Chromium is an essential trace mineral.
In the UK, no Reference Nutrient Intake or Estimated Average Requirement has been set. A safe and adequate intake is, for adults, 50– 400 µg daily; for children and adolescents, 0.1– 1.0 µg/kg daily.
In the USA, the Adequate Intake (AI) for men (19–50 years) is 35 µg daily and for women (19– 50 years) is 25 µg daily. For those aged over 51, the AI is 30 µg daily for men and 20 µg daily for women.
In the UK, the average adult diet provides 13.6– 47.7 µg daily.
Chromium functions as an organic complex known as glucose tolerance factor (GTF), which is thought to be a complex of chromium, nicotinic acid and amino acids. It potentiates the action of insulin and thus influences carbohydrate, fat and protein metabolism. Chromium also appears to influence nucleic acid synthesis and to play a role in gene expression.
Wholegrain cereals (including bran cereals), brewer’s yeast, broccoli, processed meats and spices are the best sources. Dairy products and most fruits and vegetables are poor sources.
Chromium is poorly absorbed (0.5–2% of intake); absorption occurs in the small intestine by mechanisms that have not been clearly elucidated, but which appear to involve processes other than simple diffusion.
Chromium is transported in the serum or plasma bound to transferrin and albumin. It is widely distributed in the tissues.
Absorbed chromium is excreted mainly by the kidneys, with small amounts lost in hair, sweat and bile.
Absorption of chromium is increased by oxalate and by iron deficiency, and reduced by phytate. Diets high in simple sugars (glucose, fructose, sucrose) increase urinary chromium losses. Absorption is also increased in patients with diabetes mellitus, and depressed in the elderly. Stress and increased physical activity appear to increase urinary losses.
Gross chromium deficiency is rarely seen in humans, but signs and symptoms of marginal deficiency include: impaired glucose intolerance, fasting hyperglycaemia, raised circulating insulin levels, glycosuria, decreased insulin binding, reduced number of insulin receptors, elevated serum cholesterol, elevated serum triglycerides, and central and peripheral neuropathy.
Because of its effects on insulin, chromium has been investigated for a potential role in diabetes mellitus, and it has also been promoted for body building in athletes. It has also been investigated for a potential role in cholesterol lowering and reducing the risk of CVD.
Chromium deficiency may result in insulin resistance, although other researchers have concluded that low-chromium diets have no effect on either insulin or blood glucose. Chromium supplementation may improve glycaemic control in some patients with type 1 and 2 diabetes and gestational diabetes, but relatively high doses (e.g. 1000 µg daily) may be needed. Serum lipid fractions may also be reduced by chromium in patients with diabetes.
Chromium picolinate (200 µg three times a day) reduced glycosylated haemoglobin in a woman with type 1 diabetes mellitus, and the patient also reported improved blood glucose values. Chromium picolinate (200 µg daily) increased insulin sensitivity in patients with type 1 and type 2 diabetes, allowing for a reduction in dose of insulin or hypoglycaemic drugs without compromising glucose control. Steroid-induced diabetes was improved after supplementation with chromium 200 µg three times a day, and chromium 200 µg daily was sufficient to maintain normal blood glucose thereafter.
In a double-blind, placebo-controlled trial, 180 patients with type 2 diabetes were randomised to receive 250 µg chromium twice a day, 100 µg chromium twice a day, or placebo. After 2 months, glycosylated haemoglobin levels were significantly lower in the high-dose chromium group and after 4 months were lower in both chromium groups compared with placebo. Fasting and 2-hour insulin levels were significantly lower in both chromium groups at 2 and 4 months, but significantly lower glucose values and lower plasma cholesterol were found only in the high-dose chromium group.
In a prospective, double-blind, placebo-controlled, crossover study in 28 subjects with type 2 diabetes, serum triglycerides were significantly reduced by chromium (200 µg daily for 2 months). However, there was no change in fasting glucose, or plasma LDL or HDL levels.
