Chromium


Chromium Used to Help Blood Sugar, Metabolism. November 21, 2005.

Chromium is an essential trace mineral found in a variety of foods, including whole grains, cereals, spices (such as black pepper), broccoli, mushrooms, cheese, seafood and meat. In the body, it plays a role in metabolizing fats and carbohydrates and controlling blood levels of sugar.

The body has a hard time absorbing chromium supplements in mineral form; it is absorbed more easily when it's bound to another molecule. Chromium niacin, sometimes called niacin-bound chromium, is one form of so-called bioavailable chromium sold as a supplement: Another commonly sold form is chromium picolinate.

Uses: Chromium niacin (also known as chromium polynicotinate) and chromium picolinate are often taken for diabetes, weight loss, body building or, sometimes, to prevent heart disease.

Dose: The Institute of Medicine recommends a daily chromium intake of 25 to 45 micrograms. Most people get about 25 micrograms from food: Nutrition experts think that's sufficient (breastfeeding moms may need 45 micrograms). Supplement manufacturers recommend doses of 50 to 200 micrograms a day.

Precautions: The long-term safety of taking high doses of chromium is unknown. Chromium niacin appears safe in manufacturer-recommended doses but chromium picolinate has been linked to a few cases of kidney failure and liver damage. Animal studies suggest chromium picolinate has cancer-causing potential.

Research: In lab studies, animals deprived of chromium become glucose intolerant: Their bodies fail to efficiently remove sugar from their blood. Research published in the late 1970s showed that people deprived of chromium developed diabetes-like symptoms, which were reversed following chromium supplementation. But the supplements won't necessarily help people who aren't chromium-deprived. A 2002 review of 15 clinical trials, published in the American Journal of Clinical Nutrition, concluded that the supplement didn't improve glucose or insulin levels in people with Type 2 diabetes. Animal tests have suggested chromium may help lower cholesterol levels and protect against heart disease. Human findings are mixed: A 2005 study published in the American Journal of Epidemiology linked low chromium levels to increased heart disease risk in men.

Dozens of studies on chromium picolinate and weight control are inconclusive: Some have reported that the supplement helps with weight loss, others that it doesn't. Chromium niacin's role in weight loss is less studied. A small clinical trial in India, published in 2004 in the journal Diabetes, Obesity and Metabolism, showed that chromium niacin, taken with hydroxycitric acid and the herb Gymnema sylvestre for eight weeks, decreased body weight by an average of 5% in obese subjects. More studies are needed to confirm this effect.


Other Studies

1. Anderson RA, Cheng N, Bryden NA, Polansky MM, Cheng N, Chi J, Feng J. Elevated intakes of supplemental chromium improve glucose and insulin variables in individuals with type 2 diabetes. Diabetes. 1997 Nov;46(11):1786-91.

Chromium is an essential nutrient involved in normal carbohydrate and lipid metabolism. The chromium requirement is postulated to increase with increased glucose intolerance and diabetes. The objective of this study was to test the hypothesis that the elevated intake of supplemental chromium is involved in the control of type 2 diabetes. Individuals being treated for type 2 diabetes (180 men and women) were divided randomly into three groups and supplemented with: 1) placebo, 2) 1.92 micromol (100 microg) Cr as chromium picolinate two times per day, or 3) 9.6 micromol (500 microg) Cr two times per day. Subjects continued to take their normal medications and were instructed not to change their normal eating and living habits. HbA1c values improved significantly after 2 months in the group receiving 19.2 pmol (1,000 microg) Cr per day and was lower in both chromium groups after 4 months (placebo, 8.5 +/- 0.2%; 3.85 micromol Cr, 7.5 +/- 0.2%; 19.2 micromol Cr, 6.6 +/- 0.1%). Fasting glucose was lower in the 19.2-micromol group after 2 and 4 months (4-month values: placebo, 8.8 +/- 0.3 mmol/l; 19.2 micromol Cr, 7.1 +/- 0.2 mmol/l).

Two-hour glucose values were also significantly lower for the subjects consuming 19.2 micromol supplemental Cr after both 2 and 4 months (4-month values: placebo, 12.3 +/- 0.4 mmo/l; 19.2 micromol Cr, 10.5 +/- 0.2 mmol/l). Fasting and 2-h insulin values decreased significantly in both groups receiving supplemental chromium after 2 and 4 months. Plasma total cholesterol also decreased after 4 months in the subjects receiving 19.2 micromol/day Cr. These data demonstrate that supplemental chromium had significant beneficial effects on HbA1c, glucose, insulin, and cholesterol variables in subjects with type 2 diabetes. The beneficial effects of chromium in individuals with diabetes were observed at levels higher than the upper limit of the Estimated Safe and Adequate Daily Dietary Intake.

2. Morris BW, MacNeil S, Hardisty CA, Heller S, Burgin C, Gray TA. Chromium homeostasis in patients with type II (NIDDM) diabetes. J Trace Elem Med Biol. 1999 Jul;13(1-2):57-61.

The purpose of this study was to assess chromium handling in non-insulin dependent diabetic patients (NIDDM) compared to healthy volunteers. Chromium handling was evaluated using fasting blood and second morning void urine samples from 93 NIDDM patients and 33 healthy volunteers. Significant differences in chromium homeostasis were seen between patients and controls. NIDDM patients had mean levels of plasma chromium around 33% lower and urine values almost 100% higher than those found in health. Healthy volunteers showed a significant negative correlation between fasting levels of plasma chromium and insulin. This was not evident in NIDDM patients. In the early years of onset of NIDDM, plasma chromium values were inversely correlated with plasma glucose. This was lost in patients with diabetes of more than 2 years duration. We suggest large losses of chromium over many years may exacerbate an already compromised chromium status in NIDDM patients and might contribute to the developing insulin resistance seen in patients with type 2 diabetes.

3. A scientific review: the role of chromium in insulin resistance. Diabetes Educ. 2004;Suppl:2-14.

Chromium is an essential mineral that appears to have a beneficial role in the regulation of insulin action and its effects on carbohydrate, protein and lipid metabolism. Chromium is an important factor for enhancing insulin activity. Studies show that people with type 2 diabetes have lower blood levels of chromium than those without the disease. Insulin resistance is the common denominator in a cluster of cardiovascular disease risk factors. One out of every five Americans has metabolic syndrome. It affects 40% of people in their 60s and 70s. Insulin resistance, with or without the presence of metabolic syndrome, significantly increases the risk of cardiovascular disease. Insulin resistance is present in two serious health problems in women; polycystic ovarian syndrome (PCOS) and gestational diabetes. Several studies have now demonstrated that chromium supplements enhance the metabolic action of insulin and lower some of the risk factors for cardiovascular disease, particularly in overweight individuals. Chromium picolinate, specifically, has been shown to reduce insulin resistance and to help reduce the risk of cardiovascular disease and type 2 diabetes. Dietary chromium is poorly absorbed. Chromium levels decrease with age. Supplements containing 200-1,000 mcg chromium as chromium picolinate a day have been found to improve blood glucose control. Chromium picolinate is the most efficacious form of chromium supplementation. Numerous animal studies and human clinical trials have demonstrated that chromium picolinate supplements are safe.

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