Chromium & Disease Treatment

Type 2 (non-insulin dependent) diabetes

Type 2 diabetes is characterized by elevated blood glucose levels and insulin resistance. Although insulin levels in type 2 diabetics may be higher than in healthy individuals, the physiological effects of insulin are reduced. Because chromium is known to enhance the action of insulin, the relationship between chromium nutritional status and type 2 diabetes has generated considerable scientific interest. Individuals with type 2 diabetes have been found to have higher rates of urinary chromium loss than healthy individuals, especially those with diabetes of more than 2 years duration. Prior to 1997, well-designed studies of chromium supplementation in individuals with type 2 diabetes showed no improvement in blood glucose control, though they provided some evidence of reduced insulin levels and improved blood lipid profiles. In 1997, the results of a placebo-controlled trial conducted in China indicated that chromium supplementation might be beneficial in the treatment of type 2 diabetes. One hundred eighty participants took either a placebo, 200 mcg/day, or 1,000 mcg/day of chromium in the form of chromium picolinate. At the end of four months, blood glucose levels were 15%-19% lower in those that took 1,000 mcg/day compared with those that took a placebo. Blood glucose levels in those that took 200 mcg/day did not differ significantly from those that took a placebo. Insulin levels were lower in those who took either 200 mcg/day or 1,000 mcg/day. Glycosylated hemoglobin levels, a measure of long-term control of blood glucose, were also lower in both chromium-supplemented groups, but they were lowest in the group taking 1,000 mcg/day. Because the chromium nutritional status of the Chinese participants was not evaluated, and the prevalence of obesity was much lower than is typically associated with type 2 diabetics in the U.S., extrapolation of these results to a U.S. population is difficult. However, the findings in the Chinese population emphasize the need for large-scale randomized controlled trials of chromium supplementation for type 2 diabetes in the U.S.

Gestational diabetes

Few studies have examined the effects of chromium supplementation on gestational diabetes. Gestational diabetes occurs in about 2% of pregnant women and usually appears in the second or third trimester of pregnancy. Blood glucose levels must be tightly controlled to prevent adverse effects on the developing fetus. After delivery, glucose tolerance generally reverts to normal. However, 30% to 40% of women who have had gestational diabetes develop type 2 diabetes within 5 to 10 years. An observational study in pregnant women did not find serum chromium levels to be associated with measures of glucose tolerance or insulin resistance in late pregnancy, although serum chromium levels may not reflect tissue chromium levels. Women with gestational diabetes whose diets were supplemented with 4 mcg of chromium per kilogram of body weight daily as chromium picolinate for 8 weeks had decreased fasting blood glucose and insulin levels compared with those who took a placebo. However, insulin therapy rather than chromium picolinate was required to normalize severely elevated blood glucose levels.

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