A recent study published in the Journal of Biological Inorganic Chemistry (DOI: 10.1007/s00775-010-0734-y) found that rats supplemented with chromium equivalent to a human taking a standard nutritional supplement experienced no health benefits compared to rats fed a minimal amount of the mineral.
In the U.S. Department of Agriculture-funded study, researchers from the University of Alabama fed one group of rats a purified diet containing as little chromium (III) as practically possible for six months, closely monitoring their health through various measurements including blood tests. Other rats were given varying amounts of chromium in their diets while their health was monitored. Dr. John Vincent, professor of chemistry at University of Alabama and a co-author of the study, stated: “The diet that had as little chromium (III) as we could put in it and the diet that had an amount corresponding to a human taking a standard nutritional supplement with chromium had no effect on the rats. They had the same body mass (BMI), they ate the same amount of food, and they were able to metabolize glucose exactly the same. There were no differences in the health of the rats.” However, Vincent noted that when extremely high doses of chromium were used, the rats showed increased sensitivity to insulin, meaning their bodies did not have to produce as much insulin to metabolize excess sugar. He said: “If you have altered abilities to metabolize lipids and carbohydrates and you take an extremely large dose of chromium, it can lead to improvements at least based on the findings obtained from the animal models.” Vincent also challenged chromium’s status as an essential element, despite its acceptance as such by the National Academies of Sciences in 1980. He stated: “This means that the status of chromium in numerous nutrition and related textbooks and in the dietary guidelines of the national academies and USDA (and similar agencies) will need to be rewritten.” He explained the criteria for essential elements: “To be an essential element, you must show that if you take it out of the diet, the subject has adverse health effects; and if you restore it, those effects are reversed. Or, you need to show that it binds to a specific molecule in the body that has a specific function. The latter has not been done so the findings had previously relied on the nutritional studies.”
