Chromium (Cr) is an essential trace element for humans.
Chromium exists in nature in oxidation states ranging from Cr0 to Cr+6. The predominant forms are Cr+3 and Cr+6 (trivalent and hexavalent, respectively). Cr+6 is a strong oxidizing agent that is readily reduced to Cr+3 under acidic conditions such as the stomach. Cr+3 has a wide range of safety, while Cr+6 and Cr+4 have significant potential for toxicity.
Chromium absorption and utilization are influenced by other dietary factors such as chelating agents and conditions such as age and diabetes. Phytate, oxalate, and ascorbate promote Cr absorption.
Chromium absorption is generally low, approximately 0.4 – 2.0%. The percentage of dietary Cr absorbed decreases as the amount consumed increases. Excretion occurs through the kidney, with small amounts lost in hair, sweat and bile.
Chromium is distributed throughout the body, although studies and evidence regarding distribution are limited.
Research has shown Cr+3 to potentiate insulin action.
Cr+3 may stabilize nucleic acids (mainly RNA) against structural distortions.
Cr+3 may stimulate synthesis of fatty acids and cholesterol in the liver.
Glucose tolerance factor (GTF) contains Cr3+ and works like a hormone, along with insulin, to facilitate glucose transport from blood into the cells of various tissues. GTF also enhances intracellular metabolism of nutrients. In vitro studies found that GTF binds insulin-activated insulin receptors, stimulates tyrosine kinase activity and potentiates the activity of insulin
Supplementation of chromium and other nutrients often improves blood-sugar control in diabetic patients. In such cases, the dose of insulin or other antihyperglycemic agents may need to be reduced in order to avoid a hypoglycemic reaction. Consult with the prescribing physician before making dietary changes or taking nutrients.
Calcium carbonate and antacids tend to decrease the absorption of chromium. It is advisable to take chromium supplements 2 hours before or 4 hours after taking medications or other supplements.
Information on the relationship between substances and disease is provided for general information, in order to convey a balanced review of the scientific literature. In many cases the relationship between a substance and a disease is tentative and additional research is needed to confirm such a relationship.
Effects of chromium picolinate supplementation on body composition, strength, and urinary chromium loss in football players.
The effect of chromium picolinate supplementation on body composition, strength, and urinary chromium loss was investigated. Thirty-eight football players were randomly assigned in a double-blind format to receive either 200 mcg chromium picolinate or a placebo for nine weeks during spring training. Participants receiving chromium supplements had significant increases in urinary chromium excretion. No changes in body composition or strength were found. The results of this study agree with previous investigations of the effects of chromium on body composition.10
Chromium supplementation for women with gestational diabetes mellitus.
Researchers at Sonsum Medical Research Institute studied the effects of chromium supplementation on gestational diabetes. Thirty women participated in the 8 week study; 10 received 2 mcg Cr picolinate/kg body weight/day, 10 received a placebo, and 10 received 8 mcg Cr picolinate/kg body weight/day. Their results showed that 2 - 8 mcg/kg/body weight/day of Cr picolinate improved postprandial glucose concentrations and reduced hyperinsulinemia in women with gestational diabetes.11
Topic: Type 2 diabetes
Chromium treatment has no effect in patients with poorly controlled, insulin-treated type 2 diabetes in an obese Western population: a randomized, double-blind, placebo-controlled trial.
A 6-month randomized, double-blind, placebo-controlled trial investigated the effect of chromium supplementation in 46 obese people with poorly controlled type 2 diabetes. Subjects selected for the study had elevated HbA1c levels and required 50 units of insulin per day. Participants were randomized to receive 500 mcg chromium picolinate, 1000 mcg chromium picolinate, or a placebo daily. At the end of the trial, the reduction in HbA1c concentrations was approximately 0.4% in all groups. There was, however, a weak association between serum chromium concentration and improved lipid profile. This study did not find evidence to support a beneficial effect of chromium supplementation for obese people with poorly controlled type 2 diabetes. 3
Effects of acute chromium supplementation on postprandial metabolism in healthy young men.
