(Extraído de nccam.nih.gov)
The dietary supplement chromium picolinate does not improve insulin resistance or impaired glucose tolerance in people at risk for developing type 2 diabetes, according to a recent study published in the journal Endocrine Practice. Previous research has suggested that chromium picolinate may help people with type 2 diabetes by improving insulin resistance and increasing the body's sensitivity to insulin. However, its effects on people at risk for developing type 2 diabetes have not been largely studied.
This double-blind, randomized, placebo-controlled, crossover study enrolled 59 adults who had impaired fasting glucose, impaired glucose tolerance, or metabolic syndrome. Impaired fasting glucose and impaired glucose tolerance, also called pre-diabetes, are conditions in which blood glucose levels are higher than normal but not high enough for a diagnosis of diabetes. Metabolic syndrome is often characterized by abdominal obesity, impaired fasting glucose, elevated blood pressure, and high cholesterol and triglycerides.
Participants were randomly assigned to receive 500 mcg or 1,000 mcg of chromium picolinate daily, and then were further divided into groups that received a sequence of either chromium picolinate (500 mcg or 1,000 mcg, daily) or placebo. After 6 months, the groups crossed over to the alternate assignment (i.e., groups that initially received chromium supplements then received placebo, and vice versa) for another 6 months. Because the time required for chromium to wash out of the body fully is unknown, researchers conducted a 6-month post-treatment assessment following the intervention.
After 6 months of the intervention and after the 6-month post-treatment assessment, the researchers observed no change in glucose or insulin levels in participants who received either dosage of chromium, compared with placebo. In addition, there were no improvements in weight, waist circumference, blood pressure, cholesterol, or triglycerides.
The researchers noted that participants' chromium levels were not assessed upon enrollment or during the intervention, a major limitation of the study. Despite this and other limitations, they concluded that chromium is unlikely to reduce the risk of developing type 2 diabetes and suggested that endocrinologists not recommend this therapy as part of a diabetes prevention strategy.
- Ali A, Ma Y, Reynolds J, et al. Chromium effects on glucose tolerance and insulin sensitivity in persons at risk for diabetes mellitus. Endocrine Practice. 2011;17(1):16–25.