In a double-blind, placebo-controlled, crossover study, 78 patients with type 2 diabetes in Saudi Arabia received in random order brewer’s yeast (23 µg chromium) and 200 µg chromium from chromium chloride for 4 weeks each. Mean HDL cholesterol and serum and urinary chromium were all raised by chromium intake. After each chromium phase, mean drug dosage tended to decrease, but was not significant except in the case of glibenclamide. There was no change in dietary intakes or body mass index. Overall, brewer’s yeast was associated with better chromium retention and more positive effects than chromium chloride.
Supplementation of nicotinic acid together with chromium may increase its effectiveness. In a study involving 16 healthy elderly volunteers, neither chromium 200 µg daily nor nicotinic acid 100 mg daily affected fasting glucose or glucose tolerance. However, chromium administered with nicotinic acid resulted in a 15% decrease in the area under the glucose curve and a 7% decrease in fasting glucose.
A systematic review and meta-analysis of 15 RCTs involving 618 participants, of whom 193 had type 2 diabetes and 425 were in good health or had impaired glucose tolerance, showed that there was no effect of chromium on glucose or insulin concentrations in non-diabetic subjects and the data for people with diabetes were inconclusive. Only one of the studies in the meta-analysis, involving 155 subjects in China, showed that chromium reduced glucose and insulin concentrations and HbA1c.
Further studies have investigated other potential effects of chromium in patients with diabetes. Chromium supplementation has been found to minimise increased oxidative stress in type 2 diabetes mellitus patients with high HbA1c levels. Chromium supplementation (400 or 800 µg) improved glucose tolerance in 10 out of 13 subjects in a randomised crossover study. Short-term chromium supplementation (1000 µg) has also been found to shorten QTc interval in patients with type 2 diabetes mellitus.
A US review concluded that there is little evidence that chromium has any value in glucose metabolism in those without type 2 diabetes, or on weight loss. The review also suggested that it may have a value in type 2 diabetes but this is still to be established. Another conclusion was that there is some evidence that chromium added to total parenteral nutrition (TPN) solutions may reduce the risk of hyperglycaemia in patients receiving this therapy.
In some controlled human studies, chromium has been reported to reduce body fat and increase fat-free mass, but to have no effect in others. A meta-analysis of 10 trials found that chromium picolinate had a favourable effect on body weight. However, sensitivity analysis suggested that this effect is largely dependent on the results of a single trial. The authors concluded that the effect of chromium is likely to be small and its clinical relevance debatable.
Chromium supplements are claimed to influence body composition during body-building programmes, although there is little evidence for this. In a study involving 36 men on a weight-training programme, chromium supplementation had no effect on strength, fat-free mass or muscle mass. Chromium picolinate (200 µg a day) did not alter body fat, lean body mass and skin-fold thickness in untrained young men on an exercise programme. Neither body composition nor strength changed as a result of chromium picolinate supplementation (200 µg daily) in football players during a 9-week training programme. Young women on a weight-training programme taking chromium picolinate (200 µg daily for 12 weeks) gained significantly more weight than those taking a placebo, and there was a non-significant increase in lean body mass. However, there were no effects on body composition or strength in the young men on the same programme. In moderately obese women placed on an exercise programme, 12 weeks of chromium supplementation (400 µg daily) did not significantly affect body composition, resting metabolic rate, plasma glucose, serum insulin, plasma glucagons, serum C-peptide and serum lipid concentrations.
Chromium supplements have been claimed to reduce serum cholesterol levels, and there is some evidence for this.
Two placebo-controlled trials, one in 76 men on beta-blockers (a double-blind study), the other in 76 patients with atherosclerosis (not blinded), showed a significant increase in serum HDL cholesterol with chromium (300 µg daily in the first study, 200 µg daily in the second). In a double-blind, placebo-controlled, crossover study in 28 healthy subjects, chromium supplementation (200 µg daily) resulted in a statistically significant reduction in total and LDL cholesterol. HDL was not raised significantly, although apolipo-protein A-1 (the principal protein in A-1) was increased.
