Boston, MA—A Harvard University study provides new insight into the long-term link between coffee consumption and risk of developing type-2 diabetes.
The study, published in Diabetologia, is based off of previous observational data from three large studies: The Nurse’s Health Study, profiling female nurses from the ages of 30–55, the Nurse’s Health Study II, consisting of female nurses between the ages of 25–42, and the Male Professionals Follow-up Study, consisting of men ages 40-7–5. In all three studies, detailed information on diet, lifestyle, medical conditions, and chronic diseases were taken every two to four years for over 20 years. For the purposes of this study, the authors tracked 7,629 type-2 diabetes cases and the amount of tea and coffee they consumed daily, both caffeinated and decaffeinated.
Results of the study showed that participants who increased their consumption by more than one cup a day over a four-year period experienced a 11% lower risk of type-2 diabetes in the following four years, while those that decreased their consumption by one cup or more experienced a 17% increase in risk of type-2 diabetes. In addition “high-stable consumers,” people who consistently had more than three cups of coffee a day, had a 37% overall lower risk than subjects that consumed one or less. While decaffeinated coffee at the baseline was associated with lower risk of diabetes, changes in consumption presented no shift, and tea consumption presented no change in risk at all.
While this certainly presents a correlation between increasing coffee intake and decreasing type-2 diabetes risk, the heads of the research, Frank Hu, M.D., Ph.D., and Shilpa Bhupathiraju, Ph.D., caution that those with conditions associated with high diabetes risk (e.g., high cholesterol, cancer, cardiovascular disease) may have decreased their coffee intake following diagnosis, potentially creating some reverse causation. However, the researchers found that even after excluding these conditions from the data, the trend was still clear.
Published in WholeFoods Magazine, June 2014