Diet & Fitness

Chromium status appears to be an important factor in glucose metabolism: individuals with lower chromium levels are more likely to have type 2 diabetes or pre-diabetes than those with higher levels, and low chromium status is associated with poor glycemic control and insulin resistance in people with type 2 diabetes.^1,2,3,4 Furthermore, chromium supplementation has been shown to improve glucose control, insulin sensitivity, and other metabolic variables in people with insulin resistance and type 2 diabetes.

In one placebo-controlled trial that included 64 participants with type 2 diabetes and heart disease, taking 200 mcg per day of chromium was associated with greater weight loss, lower fasting glucose and insulin levels, improved insulin sensitivity, and reduced blood pressure after four months. In addition, chromium supplementation led to lower levels of inflammatory markers and higher antioxidant capacity.⁵ A meta-analysis of 28 other randomized controlled trials concluded that chromium supplementation, particularly chromium chloride or chromium picolinate, reduces fasting blood glucose levels, triglyceride levels, and hemoglobin A1c values, and increases HDL-cholesterol levels.⁶ Because of its ability to help regulate dopamine and serotonin activity, some researchers propose chromium may be especially beneficial in people with type 2 diabetes who also suffer from depression or binge eating.⁷

Studies showing beneficial effects from chromium supplementation have generally used 200 mcg per day or more. Many doctors recommend up to 1,000 mcg per day for people with diabetes.

 

Research has shown that supplementing with chromium (200 mcg per day)⁸ or magnesium (340 mg per day)⁹ can prevent blood sugar levels from falling excessively in people with hypoglycemia. Niacinamide (vitamin B3) has also been found to be helpful for hypoglycemic people.¹⁰ Other nutrients, including vitamin C, vitamin E, zinc, copper, manganese, and vitamin B6, may help control blood sugar levels in diabetics.¹¹ Since there are similarities in the way the body regulates high and low blood sugar levels, these nutrients might be helpful for hypoglycemia as well, although the amounts needed for that purpose are not known.

Chromium is a mineral needed in trace amounts by the body. It has been widely studied for its potential benefits in people with insulin resistance and type 2 diabetes.¹² A 23-year observational study found those with poorer baseline chromium status were more likely to develop metabolic syndrome than those with better chromium status.¹³ However, clinical trials examining the effects of chromium supplementation in people with metabolic syndrome have been mixed.

In one placebo-controlled trial with 70 subjects affected by metabolic syndrome, those receiving 300 micrograms of chromium (in the form of chromium-enriched yeast) per day had no changes in measures of glucose and lipid metabolism but had a decrease in resting heart rate.¹⁴ While high heart rate is not typically considered part of metabolic syndrome, it is linked to heart disease. In a placebo-controlled trial that enrolled 59 subjects diagnosed with high glucose levels, insulin resistance, or metabolic syndrome, taking either 500 micrograms or 1,000 micrograms of chromium (as chromium picolinate) daily for six months did not change any of the measured metabolic parameters.¹⁵ Chromium picolinate, at a dose of 1,000 micrograms per day, was also ineffective for improving metabolic markers in a placebo-controlled trial with 63 participants with obesity and metabolic syndrome.¹⁶ Nevertheless, a meta-analysis of 28 randomized controlled trials in people with type 2 diabetes concluded chromium not only improves markers of glucose regulation and insulin sensitivity, but also decreases triglyceride levels and increases HDL-cholesterol levels.¹⁷ The evidence therefore indicates chromium may specifically benefit those with metabolic syndrome co-occurring with type 2 diabetes.

Chromium, a trace mineral that appears to increase the effectiveness of insulin, has been reported to improve blood glucose control in people with various forms of diabetes, including type 1 diabetes. Low chromium levels have been correlated with poor glucose control and human case studies and animal research suggest chromium supplementation may improve glycemic control and prevent some diabetic complications.^{18,19,20,21,22,23} The typical amount of chromium used in studies is 200 micrograms one to three times per day. Supplementation with chromium could potentially enhance the effects of drugs for diabetes (for example, insulin or other blood sugar-lowering agents) and possibly lead to hypoglycemia. Therefore, people with diabetes taking these medications should supplement with chromium only under the supervision of a doctor.

The mineral chromium plays an essential role in the metabolism of carbohydrates and fats and may improve insulin sensitivity.²⁴ Chromium has also been found to enhance weight loss. Three meta-analyses of randomized controlled trials in subjects with overweight and obesity have concluded chromium has a small positive impact on body weight when used in doses of 200–400 micrograms per day for 12–16 weeks.^25,26,27 Some evidence further shows chromium may help in regulating mood and appetite, and one placebo-controlled trial found chromium had positive effects in women with overweight or obesity who also had binge eating disorder: chromium supplementation resulted in reduced frequency of binge eating and greater weight loss compared to placebo, and 1,000 micrograms per day was more effective than 600 micrograms daily.²⁸

Chromium is best known for its ability to improve blood glucose regulation in people with type 2 diabetes. Observational studies have correlated poor chromium status with low HDL-cholesterol²⁹ and high total cholesterol³⁰ levels. A meta-analysis of findings from 38 randomized controlled trial with a combined total of 7,605 participants found chromium supplementation reduced total cholesterol levels slightly. The analysis further noted better results were achieved in trials that used chromium picolinate, used daily doses under 200 micrograms, and lasted less than 12 weeks, as well as in subjects with type 2 diabetes and those under 54 years old.³¹ In a meta-analysis of 24 trials that only enrolled subjects with type 2 diabetes, chromium was similarly found reduce total cholesterol levels as well as raise HDL-cholesterol levels, but its impacts were small.³² However, a meta-analysis of ten trials that included 509 diabetic subjects found chromium had no effect on lipid levels.³³

 

In a double-blind trial, 30 people with type 2 (non-insulin-dependent) diabetes received 200 mcg of chromium per day (as chromium picolinate) for two months and a placebo for an additional two months. The average TG level was significantly lower (by an average of 17.4%) during chromium supplementation than during the placebo period.³⁴Some,^35,36 but not all, trials^37,38 support these findings. It is not clear whether chromium supplementation affects TG levels in non-diabetics, but some evidence suggests that it does not.^{39,40,41,42,36}

Chromium, primarily in a form called chromium picolinate, has been studied for its potential role in altering body composition. Preliminary research in animals and humans suggested that chromium picolinate might increase fat loss and lean muscle tissue gain when used with a weight-training program.^43,44,45 However, most studies have found little to no effect of chromium on body composition or strength.^{46,47,48,49,50} One group of researchers has reported significant reductions in body fat in double-blind trials using 200 to 400 mcg per day of chromium for six to twelve weeks in middle-aged adults,^51,52 but the methods used in these studies have been criticized.⁴⁷

 

There have been five case reports of chromium supplementation (200–400 mcg per day) significantly improving mood in people with a type of depression called dysthymic disorder who were also taking the antidepressant drug sertraline (Zoloft).⁵³ These case reports, while clearly limited and preliminary in scope, warrant further research to better understand the benefits, if any, of chromium supplementation in people with depression.