Several studies have indicated that drinking between three to five cups of coffee per day could reduce the risk of developing type 2 diabetes and cardiovascular disease. However, most of this research has involved observational studies that cannot reliably establish causal effects due to other potentially influential factors, as well as the difficulty to disentangle any specific effects of caffeine from the other components included in caffeinated drinks and foods. Now, an international team of scientists led by the Karolinska Institute in Sweden has used Mendelian randomization...