Caffeine is known to reduce sensitivity to insulin (responsible for the metabolism of glucose), although other components of coffee such as magnesium and chlorogenic acid could offer some health benefits. Rob van Dam and colleagues from the Dutch national Institute for Public Health and the Environment, Bilthoven, Netherlands, prospectively assessed the effect of varying coffee consumption on the development of type 2 diabetes in around 17,000 Dutch adults. They report how individuals with high coffee consumption-those who drank seven or more cups of coffee a day-were 50% less likely to develop type-2 diabetes compared with less frequent coffee drinkers (two cups a day or less), even when confounding factors (e.g. smoking, alcohol consumption, and body mass) were taken into account.
Rob van Dam comments: "Caffeine acutely lowers insulin sensitivity, but long-term effects are unknown. In an intervention study, increased coffee consumption for 14 days reduced fasting plasma glucose, whereas substitution of regular coffee for decaffeinated coffee for 20 days did not affect plasma glucose. That study did not include a control group, but the results suggested that components of coffee other than caffeine could be beneficial for glucose metabolism. In view of the widespread use of coffee and the large health burden of type 2 diabetes, our finding of an inverse association between coffee consumption and risk of type 2 diabetes could have important public-health implications. However, our findings need to be replicated and possible adverse effects on other health aspects should be considered in the choice to consume coffee."
Contact:
Rob M van Dam, Department of Nutrition and Health, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1085,
1081 HV Amsterdam, Netherlands;
T) 31-20-444-6948;
F) 31-20-444-6940;
E) robvdam@bio.vu.nl
(Alternative contact): Dr Edith Feskens,
T) 31-30-274-3479.
The Lancet