Chromium is a trace mineral which is required in very small quantities by the human body. The exact function of chromium is still not very clear, though it is considered an essential mineral in human nutrition. The biologically active form which is utilized by the human body is trivalent chromium. Chromium is present in most of the body tissues, but most of it is found in the liver, kidneys and spleen.
The main function of chromium seems to be the regulation of blood glucose levels. Chromium functions as Glucose Tolerance Factor (GTF) along with some amino acids. The GTF stimulates insulin activity, which causes uptake of sugar from the blood into the cells, thereby maintaining normal blood sugar levels. During chromium deficiency, the function of insulin is compromised, leading to insulin resistance, which is a precursor for diabetes.
Chromium plays an important role in fat metabolism. It not only maintains cholesterol levels, but also maintains a proper ratio between High Density Lipoproteins (‘good’ cholesterol) and Low Density Lipoproteins (‘bad’ cholesterol). Thus, chromium is an important contributor in maintaining cardiovascular health.
Other functions of chromium include an increase in the lean body muscle mass, stimulation of certain enzymes and promoting the utilization of fats to be used as fuel, thus maintaining body weight.
Chromium is found in a wide variety of foodstuffs. However, the amount of chromium per serving of food is very low. Brewer’s yeast is an excellent source of chromium, though its consumption may not be very high in the diet. Whole grains are also a very good source of chromium. Processing procedures like milling and refining whole grains leads to considerable loss of this essential mineral.
There is not enough data on chromium to establish the Recommended Dietary Allowances (RDA). The Institute of Medicine at the National Academy of Sciences has set the Adequate Intake (AI) levels for chromium. These values, on a daily basis are as follows:
- 0-6 months: 0.2 micrograms
- 7-12 months: 5.5 micrograms
- 1-3 years: 11 micrograms
- 4-8 years: 15 micrograms
- Boys 9-13 years: 25 micrograms
- Girls 9-13 years: 21 micrograms
- Boys 14-18 years: 35 micrograms
- Girls 14-18 years: 24 micrograms
- Men 19-50 years: 35 micrograms
- Women 19-50 years: 25 micrograms
- Men 51 years and above: 30 micrograms
- Women 51 years and above: 20 micrograms
- Pregnant women 14-18 years: 29 micrograms
- Pregnant women 19-50 years: 30 micrograms
- Lactating women 14-18 years: 44 micrograms
- Lactating women 19-50 years: 45 micrograms
Chromium deficiency has been observed in humans. Too much consumption of processed and refined foods also increases the risk of chromium deficiency. Since chromium enhances insulin action, its deficiency will lead to impaired glucose tolerance. This can, however, proceed to develop into diabetes and exhibit symptoms of the same. Symptoms of chromium deficiency include fatigue and tiredness, mood swings, change in cholesterol levels, high triglyceride levels and obesity. All these changes in fat metabolism increase the risk for heart disease.
Chromium has a low absorption and high excretion rate. Hence, chromium toxicity is rare, either with dietary or supplemental chromium. However, there have been reports of toxicity in isolated cases. The symptoms include low blood sugar, as chromium increases the effectiveness of insulin, which in turn, promotes sugar uptake by the cells. Liver and kidney can also get damaged with a high intake, especially in people with preexisting kidney and liver disease.