A morning cup of coffee may help prevent diabetes, a new report in the Archives of Internal Medicine, U.S. Tuesday claimed, adding caffeine apparently has little to do with the effect. Researchers compared the coffee consumption habits of 28,812 women enrolled in the Iowa Women's Health Study in U.S. and found that the women who drank the most coffee -- especially decaffeinated varieties -- were 22 percent less likely to develop diabetes than women who didn't consume coffee. Researchers do not know which ingredients in coffee provide the protective benefit; although it is known that caffeine does not reduce diabetes risk. Two other components of coffee, magnesium and phytate, do not appear to affect risk either. "In our study, for whatever reason, it doesn't look like caffeine has anything to do with it," said lead researcher Mark A. Pereira.