More than 20 million Americans, or 7% of the U.S. population, have diabetes.1 A recent survey noted that 44% of diabetic Americans were taking OTC supplements, usually in addition to their prescription medications.2 One product that has long been marketed as a nutritional supplement to aid in glucose management in diabetes is chromium picolinate.
Background
Chromium is a trace mineral required in small quantities by the body. It is found in many foods, including meat, animal fats, fish, brown sugar, coffee, tea, some spices, carrots, potatoes, broccoli, whole wheat and rye breads, and brewer’s yeast. While these foods are readily available, many American diets fail to provide adequate amounts of the mineral. Chromium enhances insulin function and helps the body metabolize carbohydrates and fats. Because of this role, chromium is also frequently marketed as a weight-loss or fat-burning supplement. Picolinate, an organic ligand, is thought to enhance absorption of chromium.
Mechanism of action
Chromium is thought to contribute to the control of insulin resistance, specifically in type 2 diabetics, because patients with that form of the disease have been found to lose more chromium in the urine than those without diabetes.3 In healthy individuals, naturally occurring chromium is absorbed in the GI tract in the levels required by the body. However, if disease states increase the loss of that element and dietary intake does not adequately make up for that loss, a state of deficiency may exist. Patients in intensive care settings with hyperglycemia that was poorly controlled showed significant improvements when total parenteral nutrition containing supplemental chromium was added to their treatment.3 The assumption was made that when chromium, which was deficient in the diabetic system, was supplemented, cellular uptake of systemic glucose was enhanced. Further studies suggested that the chromium itself acts at the site of the insulin receptors on the cell wall, thereby facilitating glucose transport across the cell wall and into the cytoplasmic contents.2
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When considering supplementation of a trace mineral, such as chromium, gut absorption is always a problem. Other elements, such as iron, are well known for their absorption difficulties and many different formulations of oral iron exist to specifically address that problem. Chromium has been found to be much better absorbed when it is bonded with picolinic acid,4 thereby producing the supplement in its form of chromium picolinate.
Scientific data
In a recent FDA report, claims of chromium picolinate’s efficacy in reducing insulin resistance were contradicted, mainly based on insufficient evidence.4 In its meta-analysis of 29 studies meeting appropriate criteria (randomized, controlled), only one study showed benefit for chromium picolinate and insulin resistance.4 Because of the small size of that study, FDA approval for this claim was not granted.4
It should be noted, however, that although the FDA rejected the claim, it did not deny that the study showed positive effect of the supplement and did indicate that further research was warranted.5 Numerous other small studies with varying designs exist, but none has the quality of methodology and strength of evidence necessary for a formal claim of efficacy. In a 2003 statement on dietary supplements and nutraceuticals, the American Association of Clinical Endocrinologists stated that “in patients with manifestations of chromium deficiency (hyperglycemia, hyperlipidemia, peripheral neuropathy, and low chromium levels)…the use of enteral or parenteral chromium therapy is clinically obvious.”2
As with many other supplements and nutraceuticals, the level of product impact on the disease process seems to be closely linked to the severity of the condition. One recent study found that chromium treatment in poorly controlled, insulin-treated type 2 diabetics was shown to have no effect.6
Dosage
The upper limit of dietary chromium intake is in the range of 50-200 µg per day.2 Since most American diets fall far below providing that range, the typical supplemental dose is 200 µg by mouth one to three times daily.2 The FDA has set an all-source recommended daily allowance of 120 µg of absorbed chromium per day.4
Side effects
Adverse effects are rare from the average amount of chromium consumed through diet or supplementation and may include headache, insomnia, and mood changes.7 Higher than normal doses, however, have been associated with anemia, thrombocytopenia, hemolysis, hepatic dysfunction, and renal failure.4 Animal studies have demonstrated weight gain and even DNA damage, although these results have not been seen in humans.7
Drug interactions
Concomitant use of niacin, frequently prescribed for hypertriglyceridemia, can potentiate the effects of chromium on glucose tolerance.4 Since chromium is not a botanical supplement, plant-based allergies would not be suspected, but different manufacturers using various capsule products could always be the source of a sensitivity reaction. Studies have not been conducted in children and pregnant or nursing women, and therefore, this product should not be used in those populations.
References
1. American Diabetes Association. Diabetes Statistics. Available at www.diabetes.org/diabetes-statistics.jsp. Accessed October 11, 2006.
2. American Association of Clinical Endocrinologists. American Association of Clinical Endocrinologists medical guidelines for the clinical use of dietary supplements and nutraceuticals. Endocr Pract. 2003;9:417-470.
3. Morelli V, Zoorob RJ. Alternative therapies: Part I. Depression, diabetes, obesity. Am Fam Physician. 2000;62:1051-1060.
4. U.S. Food and Drug Administration. Qualified Health Claims: Letter of Enforcement Discretion — Chromium Picolinate and Insulin Resistance (Docket No. 2004Q-0144). Available at www.cfsan.fda.gov/~dms/qhccr.html. Accessed October 11, 2006.
5. National Center for Complementary and Alternative Medicine/National Institutes of Health. Treating Type 2 Diabetes with Dietary Supplements. Available at nccam.nih.gov/health/diabetes. Accessed October 11, 2006.
6. Kleefstra N, Houweling ST, Jansman FG. et al. Chromium treatment has no effect in patients with poorly controlled, insulin-treated type 2 diabetes in an obese Western population: a randomized, double-blind, placebo-controlled trial. Diabetes Care. 2006;29:521-525.
7. Drug Digest. Chromium Picolinate. Available at www.drugdigest.org/DD/DVH/HerbsWho/0,3923,4036|Chromium %2BPicolinate,00.html. Accessed October 5, 2006.
