[Does coffee protect against type 2 diabetes?].

The prevention of type 2 diabetes has become a major public health objective. Cross-sectional studies have shown a lower prevalence of type 2 diabetes among coffee drinkers. The present article synthesizes results of recent prospective studies, which assessed the relative risk of developing type 2 diabetes according to coffee consumption. Most studies confirm a protective effect against type 2 diabetes, with some dose-response in function of the degree of daily coffee consumption. The observed effect is rather impressive (relative risk reduced to almost 0.70-0.40) and is present whatever the type of population. It appears equal, or event greater, with decaffeinated coffee as compared to regular coffee. These results suggest that the protective effect could not be attributed exclusively to caffeine, but rather that it should be explained by other components, most probably chlorogenic acid and/or various anti-oxidants. The precise mechanism explaining the protection of coffee against type 2 diabetes and its potential relevance in public health remain to be specified.