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Perhaps Good, Perhaps Harmful

By David Mendosa

Posted On: June 18, 2003
Last Update: April 6, 2006

Chromium seems to be like the drug that Leonard Cohen sings about in his great song, The Butcher.

‘It did some good, did some harm.’
  Leonard Cohen, ‘The Butcher’

Recent studies have linked type 2 diabetes and chromium. But the most common form of the supplement, chromium picolinate, may be dangerous to your health. The second most common form, GTF chromium—for glucose tolerance factor—probably doesn’t exist. There are safety concerns about the third most common form, chromium polynicotinate—sometimes known as nicotinate.

It Does Some Harm
Researchers have several concerns about the picolinate form of chromium. Since it can alter levels of neurotransmitters, some experts think that it might harm individuals with depression, bipolar disease, or schizophrenia. A report of a severe skin reaction caused by chromium picolinate is another concern. It is also possible, but not proven, that chromium picolinate could cause adverse effects on DNA.

The concerns over the second most common form of chromium, GTF chromium, are not so serious and in fact would be laughable if fewer people hadn’t been deceived. It was in 1959 that Walter Mertz and his associates seemed to have demonstrated that chromium helped glucose to enter cells body by first converting chromium into a large chemical called glucose tolerance factor. They thought to be present in foods like brewer's yeast, which they described as superior sources of chromium. It turned out, however, that the process of chemical analysis was creating GTF.

“There is no doubt that GTF is an artifact,” University of Alabama Chemistry Professor John Vincent wrote me recently. Dr. Vincent is the leading expert working at present on the chemistry of chromium.

“I personally would not use chromium picolinate,” he wrote me in a separate email message. “The problem with the ‘GTF’ chromium is knowing what each company means by the term; depending on this, I might use the product. Chromium nicotinate and chromium polynicotinate are the same thing; however, this material is poorly defined as well. Some recent concerns have been raised, although they are not convincing as yet—more study is needed.”

It Does Some Good
Still, chromium supplementation may well do some good. Already in 1999, the most recent year for which data is available, retail sales of chromium picolinate exceeded half a billion dollars annually, according to Chemical Market Reporter. If you search the online vitamin (and mineral) retailer Vitamin Shoppe for “chromium picolinate,” it finds 58 matching products. If you expand the search for all chromium products, it finds 132 matching products.

In fact, there is surprisingly little evidence that chromium is essential to humans. The only solid evidence comes from studies of patients on total parental nutrition (TPN). Some of them develop impaired glucose utilization or glucose intolerance and neuropathy or encephalopathy. Infusing the patients with chromium reversed the symptoms. But this affected only four patients.

Even worse, these symptoms that chromium reversed in four patients did not correlate with serum chromium levels. Consequently, scientists don’t know of any indicator of chromium deficiency besides the reversal of symptoms.

After dozens of studies, the consensus is that chromium supplementation has no effect on glucose, insulin, or blood lipids. Using chromium supplements for 6 to 16 weeks in various studies has had no effect on people with diabetes. It remains possible, however, that longer term or high-dose studies could help.

Dr. Richard A. Anderson, a research chemist at the USDA-ARS Nutrient Requirements and Functions Laboratory in Beltsville, Maryland, led the study that grabbed the most recent attention. He and his co-workers studied 180 people with type 2 diabetes in China. For four months, they received supplements of chromium picolinate in doses of 0, 100, or 500 mg. At the end of the double blind, placebo-controlled study, the symptoms of those taking the supplements improved more than the control group. However, since the body mass indexes of the Chinese patients differ significantly from the typical American with type 2 diabetes, researchers have called for similar studies here.

The Food and Nutrition Board of Institute of Medicine sets the Estimated Average Requirement (EAR) in the United States. But the EAR issued last year found insufficient evidence to set one for chromium. Instead, the board set an “Adequate Intake” based on estimated mean intakes. It is 30-35 µg/day and 20-25 µg/day for men and women respectively. The board says that natural sources of chromium include some cereals, meats, poultry, fish, and beer.

If you are still determined to use a chromium supplement, you have another choice—chromium chloride. However, for some reason that I don’t understand, I was able to find it in only multivitamin and mineral formulations, including three Twinlab products. “It is also the form used in One-A-Day and Centrum multivitamins (although at least one special formula One-A- day uses chromium picolinate),” Dr. Vincent tells me. “I would have no hesitation taking chromium chloride at supplement levels.”

Latest Research
William Cefalu at the Medical School of the University of Vermont has received funding from the National Institutes of Health to perform a reasonably large human study to address effects of chromium on people with diabetes in this country. This should help decide whether chromium supplementation has any effect.

“I am still open to the possibility that small positive effects could result from chromium supplementation of people with altered glucose metabolism,” Dr. Vincent tells me. “However, chromium supplementation will not be a replacement for current therapies. Curiously, one notable recent result from rat studies indicates that pharmacological doses of chromium (not dietary or nutritional supplement, but significantly larger) may have an effect on insulin sensitivity. The results come from a study in Dr. Cefalu’s lab and two studies from my lab.”

In fact, if you have diabetes and take enough chromium chloride for long enough, it could do some good. And there is no reason to believe that the chromium chloride form would do harm. 

The most comprehensive review of chromium research is a 26-page article by John B. Vincent, “The bioinorganic chemistry of chromium(III)” in Polyhedron, 20 (2001) 1-26. The abstract is online on this page.

Other important articles by Dr. Vincent and others include:

Except for studies showing that chromium picolinate is a mutagen (see the PNAS study above), lay publications have not picked up on Dr. Vincent’s research to any great degree. In fact, a diligent search of the Web turned up only one mention:

“Herbs & Supplements: Chromium,” in The Natural Pharmacist online at


    There is no evidence that high-dose chromium treatment is effective in obese Western patients with type 2 diabetes. This is the conclusion of a new randomized, double-blind, placebo-controlled trial. The study, “Chromium Treatment Has No Effect in Patients With Poorly Controlled, Insulin-Treated Type 2 Diabetes in an Obese Western Population” appears in the March 2006 issue of Diabetes Care. A full-text version of the article is online.

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