From Harvard: Caffeinated and caffeine-free beverages and risk of type 2 diabetes

http://www.ncbi.nlm.nih.gov/pubmed/23151535

Am J Clin Nutr. 2012 Nov 14. [Epub ahead of print]

Caffeinated and caffeine-free beverages and risk of type 2 diabetes.

Bhupathiraju SN, Pan A, Malik VS, Manson JE, Willett WC, van Dam RM, Hu FB.

Source

Departments of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA; Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.

Abstract

BACKGROUND:

Consumption of caffeinated beverages such as coffee and tea has been associated with a lower risk of type 2 diabetes (T2D). Paradoxically, short-term metabolic studies have shown that caffeine impairs postprandial glycemic control.

OBJECTIVE:

The objective was to prospectively examine the association of caffeinated compared with caffeine-free beverages, including coffee, tea, sugar-sweetened beverages (SSBs), and carbonated artificially sweetened beverages (ASBs), with T2D risk.

DESIGN:

We prospectively observed 74,749 women from the Nurses' Health Study (NHS, 1984-2008) and 39,059 men from the Health Professionals Follow-Up Study (HPFS, 1986-2008) who were free of diabetes, cardiovascular diseases, and cancer at baseline.

RESULTS:

We documented 7370 incident cases of T2D during 24 y of follow-up in the NHS and 2865 new cases during 22 y of follow-up in the HPFS. After major lifestyle and dietary risk factors were controlled for, caffeinated and caffeine-free SSB intake was significantly associated with a higher risk of T2D in the NHS (RR per serving: 13% for caffeinated SSB, 11% for caffeine-free SSB; P < 0.05) and in the HPFS (RR per serving: 16% for caffeinated SSB, 23% for caffeine-free SSB; P < 0.01). Only caffeine-free ASB intake in NHS participants was associated with a higher risk of T2D (RR: 6% per serving; P < 0.001). Conversely, the consumption of caffeinated and decaffeinated coffee was associated with a lower risk of T2D [RR per serving: 8% for both caffeinated and decaffeinated coffee in the NHS (P < 0.0001) and 4% for caffeinated and 7% for decaffeinated coffee in the HPFS (P < 0.01)]. Only caffeinated tea was associated with a lower T2D risk among NHS participants (RR per serving: 5%; P < 0.0001).

CONCLUSION:

Irrespective of the caffeine content, SSB intake was associated with a higher risk of T2D and coffee intake was associated with a lower risk of T2D.