To study the potential protective effects of these two beverages, researchers looked at 4,923 Japanese patients with type 2 diabetes. The participants were 66 years old on average and were studied over the course of five years.
Each participant filled out a questionnaire detailing their food and drink habits, including how much coffee and green tea they drank each day. Other lifestyle factors, such as smoking, exercise, alcohol consumption, and sleep quality, were also taken into account. Here’s what they found: