Chromium (Cr): A Comprehensive Scientific Review

Description and Biochemical Composition

Chromium is a transition metal with atomic number 24 in the periodic table. It is found in nature and in the body in various oxidation states, but the biologically active form is usually trivalent chromium (Cr³⁺⁺), i.e. chromium(III). Hexavalent chromium (Cr⁶⁺⁺) is a toxic form and is found in industrial pollution.

The biological role of chromium in the body is poorly understood, but its most well-known role is to facilitate the uptake of glucose into cells by insulin. Chromium is thought to be a component of a molecule called "glucose tolerance factor" (GTF), which optimizes insulin binding to cell receptors and signal transduction. This factor interacts with insulin's receptors on the cell membrane and accelerates the transport of glucose into the cell.

Commonly used forms of chromium supplements include

Chromium Picolinate It is a form in which chromium is chelated with picolinic acid. It is one of the most researched forms and is considered to be highly bioavailable.
Chromium Chloride It is an inorganic chromium salt with less bioavailability.
Chromium Yeast (Brewer's Yeast): It is a naturally occurring source of chromium and contains organically bound chromium.
Chromium Nicotinate It is a form in which chromium is bound with niacin (vitamin B3).

Effects on bodily functions

The potential effects of chromium on the body are predominantly related to blood sugar control and metabolic syndrome.

Blood Sugar Control and Diabetes: The best-known benefit of chromium is that it helps regulate blood sugar levels by increasing insulin sensitivity. This effect may be particularly pronounced in people with Type 2 diabetes or insulin resistance. By helping to transport glucose into cells more efficiently, chromium can reduce blood sugar fluctuations.
- Research Example: A meta-analysis by Cao et al. (2007) indicated that chromium supplementation may provide significant benefits in lowering glucose and insulin levels in patients with Type 2 diabetes. However, its effectiveness may depend on the individual situation and the presence of chromium deficiency. Some later studies have shown that the effect is less pronounced in healthy individuals or in well-controlled diabetics, especially if there is no obvious deficiency (Pittler et al., 2007).
- New Research: Recent research emphasizes that the efficacy of chromium varies according to the individual's chromium status (deficiency or not), the severity of diabetes and the form of chromium used. It is thought to be particularly beneficial in individuals with insulin resistance or prediabetes (Aaseth et al., 2020).
Weight Management: Due to chromium's effect on blood sugar control, some research has examined its potential to reduce appetite and aid weight loss. However, the evidence in this area is limited and it has been noted that chromium alone does not induce significant weight loss, but may have some indirect effects on body composition (fat loss, preservation of muscle mass).
- Research Example: A meta-analysis by Onakpoya et al. (2015) showed that chromium picolinate had a small but statistically significant effect on weight loss, but more research is needed for clinically meaningful weight loss.
Cholesterol and Lipid Metabolism: Some studies have suggested that chromium supplementation may help lower total cholesterol, LDL ("bad") cholesterol and triglyceride levels, while increasing HDL ("good") cholesterol levels. These effects may be associated with improved insulin sensitivity.
- Research Example: A review by Yazdani et al. (2014) indicated that chromium supplementation has potential benefits in improving lipid profiles in diabetic and dyslipidemic patients.
Immune System: There are limited data on the specific effects of chromium directly on the immune system. However, improving overall metabolic health and indirectly reducing inflammation may support immune function. In particular, given that metabolic disorders such as diabetes may weaken the immune system, chromium's improvement of metabolic health may indirectly support the immune response.
Inflammation Research on the anti-inflammatory effects of chromium is ongoing. Insulin resistance and metabolic syndrome are often associated with chronic low-grade inflammation. Chromium's improvement of insulin sensitivity may indirectly reduce this inflammation.
- Research Example: Some animal studies have shown that chromium supplementation can reduce inflammatory markers, but evidence in humans is still limited (Sahin et al., 2004).
Cardiovascular Health: The potential positive effects of chromium on blood glucose and lipid metabolism may indirectly contribute to reducing the risk of cardiovascular disease. Insulin resistance and high blood sugar are important risk factors for cardiovascular disease.
Physical Performance: Research on the direct physical performance-enhancing effects of chromium has yielded conflicting results. Some athletes use chromium in the belief that it can increase muscle mass or accelerate fat burning. However, strong scientific evidence supporting these claims is limited. Given chromium's role in energy metabolism, it could potentially optimize post-exercise glucose utilization.
- Research Example: A review by Lukaski (2000) noted that the effects of chromium supplementation on muscle mass or strength were generally minimal.
Reproductive Health: Scientific evidence on the direct and specific effects of chromium on reproductive health is very limited. However, improved metabolic health and insulin sensitivity may provide indirect benefits for women with reproductive problems associated with insulin resistance, such as polycystic ovary syndrome (PCOS).
- Research Example: Some small studies have suggested that chromium supplementation may improve insulin resistance and associated metabolic abnormalities in women with PCOS (Jamilian & Asemi, 2017).

Areas of Use

Chromium supplements are mainly used in the following cases:

Blood Sugar Control: To help blood glucose regulation in individuals with type 2 diabetes, prediabetes or insulin resistance.
Weight Management: Supporting weight loss programs, however, is not a solution in itself.
Nutrition Support: To provide supplementation in individuals with inadequate dietary chromium intake or at risk of chromium deficiency.

