Drug Criteria & Outcomes: Can chromium be used for diabetes?

By Charlotte Edmondson, PharmD candidate
Harrison School of Pharmacy
Auburn (AL) University

In today’s world of nutraceuticals and self-care, we as practitioners must keep up with the latest information on the uses of nutritional supplements to help our patients make decisions about their use. Diabetes is the seventh-leading cause of death in the United States, with 16 million people in this country affected by the disease. Because of the wide variety of complications that can be life-changing, it is important to keep tight control on glucose levels.

Chromium is currently being touted as a supplement for diabetic patients to increase control of their blood glucose levels. When searching the Internet for chromium’s use in diabetes, 52,000 citations were found, and 27 articles were found on Medline. Due to this vast array of information about chromium available to patients, we as practitioners must be aware of the clinical effects of this dietary supplement.

Chromium was thought to be essential in body processes prior to 1977 when a landmark case confirmed this importance. A woman on total parenteral nutrition (TPN) developed severe diabetic symptoms that could not be controlled with insulin. Upon further evaluation, physicians noted a deficiency in chromium, which is normally supplied in foods such as organ meats, mushrooms, wheat germ, broccoli, and processed meat products. After adding only a small amount of chromium (<50mcg) to the TPN, the symptoms subsided, and the patient’s blood glucose level returned to normal. The U.S. Food and Drug Administration (FDA) and the Food and Nutrition Board of the National Research Council then designated chromium as an essential nutritional trace element. This case led researchers to begin investigating the role of chromium in insulin-resistant type II diabetes mellitus (DM).

Chromium is an element found in the body; it is believed to work with insulin to transport glucose into cells. The mechanism by which this is thought to take place involves chromium increasing insulin binding to cells, increasing the number of insulin receptors, and activating insulin receptor kinase, leading to increased insulin sensitivity. Due to this mechanism, chromium would not be useful in insulin-dependent diabetes. Insulin resistance seems to be the focal point of the research. Additionally, chromium has been investigated in steroid-induced diabetes and gestational diabetes as well as other disease states such as obesity and hyperlipidemia.

Many studies have investigated the use of chromium in insulin-resistant diabetes mellitus. The results are varied but point in a favorable direction for the benefit of chromium; however, most of the trials involve small sample sizes, and only a few are well-controlled clinical trials. Dosage and salt forms also contribute to the variations in the results. The chromium picolinate and chloride salt forms have been most widely studied, with the picolinate form showing the most efficacy due to increased absorption. The most common dosages studied include 200 mcg, 600 mcg, and 1000 mcg daily.

One of the strongest trials, by Anderson et al1, was conducted in Beijing, China, with a total of 180 diabetic patients. The patients were 35-65 years of age, free of other disease, and had a fasting blood glucose concentration of 7.2-15.5 mmol/l (130-279mg/dL) with an HbA1c ranging from 8.0-12.0%. Patients were randomized into three groups, each with 60 individuals, with groups receiving chromium picolinate — either 200 mcg/d in two doses or 1000 mcg/d in two doses — or placebo. All of the groups were similar in many ways. After four months of treatment, the two active groups demonstrated a significant decrease in fasting glucose, two-hour glucose challenge tests, fasting insulin, two-hour insulin, and HbA1c measurements. The 1,000 mcg/d dose demonstrated the most clinically significant decreases in glucose levels. This trial supports the use of 1,000 mcg/d of chromium picolinate and reported no side effects. Weaknesses of this trial include all subjects being Chinese and glucose levels not being reported. Because the Chinese population has a lower incidence of obesity and diabetes, it is difficult to extrapolate these data to other populations.

Many of the other trials have assessed the use of chromium in diabetes. Bahadori et al2 investigated chromium picolinate’s effects on insulin levels and glucose control in obese patients with type II DM. Sixteen patients with a mean age of 56 years of age and body mass index of 32 kg/m2 were stabilized on sulfonylurea and metformin before receiving 500 mcg BID of chromium picolinate for four months. This trial, as well as many others, only reported outcomes as decreases in insulin levels, which the authors concluded might not support the use of this supplement. There were no changes in body weight, HbA1c, or steady-state glucose levels from baseline. This study also has a small sample size and was not placebo-controlled, blinded, or randomized.

In general, due to weak study design and large variability in results, the data from individual trials is not strong enough to recommend the use of chromium to better control hyperglycemia. However, when all of the results are combined, they suggest chromium may be efficacious. Studies using stronger study design are needed. None of the studies to date reported any serious side effects; those that were reported were minor and generally limited to effects that could be explained by other causes, such as hypoglycemia or rash that could be due to excipients in the particular brand of chromium. The literature suggests discontinuing use of the supplement if effects do not subside with continued use or changing brands.

Also, chromium supplements are rather inexpensive, ranging from $5-$15 per month. Of the two forms, picolinate appears to be the most efficacious, and 1,000 mcg/d provided the most benefit in clinical trials. Due to its proposed mechanism of action, some experts believe that chromium should show more of a benefit; with stronger studies, these benefits may be demonstrated. Long-term use has not been sufficiently studied. However, Cheng et al3 performed a follow-up survey of the trial in China discussed above and found no side effects at one year. Presently, for patients who are insulin-resistant, refractory to other hypoglycemic medications, and maintaining a healthy diet and regular exercise program, chromium picolinate may provide added glucose control. Patients’ questions about chromium’s use in diabetes give practitioners an opportunity for diabetic education and monitoring, as well as for informing the patient about the correct dose, possible side effects, and the benefits of chromium for better control of glucose levels.

References

1. Anderson RA, Cheng N, et al. Elevated intakes of supplemental chromium improve glucose and insulin variables in individuals with type-II diabetes. Diabetes 1997; 46:1786-1791.

2. Bahadori B, Wallner S, et al. Effects of chromium picolinate on insulin levels and glucose control in obese patients with type-II diabetes mellitus. Diabetes 1999; 48 (Supplement 1):A349.

3. Cheng N, Xixing Z, et al. Follow-up survey of people in China with type-II diabetes mellitus consuming supplemental chromium. J Trace Elem Experimental Medicine 1999; 12:55-60.

4. Natural Medicines Comprehensive Database available at http://naturaldatabase.com. Accessed Nov. 6, 2001.

5. Chromium in the prevention and control of diabetes available at www.veritasmedicine.com. Accessed Nov. 6, 2001.

6. Chromium Micromedex available at http://micromedex.duc.auburn.edu. Accessed Nov. 6, 2001.

7. American Diabetes Association available from URL: www.diabetes.org. Accessed Nov. 26, 2001.