Abstract
Type 2 diabetes mellitus (T2DM) is a serious public health problem. A growing body of evidence suggests that consumption of caffeine leads to disruptions of glucose metabolism that could be of concern for both the development of T2DM and its clinical management. At least 17 studies have consistently demonstrated that caffeine administration in healthy, nondiabetic adults produces an acute increase in insulin resistance or impairment of glucose tolerance, an effect that could contribute to T2DM disease progression in susceptible individuals. Studies of coffee drinkers who have T2DM have found that caffeine exaggerates the rise in glucose after carbohydrate ingestion, an effect that could contribute to higher chronic glucose levels and impaired clinical control. The results of these well-controlled experimental studies contradict epidemiological studies that find that heavy coffee drinking is associated with a lower risk of T2DM. Although it is premature to recommend caffeine abstinence for patients with T2DM and for those at risk, the evidence is sufficient to warrant further study of caffeine's effects, including clinical trials of the potential benefits of eliminating caffeine from the diet.
