Over the past five years, results from several research studies have shown that drinking coffee may help protect against type 2 diabetes. The mechanism for this protective effect, however, remains unknown. A recent clinical trial involving 47 habitual coffee drinkers was conducted in an effort to better understand the relationship between coffee intake and beneficial health effects (1).
Participants in this study were coffee consumers who did not have type 2 diabetes but were identified as being at risk for the disease. The trial consisted of three levels of coffee intake: 0, 20, and 40 fluid ounces/day of filtered, home-brewed coffee. Blood samples were collected after one month with no coffee intake, after one month of 20 fluid ounces/day (about 2.5 eight-ounce servings of coffee), and after one month of 40 fluid ounces/day (about 5 eight-ounce servings). Compared to no coffee intake, consuming 40 fluid ounces/day resulted in significant reductions in markers of oxidative stress and inflammation, and significant increases in HDL cholesterol levels. These changes have been shown in previous studies to be related to decreased type 2 diabetes risk. No significant changes were observed for blood glucose, LDL cholesterol, or triglycerides.
The findings from this clinical trial provide additional support for lower type 2 diabetes risk with regular coffee intake, possibly through mechanisms related to inflammation, antioxidant properties, or healthier lipid levels.
Kempf K, Herder C, Erlund I, Kolb H, Martin S, Cartensen M, Koenig W, Sundvall J, Bidel S, Kuha S, Tuomilehto J. Effects of coffee consumption on subclinical inflammation and other risk factors for type 2 diabetes: a clinical trial. Am J Clin Nutr 2010;91:950-7.