The study, which appears today in Archives of Internal Medicine, is a meta-analysis of 457,922 people in 18 studies published between 1966 and 2009 that looked at the link between drinking coffee and diabetes risk. After analyzing the research, the study authors concluded that every extra cup of coffee consumed in one day was correlated with a 7% decrease in the excess risk of diabetes. Even better results were found for bigger coffee and tea consumers--drinking three to four cups a day was associated with about a 25% reduced diabetes risk compared with those who drank between none and two cups day.
Researchers also saw positive results with decaf coffee and tea (some tea varieties do have caffeine, but typically far less than the average cup of coffee). People who drank more than three to four cups of decaf a day had about a one-third lower risk than those who didn't drink any. And tea drinkers who consumed more than three to four cups a day had about a one-fifth lower diabetes risk than non-tea drinkers.