Chromium supplementation potentiates the activity of insulin and can improve glucose tolerance. To investigate the possible glycemic index lowering effects of chromium, a randomized crossover design study was undertaken. Thirteen healthy young men participated in the three test meals (containing 75 g available carbohydrate with 400 mcg Cr picolinate, 800 mcg Cr picolinate, or placebo), with one week washout periods between each trial. Chromium supplementation (400 or 800 mcg) reduced capillary glucose by 23% and 20%, respectively, compared to carbohydrate alone. Interestingly, the trial revealed the presence of responders (10 subjects) who had significantly different glucose levels after chromium supplementation and nonresponders (3 subjects) who demonstrated no significant differences with supplementation. For the responders, capillary glucose was reduced by 36% and 30%, respectively, after supplementation with 400 or 800 mcg chromium. This study demonstrated that acute chromium supplementation could alter postprandial glucose metabolism for responders.17
The influence of chromium chloride-containing milk to glycemic control of patients with type 2 diabetes mellitus: a randomized, double-blind, placebo-controlled trial.
A recent randomized, double-blind, placebo-controlled study investigated the effects of chromium chloride supplemented milk on glycemic control in type 2 diabetes. Sixty people with type 2 diabetes, aged 30 to 75 years, were randomly assigned to receive either chromium supplemented milk (200 mcg chromium/20 g milk powder) or placebo twice daily for 16 weeks. The chromium supplemented group had lower fasting plasma glucose, fasting insulin, and improved metabolic control, especially in male patients. The data indicate that chromium supplementation may be useful for people with type 2 diabetes.16
Chromium supplementation does not improve glucose tolerance, insulin sensitivity, or lipid profile: a randomized, placebo-controlled, double-blind trial of supplementation in subjects with impaired gl
Forty people with impaired glucose tolerance (IGT) enrolled in a study to investigate the effects of chromium on glucose tolerance, insulin sensitivity, and lipid profiles. Half received 800 mcg/day of chromium picolinate for three months and the other half received a placebo. After three months, no significant benefits from supplementation were evident. Two statistically significant changes were noted during the study: an increase in serum chromium concentration in the supplemented group and a slight, but significant, increase in total cholesterol in the placebo group. This small study found no benefit from chromium picolinate supplementation.14
Elevated intakes of supplemental chromium improve glucose and insulin variables in individuals with type 2 diabetes.
A double-blind, placebo-controlled study of 180 people with type 2 diabetes was conducted to determine whether chromium supplementation plays a role in glycemic control. High doses of chromium (1000 mcg/day) significantly improved glycemic control as compared to placebo. Plasma total cholesterol concentration decreased in subjects consuming 1000 mcg of chromium per day after 4 months. Low doses of chromium (200 mcg/day) decreased fasting insulin, 2-hour insulin values and hemoglobin HbA1c, but did not lower plasma cholesterol concentration. 12
Low toenail chromium concentration and increased risk of nonfatal myocardial infarction.
In eight European countries and Israel, a study was conducted with men after diagnosis of first myocardial infarction (684 cases versus 724 controls) to evaluate the effect of chromium status on risk of myocardial infarction. Chromium status was determined from chromium content of toenails by neutron activation analysis. Average chromium concentrations were 1.10 mcg/g for cases and 1.30 mcg/g for controls. The relative risk of myocardial infarction was 0.82 for the second quintile and 0.59 for the highest quintile. There was an inverse association between toenail chromium concentration and risk of myocardial infarction. More trials are necessary to further investigate this association.13
Chromium picolinate improves insulin sensitivity in obese subjects with polycystic ovary syndrome.
A small study investigated the effect of 1000 mcg chromium picolinate daily on glucose disposal rate. Five obese women with polycystic ovary syndrome participated in the study. Supplementation with daily chromium resulted in a mean 38% reduction in glucose disposal rate. The authors concluded that chromium supplements may be useful insulin sensitizers for treatment of polycystic ovary syndrome. Larger studies are required to further investigate this result.15
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