Henry Schroeder, M.D., who has done numerous studies with chromium, has shown that 2 mg. of inorganic chromium given daily reduced cholesterol levels by about 15 percent. He has produced diabetes in lab animals by feeding them chromium-deficient diets. Such a diet raises not only blood sugar but blood cholesterol as well; both conditions return to normal with chromium supplementation. When Dr. Schroeder fed rats a chromium-rich diet, they showed improved longevity along with a reduction of atherosclerotic plaque found in the blood vessels at death. Chromium is used to help reduce atherosclerosis in people, especially in those who show low chromium levels. Cultures with higher tissue levels of chromium also appear to have lower incidences of atherosclerosis and heart disease.
Deficiency and toxicity: Because of the low absorption and high excretion rates of chromium, toxicity is not at all common in humans, especially with the usual forms of chromium used for supplementation. The amount of chromium that would cause toxicity is estimated to be much more than the amount commonly supplied in supplements.
Chromium deficiency is another story, however, with an estimated 25-50 percent of the U.S. population deficient in chromium. The United States has a greater incidence of deficiency than any other country, because of very low soil levels of chromium and the loss of this mineral from refined foods, especially sugar and flours. Deficiencies are more common in both the elderly and the young, especially teenagers on poor diets. Even though chromium is needed in such small amounts, it is difficult to obtain. Given these factors, and the fact that the already-low chromium absorption rate decreases even further with age, chromium deficiency is of great concern. It may even be the missing link in the development of adult-onset diabetes, a serious problem increasing rapidly in our culture. Nearly one in five adult Americans now develops diabetes.
A high-fat, high-sugar diet that contains refined flour products is probably the most important risk factor for diabetes. Such a diet tends to be low in chromium content and also causes more insulin to be produced, which requires even more chromium. Milk and other high-phosphorus foods tend to bind with chromium in the gut to make chromium phosphates that travel through the intestines and are not absorbed.
Even mild deficiencies of chromium can produce symptoms other than problems in blood sugar metabolism, such as anxiety or fatigue. Abnormal cholesterol metabolism and increased progress of atherosclerosis are associated with chromium deficiency, and deficiency may also cause decreased growth in young people and slower healing time after injuries or surgery. Most important, the low chromium levels seen in the United States are associated with a higher incidence of diabetes and arteriosclerosis. Further research is needed to confirm these associations and to determine whether correcting the chromium deficiency would actually reduce the incidence of these diseases.
Requirements: There is no specific RDA for chromium. Average daily intake may be about 80-100 mcg. We probably need a minimum of 1-2 mcg. going into the blood to maintain tissue levels; since only around 2 percent of our intake is absorbed, we need at least 100-200 mcg. in the daily diet. A safe dosage range for chromium supplementation is between 200-300 mcg. Children need somewhat less. Many vitamin or mineral supplements contain about 100-150 mcg. of chromium. Some people take up to 1 mg. (1,000 mcg.) per day for short periods without problems; this is not suggested as a long-term regimen but rather to help replenish chromium stores when deficiency is present. All of the precursors to the active form of GTF are used in some formulas, but usually with chromium in lower doses, such as 50 mcg., since it is thought to be better absorbed with niacin and the amino acids glycine, cysteine and glutamic acid.