Chromium, one of the most common elements in the earth’s crust and seawater, exists in our environment in several oxidation states, principally as metallic (Cr⁰), trivalent (+3), and hexavalent (+6) chromium. The average adult human body contains between 0.4 and 0.6 mg of chromium, while older people have a lower amount of microelements. The amount of chromium in the body depends on the environment in which one lives (and the latitude where he lives). Many studies show that the number of people suffering from diabetes and heart disease is lower in areas where it brings greater quantity in chrome. According to Di Bona et al. (2011), the chromium content of the diet had no effect on glucose levels in glucose tolerance or insulin tolerance tests.

Physiological role

Chromium has a functional role in glucose metabolism by increasing insulin action by its better binding, to the insulin receptors on target cells. In its trivalent form of chromium (Cr³⁺) may improve glucose tolerance in people who are capable of protein-calorie malnutrition. Hexavalent chromium (Cr⁶⁺) is a heavy metal used in a variety of industrial applications which is highly toxic to humans, animals, plants and microorganisms.

Trivalent chromium (Cr³⁺) is involved in the regulation of carbohydrate, lipid, and protein metabolism via an enhancement of insulin action. Chromium is a component of glucose tolerance factor, which works together with insulin, transporting glucose through the cell membrane into the cell. Glucose is used as an energy source. If sufficient quantities of chromium is consumed it leads to reduced need for insulin.

Insulin also plays an important role in the metabolism of fats and proteins, so that the chromium is necessary for the normal functioning of these processes. Adequate intake of chromium is essential for the maintenance of adequate levels of cholesterol and an important role in weight loss.

It is believed that chromium also plays an important role in metabolism of plasma lipoproteins.

Metabolism

Chromium is absorbed from the small intestine. It is transmitted to the tissue attached to transferrin and it appears in mitochondria, microsomes and liver cytosol. Chromium is excreted primarily in the urine.

Absorption of chromium from food is relatively low - only 2-10% chromium ingested with food is absorbed. Organic chromium is absorbed better than inorganic. Absorption of chromium is increased in the presence of oxalate and in the cases of iron deficiency. Absorption also decreases with age.

Food sources of chromium

Trivalent chromium is found in a wide range of foods, including egg yolks, whole-grain products, high-bran breakfast cereals, coffee, nuts, green beans, broccoli, meat, brewer’s yeast, and some brands of wine and beer. The amount of chromium in food varies by location from which the food originates.

When preparing food can easily result in the loss of chromium, it is therefore recommended that food, if possible, is consumed in the fresh form. An additional source of chromium may be storing food in containers made of stainless steel when preparing acidic foods.

Chromium content in food products

Recommended daily allowance

There is no recommended daily allowance of chromium intake because it is hard to determine the percentage of chromium and there are no adequate tests to determine it. It is also obsolete that the chromium is stored in the tissues while also quickly removed from the blood serum at the same time. It is estimated that health is not affected adversely if the entries is from 50-200 µg per day.

Deficiency

Symptoms of chromium deficiency are high levels of fat and cholesterol in the blood, as well as symptoms that resemble to diabetes such as glucose intolerance, body weakness, depression, weight loss, thirst and hunger, frequent urination.

Industrial refined and processed foods, such as flour and sugar cane in some cases (alcoholism, long-term diets, pregnancy) cause loss of chromium from the body.

Infections and physical traumas increase the daily intake of chromium, and strenuous exercise increase the excretion of chromium which may increase the possibility of a lack of chromium in the body.

The level of chromium in the tissues decreases with age. British researchers analyzed the levels of chromium in the hair, sweat and serum samples of over 40,000 patients in a study published in 1997. The results showed that a significant reduction of chromium occurs with age, which leads to an increased risk of diabetes and atherosclerosis in the elderly.

The lack of chromium is relatively common in people with diabetes type II and may impair the function of glucose tolerance factor - GTF. This leads to poor absorption of glucose in the cells.

Inadequate chromium metabolism plays an important role in diabetes in pregnant women.

High levels of insulin also increase the excretion of chromium. Lack of chromium leads to hypoglycaemia or low blood sugar levels.

Lack of chromium plays important role in heart disease. Low levels of chromium in food intake are associated with higher levels of cholesterol, which increases the risk of atherosclerosis. Patients with heart disease at an advanced stage usually have lower levels of chromium in the blood.

Overdose

Little is known about the toxic effects of large amounts of chromium in food and feed additives. It is shown that the consuming more than 250 mg leads to an irregular heart beat.

Hexavalent chromium (Cr⁶⁺) is much more toxic than trivalent chromium (Cr³⁺). Chronic exposure to chrome dust appears to be the risk for lung cancer improvement. Significant amounts of chromium can enter the body by cooking in vessels made of stainless steel.

It has shown that enrichment of food with chromium can cause serious damage to chromosomes. It is believed that excess chromium intake plays an important role in carcinogenesis.

Severe auditory and optic nerve toxicity has also been observed, in patients exposed to an abnormal release of cobalt and chromium from damaged hip prostheses.

Chromium in medicine

Diabetes: Chromium is successfully used in diabetes type I and type II, in the pregnancy and in hypoglycemia. Adding chromium enable higher tolerance to glucose. This affects the maintenance of blood glucose levels stable and protect blood vessels and organs of damage caused by high glucose levels. Chromium reduces fat levels in the blood of diabetics with type II diabetes.

Hypercholesterolaemia: Chromium can reduce the level of total and LDL (low density lipoprotein) and increases levels of beneficial HDL (high density lipoproteins). Hence the chromium can also be used to treat certain heart diseases.

Weight loss: Some scientists believe that consuming moderate amounts of chromium in the form of chromium picolinate may contribute to weight loss, reduce fat and increase muscle mass.

References

Apostoli P., et al., 2013, “High doses of cobalt induce optic and auditory neuropathy,” Experimental and Toxicologic Pathology; 65(6): 719-727. [Web Reference]

Cefalu W.T. and Hu F.B., 2004, “Role of chromium in human health and in diabetes,” Diabetes Care; 27(11): 2741-2751. [Web Reference]

Di Bona K.R., et al., 2011, “Chromium is not an essential trace element for mammals: effects of a “low-chromium” diet,” JBIC Journal of Biological Inorganic Chemistry; 16(3): 381-390. [Web Reference]

Doisy R.J., et al., 2013, “Chromium metabolism in man and biochemical effects,” Trace Elements in Human Health and Disease; 2: 79-104. [Web Reference]

Institute of Medicine (US) Panel on Micronutrients. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington (DC): National Academies Press (US); 2001. 6, Chromium. [Web Reference]

Laschinsky N., et al., “Bioavailability of chromium (III)-supplements in rats and humans,” Biometals; 25(5): 1051-1060. [Web Reference]

Soetan K.O., Olaiya C. O. and Oyewole O.E., 2010, “The importance of mineral elements for humans, domestic animals and plants-A review,” African Journal of Food Science; 4(5): 200-222. [Web Reference]