A mildly addictive stimulant, coffee drinking does not always get the best press. Those who want to believe that it is unhealthy, however, have suffered a disappointment with the emergence of a new study that links coffee drinking to a reduced risk of Type 2 diabetes.

A major public health threat, Type 2 diabetes has been on the increase recently in the U.S. and in developed countries generally.

Mark A. Pereira, Ph.D., and colleagues at the University of Minnesota, Minneapolis, tracked coffee intake and diabetes risk in almost 30,000 women over an 11-year period. Published in the June 26 issue of Archives of Internal Medicine, their study found the link between coffee and lowered diabetes risk to be consistent across different ages and body weights. Furthermore, the more coffee an individual generally drinks, the lower their risk for diabetes.

Women who drank more than six cups of any type of coffee per day were 22 percent less likely than those who drank no coffee to develop diabetes; those who drank more than six cups of decaffeinated coffee per day had a 33 percent reduction in risk.

It remains unclear whether it is caffeine or another ingredient in coffee that is responsible. "Magnesium, for which coffee is a good source, could explain some of the inverse association between coffee intake and risk of Type 2 diabetes mellitus through known beneficial effects on carbohydrate metabolism," the authors write. Other minerals and nutrients found in the coffee bean-including polyphenols, which are thought to protect cells in the insulin-producing pancreas-may also contribute to its beneficial effects.