.
Chromium supplementation
For disease prevention and treatment, dosage in adults is typically 200 mcg chromium, 1 - 3 times a day. Type 2 diabetics may benefit from doses as high as 1,000 mcg daily, but long term safety with such high doses is not known.
Precautions:
Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider.
Although the type of chromium found in foods is generally considered safe, extremely high doses of this mineral can inhibit the effectiveness of insulin and cause stomach irritation, itching, and flushing. There have also been rare reports of fast, irregular heart rhythms and liver dysfunction from too much chromium. Two cases of kidney damage have been reported from the use of chromium picolinate supplements.
Dietary chromium, which is considered safe, is often confused with an unsafe industrial form of chromium (hexavalent chromium or chromium VI) that is readily absorbed by the lungs, digestive tract, mucous membranes, and skin. Chromium VI is a toxic industrial compound that is primarily encountered through occupational exposure by either direct contact or through inhalation of dust or aerosols.
Possible Interactions:
If you are currently being treated with any of the following medications, you should not use chromium without first talking to your health care provider:
Antacids -- Animal studies suggest that antacids, particularly those containing calcium carbonate (including Tums and Mylanta), may reduce the body's ability to absorb chromium. Although it is unclear how this research relates to people, it may be advisable to avoid taking chromium supplements at the same time as antacids.
Diabetes Medications -- Chromium supplements may actually enhance the effectiveness of certain diabetes medications. Clinical studies have demonstrated that people with type 1 or type 2 diabetes who take chromium supplements may require lower doses of insulin, metformin (Glucophage), or sulfonylureas (a group of medications used to treat type 2 diabetes including glyburide or Diabeta, glipizide or Glucotrol, and chlorpropamide or Diabenese).
- Reviewed last on: 3/20/2009
- Steven D. Ehrlich, NMD, private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network.
http://www.umm.edu/altmed/articles/chromium-000294.htm
University of Maryland Medical Center
