chromium
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Chromium

Chromium is a mineral that humans need in trace amounts. It is found in two forms: trivalent, which is biologically active and found in food, and hexavalent, a toxic form resulting from industrial pollution. Trivalent chromium is known to enhance insulin action. It is also involved with carbohydrate, fat and protein metabolism. Absorbed chromium is stored in the liver, spleen, soft tissue and bone.

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›  Health benefits

Chromium has long been of interest for its possible connection to several health conditions. Among the most active areas of research are in its uses in treating diabetes, lowering blood lipid levels, promoting weight loss and improving body composition.

Type 2 diabetes and glucose intolerance
Insulin resistance leads to higher-than-normal levels of glucose in the blood (hyperglycemia). A chromium deficiency impairs the body’s ability to use glucose to meet its energy needs and raises insulin requirements. It has been suggested that chromium supplements might help to control type 2 diabetes or the glucose and insulin responses in people at high risk of developing the disease. A meta-analysis assessed the effects of chromium supplements on three markers of diabetes in the blood: glucose, insulin and glycated hemoglobin. Chromium supplementation had no effect on glucose or insulin concentrations in subjects without diabetes, nor did it reduce these levels in subjects with diabetes.

Overall, the value of chromium supplements for diabetes is inconclusive and controversial. The American Diabetes Association states that there is insufficient evidence to support the routine use of chromium to improve glycemic control in people with diabetes. It further notes that there is no clear scientific evidence that vitamin and mineral supplementation benefits people with diabetes who do not have underlying nutritional deficiencies.

Lipid metabolism
The effects of chromium supplementation on blood lipid levels in humans are also inconclusive. In some studies, 150 to 1,000 micrograms per day has decreased total and low-density-lipoprotein (LDL or “bad”) cholesterol and triglyceride levels and increased concentrations of apolipoprotein A (a component of high-density-lipoprotein cholesterol known as HDL or “good” cholesterol) in subjects with atherosclerosis or elevated cholesterol or among those taking a beta-blocker drug. These findings are consistent with the results of earlier studies.

Body weight and composition
Chromium supplements are sometimes claimed to reduce body fat and increase lean muscle mass. Yet a recent review of 24 studies that examined the effects of 200 to 1,000 micrograms per day of chromium (in the form of chromium picolinate) on body mass or composition found no significant benefits. Another recent review of randomized, controlled clinical trials did find supplements of chromium picolinate to help with weight loss when compared with placebo, but the differences were small and of debatable clinical relevance.

›  How much do I need?

In 1989, the National Academy of Sciences came up with a safe intake range for chromium. From this, adequate intake levels were established. The amount needed depends on gender and age. Men ages 14 to 50 need about 35 micrograms daily; men age 50-plus need 30 micrograms. Women ages 14-plus need 24 to 25 micrograms daily. Pregnant women need 29 to 30 micrograms daily; breastfeeding women, 44 to 45 micrograms

Women usually consume on average between 23 to 29 micrograms of chromium per day from food, and adult men usually consume an average of 39 to 54 micrograms per day.

Few serious adverse effects have been linked to high intake of chromium, so the Institute of Medicine has not established a tolerable upper intake level (UL) for this mineral. Certain medications may interact with chromium, especially when taken on a regular basis. Before taking dietary supplements, check with your doctor or other qualified healthcare provider, especially if you take prescription or over-the-counter medications.

Reports of chromium deficiency in humans are rare. The body’s chromium content may be reduced under several conditions, though. Diets high in simple sugars (comprising more than 35 percent of calories) can increase chromium excretion in the urine. Infection, acute exercise, pregnancy and lactation, and stressful states (such as physical trauma) increase chromium losses and can lead to deficiency, especially if chromium intake is already low. Older people may be more vulnerable to chromium depletion than younger adults.

›  In food

Chromium is found in many foods, but usually only in small amounts (less than 2 micrograms per serving). Meat and whole-grain products, as well as some fruits, vegetables and spices, are good sources, while foods high in simple sugars are low in chromium. Dietary intakes are hard to determine because the content of chromium in food is substantially affected by agricultural and manufacturing practices.

›  Dietary supplements

Chromium is sold as a single-ingredient supplement, as well as in combination with other minerals or nutrients, especially those marketed for weight loss and performance enhancement. They can be available as chromium chloride, chromium nicotinate, high-chromium yeast and chromium citrate, but it is not clear which type is best to take. Vitamin C and niacin (vitamin B3) can enhance the body’s absorption of chromium.

Source: National Institutes of Health, Office of Dietary Supplements

Please consult your health care provider before making changes to your vitamin/supplement regimen.

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