Side Effects and Dosage Information

Chromium supplements are generally considered safe at recommended doses. However, side effects may occur in overdoses or in some sensitive individuals.

Side Effects:

Gastrointestinal Disorders: Rarely, stomach upset, nausea, diarrhea or constipation may occur.
Skin Reactions: People with hypersensitivity may experience skin rashes.
Kidney and Liver Problems: Reports of kidney or liver damage at very high doses and with prolonged use are rare. However, these cases are usually associated with use well above recommended doses and exposure to hexavalent chromium may also be a factor.
Low Blood Sugar (Hypoglycemia): When used together with diabetes medicines (insulin or oral antidiabetics), it can cause blood sugar to drop too low (hypoglycemia).
Drug Interactions:
- Diabetes Medicines: Increases the risk of hypoglycemia when used in combination with insulin or oral antidiabetic drugs. Blood glucose levels should be closely monitored and drug dosages adjusted.
- Levothyroxine May affect the absorption of thyroid hormone medications. There should be a break of several hours between chromium supplementation and levothyroxine.
- Antacids Antacids can reduce the absorption of chromium.

Dosage

The recommended daily intake (RDA) or adequate intake (AI) for chromium varies according to age and gender:

Adult Men (19-50 years): 35 mcg/day
Adult Women (19-50 years): 25 mcg/day
Pregnant Women: 30 mcg/day
Breastfeeding Women: 45 mcg/day

Supplement Dosages: Chromium supplements usually contain much higher doses (e.g. 200 mcg to 1000 mcg) of elemental chromium. These doses are mainly used for specific therapeutic purposes, such as blood sugar control or weight management.

For Blood Sugar Control: Usually 200-400 mcg/day of chromium picolinate is used. Higher doses (600-1000 mcg) have been used in some studies, but these doses should be taken under the supervision of a health professional.
Upper Intake Limit (UL): There is as yet no established upper intake limit (UL) for chromium. This is because it is difficult to over-intake chromium in the normal diet and the risk of toxicity in supplement forms is generally low. However, at very high doses and long-term use, potential side effects should be considered.

It is imperative to consult a healthcare professional (doctor, dietitian, pharmacist) before using any chromium supplements, especially if you have a chronic health condition such as diabetes, kidney or liver disease, or if you take regular medication.

Storage Conditions

Chromium supplements are generally stable formulations but must be stored properly to maintain their quality:

Cool and Dry Environment: Store in a cool (usually room temperature) and dry place away from moisture and excessive heat. It should not be exposed to direct sunlight.
Original Packaging: Storing the product in its original, tightly sealed packaging minimizes contact with air and moisture and maintains the stability of the product.
Out of the reach of children: Like all supplements, it should be kept in a safe place out of the reach of children.

Conclusion and Future Research

Chromium is a trace element of particular interest for its potential role in blood glucose control and insulin sensitivity. Forms such as chromium picolinate have shown potential to help blood glucose regulation in individuals with Type 2 diabetes, prediabetes and insulin resistance. However, the benefits may be less pronounced in healthy individuals or those with well-controlled diabetes. Its effects on weight management and cardiovascular health are indirect and need further research. While supplement use is generally safe, caution should be exercised, especially due to interactions with diabetes medications and rare side effects at very high doses. Future research should delve deeper into the mechanisms of action of chromium, compare the bioavailability and efficacy of different forms of chromium, and better understand the impact of individual chromium deficiency status on supplement response. In particular, long-term, large-scale, randomized controlled human studies will provide a clearer picture of the therapeutic potential and safety of chromium.

Sources

Aaseth, J., Alexander, J., & Bjørklund, G. (2020). The effect of chromium on diabetes mellitus and associated complications: A review. Journal of Trace Elements in Medicine and Biology, 61, 126582.
Cao, H., & Anderson, R. A. (2007). Chromium in diabetes and cardiovascular disease. Journal of Trace Elements in Medicine and Biology, 21(1), 1-10.
Jamilian, M., & Asemi, Z. (2017). The effect of chromium supplementation on insulin resistance, serum lipids and markers of inflammation in patients with polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials. Gynecological Endocrinology, 33(10), 795-800.
Lukaski, H. C. (2000). Chromium as an ergogenic aid. International Journal of Sport Nutrition and Exercise Metabolism, 10(3), 332-342.
Onakpoya, I. J., Posadzki, P., & Ernst, E. (2015). Chromium for weight loss and glycemic control: a systematic review and meta-analysis of randomized controlled trials. Obesity Reviews, 16(5), 415-422.
Pittler, M. H., & Ernst, E. (2007). Chromium picolinate for reducing body weight: a systematic review and meta-analysis of randomized clinical trials. International Journal of Obesity, 31(6), 957-962.
Sahin, K., Sahin, N., & Kucuk, O. (2004). Effects of chromium supplementation on metabolic parameters in rats fed a high-fat diet. Journal of Animal Physiology and Animal Nutrition, 88(9-10), 374-380.
Yazdani, A., Mozaffari, M., & Amini, J. (2014). The effect of chromium supplementation on lipid profile in patients with type 2 diabetes mellitus: A meta-analysis. Journal of Diabetes & Metabolic Disorders, 13(1), 74.