Of carotenoids and diabetes.

People with diabetes can produce large quantities of free radicals in their blood. Because these molecular fragments impair insulin action, researchers have wondered whether chemicals that mop up free radicals head off diabetes. Dietary antioxidants might do just that, a new study hints.

Epidemiologist Earl S. Ford and his colleagues at the Centers for Disease Control and Prevention in Atlanta analyzed data on 1,665 adults, ages 40 to 74. These volunteers, participants in the Third National Health and Nutrition Examination Survey, had all submitted to blood-glucose tests to determine whether they had diabetes. The researchers then compared each individual's diabetic status with his or her blood concentrations of beta-carotene and related plant-based pigments that possess antioxidant properties.

Healthy people had the highest blood concentrations of beta-carotene. Volunteers diagnosed with "impaired glucose tolerance," which can lead to diabetes, had concentrations about 87 percent as high. Among people first diagnosed with diabetes by the study, beta-carotene concentrations were only at 80 percent that of the healthy group. Several other carotenoids in the blood exhibited a similar trend, Ford's team reports in the Jan. 15 American Journal of Epidemiology.

What these data can't answer is which came first: diabetes or low levels of carotenoids. If it's the latter, Ford argues, eating more carrots, kale, and other carotenoid-rich fare might help prevent this disease.