Research has fairly consistently linked coffee consumption (regular or decaf) to a reduced risk of type 2 diabetes, according to a symposium report from the nonprofit Institute for Scientific Information on Coffee.
Among the research cited is a 2018 analysis of 30 studies involving more than a million people, published in Nutrition Reviews, which found that drinking three or four cups of coffee a day is associated with a 20 percent lower risk of developing diabetes, compared to no coffee. The risk decreased 6 percent for each daily cup of coffee.
The researchers proposed a variety of mechanisms by which bioactive compounds in coffee may help reduce diabetes risk, notably by enhancing insulin sensitivity, having antioxidant or anti-inflammatory effects, increasing resting metabolic rate slightly (and thus weight loss), and by altering the gut microbiota (intestinal microorganisms).
This article first appeared in the UC Berkeley Wellness Letter.