A study has found that coffee drinkers appear to be half as likely to develop type 2 diabetes as people who do not drink coffee. The researchers who conducted the study think that this effect may be due to an inflammation-lowering effect of coffee.
Researchers at Harokopio University in Athens studied more than 1,300 men and women age 18 years and older. The participants filled out dietary questionnaires including questions about how much and how often they drank coffee. People who drank less than 1.5 cups of coffee per day were called casual coffee drinkers, and those who drank more than 1.5 cups per day were called habitual drinkers. The study included 816 casual drinkers, 385 habitual drinkers and 239 non-coffee drinkers. Participants also had blood tests to evaluate levels of protein markers of inflammation.
After 10 years, 191 of the participants had developed type 2 diabetes, including 13% of the men and 12% of the women. Habitual coffee drinkers were 54% less likely to develop diabetes when compared to those who did not drink coffee, even after accounting for smoking, high blood pressure, a family history of diabetes, or intake of other caffeinated beverages. Participants who reported higher coffee consumption appeared to have lower likelihoods of developing diabetes.
This study is observational. The researchers did not assign people to either drink coffee or not drink coffee. Because of this there is no way to determine if coffee drinking reduces the risk of developing diabetes, only that there is an association. Other studies have found a correlation between drinking coffee and a lower risk of diabetes, however. Another disadvantage is that the study depends on the participants giving accurate estimates of how much coffee they drink. Some studies have found that the association between coffee and diabetes risk is stronger for women and non-smokers.
The study was published in the European Journal of Clinical Nutrition.