Patients with depression may respond to chromium. In a double-blind RCT, 113 adults with atypical depression, most of whom were obese, were randomised to receive 600 µg of elemental chromium or placebo. Chromium produced an improvement in carbohydrate craving and appetite increase and diurnal variation in feelings. The results suggested that the main benefit of chromium was in depressed patients with high carbohydrate craving. The authors concluded that further research is needed in depressed patients specifically selected for symptoms of increased appetite and carbohydrate craving.
Chromium supplements containing yeast should be avoided by patients taking monoamine oxidase inhibitors. Patients with diabetes mellitus should not take chromium supplements unless medically supervised (chromium may potentiate insulin).
Pregnancy and breastfeeding
No problems reported at normal intakes.
Oral chromium, particularly trivalent chromium (the usual form in supplements), is relatively non-toxic and unlikely to induce adverse effects. However, in 2003, the report of the Expert Group on Vitamins and Minerals (EVM) noted that there was some evidence suggesting that chromium picolinate might be genotoxic (i.e. it could damage DNA). In the light of this, the Food Standards Agency advised that consumers who wished to take chromium supplements should use other types of supplements until specialist advice had been received from the Committee on Mutagenicity (COM). The COM reviewed the evidence and recommended more research. On the basis of this research the COM concluded that the balance of evidence suggested that chromium picolinate was not genotoxic.
Industrial exposure to high amounts of chromate dust is associated with an increased incidence of lung cancer and may cause allergic dermatitis and skin ulcers. The hexavalent form (not found in food or supplements) can cause renal and hepatic necrosis.
Insulin: may reduce insulin requirements in diabetes mellitus (monitor blood glucose). Oral hypoglycaemics: may potentiate effects of oral hypoglycaemics.
Chromium is available in the form of chromium picolinate, chromium nicotinic acid, chromium chloride or as an organic complex in brewer’s yeast. It is available in tablet and capsule form and is present in multivitamin/mineral preparations.
The dose is not established. Studies have been conducted with 200–500 µg elemental chromium daily. Dietary supplements provide, on average, 200 µg in a daily dose.
Preliminary evidence suggests that chromium may improve insulin resistance and glucose control in diabetes, although not all studies have reached this conclusion. Preliminary evidence also suggests that chromium may improve serum lipid levels. However, there is no good evidence that chromium reduces body weight or body fat. Despite claims made for chromium in sports, there is no evidence that it has body-building effects in athletes. Preliminary evidence suggests that chromium may be helpful in depression with carbohydrate craving.
Dietary Supplements, Third Edition, by Pamela Mason, BSc, MSc, PhD, MRPharmS, published by Pharmaceutical Press, London, 2007.
Mertz W. Chromium in human nutrition: a review. J Nutr 1993; 123: 626–633.
Anderson RA. Nutritional factors influencing the glucose/insulin system: chromium. J Am Coll Nutr 1997; 16: 404–410.
Fox GN, Sabovic Z. Chromium picolinate supple-mentation for diabetes mellitus. J Fam Pract 1998; 46: 83–86.
Ravina A, Slezak L, Rubal A. Clinical use of the trace element chromium(III) in the treatment of diabetes mellitus. J Trace Elem Exper Med 1995; 8:183–190.
Ravina A, Slezak L, Mirsky N. Reversal of corticosteroid-induced diabetes mellitus with supplemental chromium. Diabet Med 1999; 16: 164–167.
Anderson RA, Cheng N, Bryden NA. Elevated intakes of supplemental chromium improve glucose and insulin variables in individuals with type 2 diabetes. Diabetes 1997; 46: 1786–1791.
Lee NA, Reasner CA. Beneficial effect of chromium supplementation on serum triglyceride levels in NIDDM. Diabetes Care 1994; 17: 1449–1452.
Bahijiri SM, Mira SA, Mufti AM, et al. The effects of inorganic chromium and brewer’s yeast supplemen-tation on glucose tolerance, serum lipids, and drug dosage in individuals with type 2 diabetes. Saudi Med J 2000; 21: 831–837.
