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).
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% of the U.S. population being 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. 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.
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 found in such small concentrations, this mineral is important to health. There are about 6mg 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
. 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.
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.
Incidence; Causes and Development
Deficiencies are more common in both the elderly and the young, especially teenagers on poor diets.
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 rose more than sixfold during the second half of the 20th century. This increase may also 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% loss) and white sugar (93% 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
disease, our number one killer.
People who eat a diet high in sugar and refined foods are more at risk for not getting enough chromium. Sugar increases chromium loss and refined foods are very low in chromium. Athletes may also have increased chromium loss through exercise.
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.
Signs and Symptoms
Even mild deficiencies of chromium
can produce symptoms other than problems in blood sugar metabolism, such as anxiety
. 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.
Chromium deficiency can resemble diabetes
Treatment and Prevention
There is no specific RDA for chromium
. Average daily intake may be about 80-100mcg. We probably need a minimum of 1-2mcg going into the blood to maintain tissue levels; since only around 2% of our intake is absorbed, we need at least 100-200mcg in the daily diet. A safe dosage range for chromium supplementation is 200-300mcg. Children need somewhat less. Many vitamin or mineral supplements contain about 100-150mcg of chromium. Some people take up to 1mg (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 50mcg, since it is thought to be better absorbed with niacin
and the amino acids glycine
and glutamic acid
To Avoid Deficiency and Maintain a Good Intake of Chromium:
- Avoid sugar and sugar products, soda pops, candy, and presweetened breakfast cereals.
- Avoid refined, white flour products, such as white breads and crackers.
- Use whole wheat products, wheat germ, and/or brewer's yeast.
- Eat whole foods.
- Take a general supplement that contains chromium, approximately 100-200mcg daily.