Chromium (Cr): Food Sources, RDA, Deficiency, Toxicity
What is Chromium
Chromium is an essential trace element that plays an important role in various body functions. In particular, chromium forms a complex in the body that enhances the action of insulin, thereby reducing blood glucose levels. However, it also has some risks and its use is controversial.
Health Benefits
Chromium has attracted the interest of scientists for its potential benefits in some health problems.
Chromium is used as a dietary supplement to treat diabetes, lower blood lipid levels and weight loss.
Type 2 diabetes
In type 2 diabetes the pancreas usually produces enough insulin, but for unknown reasons, the body cannot use insulin effectively. The disease occurs because muscle cells and other tissues become resistant to insulin, especially in obese people.
Insulin allows glucose to enter most cells, where glucose is converted into energy, stored in the liver and muscles (as glycogen) and converted into fat when in excess. Insulin resistance leads to higher than normal blood glucose levels (hyperglycaemia).
Chromium deficiency interferes with the body’s ability to use glucose to meet our energy needs and increases insulin requirements. Many studies have shown that chromium supplements help control type 2 diabetes and insulin response in people who are at high risk of developing the disease.
Of course, the use of chromium supplements for diabetes is controversial. More scientific data are needed to prove that it is effective in treating diabetes.
Cholesterol
The effects of chromium on blood lipids are also controversial. Some studies show that chromium supplements can lower LDL cholesterol (bad cholesterol) and triglyceride levels and increase the concentration of apolipoprotein A (HDL or good cholesterol) in patients with atherosclerosis or elevated cholesterol levels.
Body weight
Chromium supplements several times claim to reduce fat and increase muscle mass. Some studies have shown that chromium supplements help weight loss compared to people taking no supplement, but the changes seen are very small and questionable in terms of clinical significance. More research is needed to better understand the mechanism of action of chromium.
Chromium Food Sources
The exact chromium content of food is difficult to determine, mainly due to differences in soil’s mineral content.
☝ The processing of grains and the removal of the germ reduces the chromium content.
Recommended Daily Allowance (RDA)
The daily dose of chromium ranges from 50 to 200μg per day for adults and adolescents.
How is chromium absorbed?
The absorption of chromium by the body occurs mainly in the duodenum (the first part of the small intestine and depends on the form in which the chromium is found, i.e. whether it is inorganic or organic.
The absorption of inorganic chromium is very low and ranges between 0.4-2%. The biologically organic complex of chromium, known as the glucose tolerance factor, is absorbed to a greater extent, between 10-25%.
In the blood, the inorganic form is bound to transferrin and transported with iron. Also albumin (a protein made by the liver) is involved in the transport of chromium.
The inorganic form is not active so it is transported mainly in the liver, where it can be converted to the active organic form.
☝ Chromium-rich tissues are the kidneys, liver, muscles, spleen, heart and pancreas.
What is the biological role of chromium?
The biological role of chromium is due to its contribution to the creation of the glucose tolerance factor.
The action of insulin is more effective in the presence of chromium. The primary role of glucose tolerance factor is to enhance the action of insulin, increasing insulin uptake by cells and affecting carbohydrate and lipid metabolism.
Some studies have shown that chromium supplementation may improve the lipid profile by increasing the levels of good cholesterol (HDL) and decreasing bad cholesterol (LDL).
Chromium also appears to be involved in nucleic acid metabolism and in the regulation of gene expression.
Read Also: 10 Foods That Lower Cholesterol and 10 that Cause Plaque Build Up
Interactions with other nutrients
The following food components have been found to inhibit chromium absorption:
What causes chromium deficiency?
Chromium deficiency was reported in three patients with long-term intravenous feeding whose intravenous solutions were not supplemented with chromium.
These patients developed evidence of non-normal glucose utilization and increased their insulin requirements for chromium supplementation.
In addition, impaired glucose tolerance in malnourished infants was combated with an oral dose of chromium chloride.
Several studies of male runners have shown that urinary chromium loss increased with endurance exercise, suggesting that chromium needs may be greater in individuals who exercise regularly.
In a more recent study, dynamic exercise (weightlifting) was found to increase urinary chromium excretion in the elderly. However, chromium absorption also increased, resulting in little or no net loss of chromium as a result of dynamic exercise.
Currently, research on the effects of inadequate chromium intake and risk factors for chromium deficiency is limited by the lack of sensitive and accurate tests to determine the nutritional value of chromium.
Chromium requirements may be increased in patients with diabetes and cardiovascular disease. Chromium deficiency leads to insulin resistance and hyperinsulinemia.
Also mild chromium deficiency can be a risk factor for a number of symptoms similar to Metabolic Syndrome, which can lead to cardiovascular disease.
Also trauma and stress increase chromium requirements due to increased glucose metabolism.
Toxicity from chromium
Hexavalent chromium or chromium (VI) is a recognized carcinogen. Exposure to chromium (VI) in powder form is associated with the increasing incidence of lung cancer and is known to cause skin irritation (dermatitis).
In contrast, there is little evidence that trivalent chromium or chromium (III) is toxic to humans.
No adverse effect has been conclusively linked to excessive intake of chromium (III) from food or dietary supplements.
Most of the concerns about the long-term safety of chromium (III) supplementation arise from several studies in cell culture, noting that chromium (III) can increase DNA damage.
At present, there is no evidence that chromium (III) increases DNA damage in living organisms.
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