Urberg M, Zemel MB. Evidence for synergism between chromium and nicotinic acid in the control of glucose tolerance in elderly humans. Metabolism 1987; 36: 896–899.
Althuis MD, Jordan NE, Ludington EA, Wittes JT. Glucose and insulin responses to dietary chromium supplements: a meta-analysis. Am J Clin Nutr 2002; 76: 148–155.
Cheng HH, Lai MH, Hou WC, Huang CL. Anti-oxidant effects of chromium supplementation with type 2 diabetes mellitus and euglycemic subjects. J Agric Food Chem 2004; 52: 1385–1389.
Frauchiger MT, Wenk C, Colombani PC. Effects of acute chromium supplementation on postprandial metabolism in healthy young men. J Am Coll Nutr 2004; 23: 351–357.
Vrtovec M, Vrtovec B, Briski A, et al. Chromium supplementation shortens QTc interval duration in patients with type 2 diabetes mellitus. Am Heart J 2005; 149: 632–636.
Anonymous. Chromium supplements. Med Lett Drugs Ther 2006; 48: 7–8.
Kaats GR, Blum K, Fisher JA. Effects of chromium picolinate supplementation on body composition: a randomized, double-masked, placebo-controlled study. Curr Ther Res 1996; 57: 747–756.
Kaats GR, Blum K, Pullin D. A randomized double-masked, placebo-controlled study of the effects of chromium picolinate supplementation on body com-position: a replication and extension of a previous study. Curr Ther Res 1998; 59: 379–388.
Cefalu WT, Bell-Farrow AD, Wang ZQ. The effect of chromium supplementation on carbo-hydrate metabolism and body fat distribution. Diabetes 1997; 46 (Suppl. 1): 55A.
Trent LK, Thieding-Cancel D. Effects of chromium picolinate on body composition. J Sports Med Phys Fitness 1995; 35: 273–280.
Lukaski HC, Bolonchuk WW, Siders WA. Chromium supplementation and resistance training: effects on body composition, strength and trace element status of men. Am J Clin Nutr 1982; 35: 661–667.
Pittler MH, Stevinson C, Ernst E. Chromium picolinate for reducing body weight: meta-analysis of randomized trials. Int J Obes Relat Metab Disord 2003; 27: 522–529.
Hallmark MA, Reynolds TH, DeSouza TA. Effects of chromium and resistive training on muscle strength and body composition. Med Sci Sports Exerc 1996; 28: 139–144.
Clancy SP, Clarkson PM, DeCheke ME. Effects of chromium picolinate supplementation on body composition, strength and urinary chromium loss in football players. Int J Sports Nutr 1994; 4: 142–153.
Hasten DL, Rome EP, Franks BD. Effects of chromium picolinate on beginning weight training students. Int J Sports Nutr 1992; 2: 343–350.
Roeback JR, Hla KM, Chambless LE, et al. Effects of chromium supplementation on serum high density lipoprotein cholesterol in men taking beta-blockers. A randomized, controlled trial. Ann Intern Med 1991; 115: 917–924.
Volpe SL, Huang HW, Larpadisorn K, Lesser II. Effect of chromium supplementation and exercise on body composition, resting metabolic rate and selected biochemical parameters in moderately obese women following an exercise program. J Am Coll Nutr 2001; 20: 293–306.
Abraham AS, Brooks BA, Eylath U. The effect of chromium supplementation on serum glucose and lipids in patients with and without non-insulin dependent diabetes. Metabolism 1992; 41: 768–771.
Press RI, Geller J, Evans GW. The effect of chromium picolinate on serum cholesterol and apolipoprotein fractions in human subjects. West J Med 1990; 152: 41–45.
Docherty JP, Sack DA, Roffman M, et al. A double-blind, placebo-controlled exploratory trial of chromium picolinate in atypical depression: effect on carbohydrate craving. J Psychiatr Pract 2005; 11: 302–14.