Editors' ChoiceDiabetes

Coffee Consumption: It Does a Body Good

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Science Translational Medicine  05 Dec 2012:
Vol. 4, Issue 163, pp. 163ec222
DOI: 10.1126/scitranslmed.3005423

A cup of joe may do more than give you a caffeinated jump start to the day; it may help lower the risk of diabetes. Prior research found an inverse association between coffee and tea consumption—major sources of caffeine—and type 2 diabetes (T2D). Now, Bhupathiraju et al. examine the association of caffeinated versus caffeine-free beverages with T2D risk, to see if caffeine is the beneficial factor.

The authors specifically compared caffeinated and noncaffeinated forms of coffee, tea, sugar-sweetened beverages (SSBs), and carbonated, artificially sweetened beverages. They prospectively observed 74,749 women from the Nurses’ Health Study (1984–2008) and 39,059 men from the Health Professionals Follow-up Study (1986–2008) who were free of diabetes, cardiovascular diseases, and cancer at baseline. Consumption of SSBs, irrespective of the caffeine content, was significantly associated with a higher risk of T2D in women and in men, with relative risk per serving ranging from 11 to 23%. Consumption of coffee, either caffeinated or decaffeinated, was associated with a lower risk of T2D in men and women (relative risk per serving ranging from 4 to 8%). Caffeinated tea consumption affected the groups differently: It was associated with a 5% lower T2D risk in women, but not men. The association between higher SSB consumption and a higher risk of T2D may be due to the high content of sucrose and high-fructose corn syrup of SSBs that increase blood glucose and insulin concentrations. The protective effects of coffee and tea on T2D may be explained by the content of flavonoids in tea and chlorogenic acid in coffee—antioxidants that prevent oxidative stress, which has been linked to the development of diabetes.

This study is limited by the use of an observational study design and self-reported measure of beverage intake. How the different beverages affect T2D is also speculation, with the link between caffeine and diabetes yet unresolved. Despite limitations, these findings by Bhupathiraju et al. could have an impact on public health: All SSBs—caffeinated or not—contribute to a higher risk of T2D; conversely, encouraging people to stick to their morning coffee or tea, rather than replacing with an SSB, may protect the body and thus lower the risk of T2D.

S. N. Bhupathiraju et al., Caffeinated and caffeine-free beverages and risk of type 2 diabetes. Am. J. Clin. Nutr., published online 14 November 2012 (10.3945/ajcn.112.048603). [Full Text]

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