Chromium has become a subject of much interest in recent years, and we continue to learn more about it. Chromium was long thought to be a toxic mineral until it was discovered in 1957 to be the essential part of glucose tolerance factor (GTF). GTF (and thus chromium) is a vital molecule in regulating carbohydrate metabolism by enhancing insulin function for proper use of glucose in the body. GTF is composed of one chromium molecule in the trivalent state (a +3 charge), two niacin molecules, and three amino acids-glycine, cysteine, and glutamic acid.
Trivalent chromium is the biologically active form. Hexavalent chromium (+6) is fairly unstable and is potentially toxic in the body. Chromium is not found in nature as a free metal, so it must be reduced to its elemental form to make the "chrome" used in the auto industry. This form, however, is not available to the body, so we cannot meet our daily chromium needs by sucking on car bumpers. The chromium in the blood is in the organic active form in the trivalent state, as part of GTF or carried with a beta-globulin protein.
Chromium is really considered an "ultra-trace" mineral, since it is needed in such small quantities to perform its essential functions. The blood contains about 20 parts per billion (ppb), a fraction of a microgram. Even though it is in such small concentrations, this mineral is important to health. There are about 6 mg. of chromium stored in the bodies of people who live in the United States; tissue levels of people in other countries are usually higher, and those higher levels tend to be associated with a lower incidence of diabetes and atherosclerosis. There is less hardening of the arteries in people of Asian countries, who it is estimated have five times higher chromium tissue levels than Americans. People of Near Eastern countries who have about four times the average U.S. levels and African people who have twice our chromium levels seem to experience less diabetes than Americans. These higher tissue levels of chromium are due primarily to better soil supplies and a less refined diet. Chromium may be only one of the factors accounting for the differences in rates of diabetes and atherosclerosis between cultures, but it is probably a major one.
Chromium is a difficult mineral to absorb. Figures range from 0.5-3 percent absorption for the inorganic chromium salts often found in food. The organic complexes of chromium, such as GTF, are absorbed better, at about 10-20 percent. The kidneys clear any excess from the blood, while much of chromium intake is eliminated through the feces. This mineral is stored in many parts of the body, including the skin, fat, brain, muscles, spleen, kidneys, and testes.
Tissue levels of chromium tend to decrease with age, which may be a factor in the increase of adult-onset diabetes, a disease whose incidence has risen more than sixfold in the past 50 years. This increase may mirror the loss of chromium from our diets because of soil deficiency and the refinement of foods. Much of the chromium in whole grains and sugarcane is lost in making refined flour (40 percent loss) and white sugar (93 percent loss). In addition, there is some evidence that refined flour and sugar deplete even more chromium from the body. Reduced absorption related to aging, diets that are stressful to the digestive system, and the modern refined diet all contribute to chromium deficiency. Higher fat intake also may inhibit chromium absorption. If chromium is as important as we think it is to blood sugar metabolism, its deficiency may be in part responsible, along with the refined and processed diet, for the third leading cause of death (more than 300,000 yearly) in this country, diabetes mellitus, and this figure does not reflect other deaths that may be related to chromium deficiency, since high blood sugar levels seen in diabetes also increase the progression of atherosclerosis and cardiovascular disease, our number one killer. Diagnosing and treating chromium deficiency is simple and should be done as early as possible, as it is much easier to prevent diabetes than to treat it.