The authors of this study noted that previous studies found that drinking four or more cups of coffee per day was associated with a 50% lower risk of diabetes.

They wanted to find out how coffee could decrease risk, and focused their research on human islet amyloid polypeptide (hIAPP).

The misfolding of hIAPP is thought to be a causative factor for type 2 diabetes. The researchers then investigated if the major compounds in coffee — caffeine, caffeic acid, and chlorogenic acid — could block this process.

They found that all the components in coffee did inhibit the formation of toxic hIAPP amyloids, with caffeic acid having the strongest effect and caffeine having the weakest effect.

So, now you know.