Researchers found women who drank more than four cups of regular or decaffeinated coffee per day have significantly lower levels of a component of insulin than non-coffee drinkers. Higher levels are linked to the development of type 2 diabetes.
This insulin component is called C-peptide. High levels of C-peptide indicate that the body is unable to use insulin properly, a condition known as insulin resistance, which is a major risk factor for type 2 diabetes.
The results of the study were presented this week at the American Heart Association's Scientific Sessions 2004.
Coffee May Fight Diabetes
Previous studies have linked drinking coffee to a lower risk of type 2 diabetes as well as other health benefits. But researchers aren't sure how coffee lowers these risks.
In this study, researchers looked at the relationship between women's coffee-drinking habits and the level of C-peptide in the blood. Using the records of more than 2,000 women who participated in the Nurses' Health Study, researchers compared how much regular or decaffeinated coffee the women said they drank from 1984-1990 and the level of C-peptide in blood samples taken in 1990.
They found that the more coffee the women drank, the lower the level of C-peptide. Women who drank more than four cups of regular or decaffeinated coffee had C-peptide levels that were 13% and 14% lower, respectively, than women who never drank coffee.
This relationship between caffeinated coffee and C-peptide levels was even stronger in obese and overweight women, who had 22% and 18% lower levels of this hormone component, respectively, compared to non-coffee drinkers.
Researchers say the results suggest that caffeine as well as other elements in coffee may work separately as well as together in lowering the risk of type 2 diabetes by preventing insulin resistance. They say long-term studies are needed to investigate the effects of both caffeinated and decaffeinated coffee on insulin resistance and other risk factors for diabetes.