Chromium is an essential trace element that is most well known for its role in insulin function and cellular glucose uptake. Lack of trivalent chromium (Cr3+) in the diet results in insulin resistance, diabetes and ultimately death due to a failure of normal carbohydrate metabolism. Through its effects on insulin chromium is able to effect lean body mass. Chromium is also required for regulation of corticosteroid metabolism, may alter bone density and protect from dementias in the elderly. Chromium deficiencies are common in Western populations because of the low levels of chromium found in commonly eaten foods and the fact that high sugar diets deplete the body of its chromium stores. Chromium status is known to decline with age, partly because of decreasing absorption rates as well as changes the dietary patterns.
Chromium deficiency results in insulin resistance because chromium is necessary for the binding of insulin to its receptors. Cells have receptors for insulin, with binding being necessary for glucose uptake from the blood. When insulin binds to the receptor it activates glucose uptake, thus lowering blood glucose levels. However, this process also requires chromium. In response to rising blood sugar levels, chromium leaves the blood and enters the insulin sensitive cells where it forms a complex called chromodulin, Chromodulin binds to the insulin receptor and allows it to be activated by insulin. After the insulin has bound to the receptor and facilitated glucose entry, the chromium unbinds from the insulin receptor and is excreted from the cell and lost to the urine. High sugar diets deplete chromium because they increase the binding rate of chromodulin and the subsequent excretion of chromium.
Research published in the British Journal of Nutrition in 20071 investigated the chromium content of French food eaten by elderly French free living subjects. The results showed that despite generally well balanced diets, the chromium levels in the food was very low, with more than 90% of the self selected foods resulting in subjects not reaching the French RDA for chromium (60 µg/d). These results support previous that recorded low levels of chromium in American and European diets. For example, in the US chromium intakes in the elderly were 25 to 37 µg/d and were even lower in younger US subjects. In Switzerland, Finland and Sweden the intakes of chromium were all 50 µg/d or less. In Belgium the intakes of chromium were recorded at 53 µg/d and in Poland and Germany the intakes of chromium have been recorded at 60-90 µg/d.
These results are consistent with research that suggests that mineral deficiencies are becoming more common due to intensive farming techniques, as well an over reliance on diets containing processed nutritionally poor foods. Although the RDA for chromium was designed to ensure adequate chromium intake by the majority of the population, in reality the RDA is likely set too low as government recommendations tend to err on the side of caution and safety. The RDA also does not take into account those with higher requirements, such as athletes, those under stress or those with high sugar intakes. Chromium in its trivalent form has an exceptional safety record and is very cheap. Studies with athletes suggest that 200 to 800 µg/d may enhance lean body tissue and improve weight loss via improved insulin sensitivity. However, to attain these levels supplementation is required using an absorbable form such as chromium picolinate or GTF chromium.
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1Roussel, A., Andriollo-Sanchez, M., Ferry, M., Bryden, N. A. and Anderson, R. A. 2007. Food chromium content, chromium intake and related biological variables in French free-living elderly. British Journal of Nutrition. 98: 326-331
