Coffee has been found to have beneficial effects on cognitive function and blood sugar control. Benefits include reduced risk of cognitive decline and improved performance on cognitive tests, as well as reduced risk of diabetes and improved blood sugar control in people with diabetes, a population that is at a higher risk of cognitive decline. These effects have been observed for both caffeinated and decaffeinated coffee, and have been associated with the polyphenol chlorogenic acid (CGA). This polyphenol has been found to be more bioavailable in certain coffees, known as "speciality coffee" as defined by the Specialty Coffee Association of America, depending on agriculture, roasting, and brewing method.
This current project will bring together these previous findings to explore the effects of specialty coffee on cognitive function in people with type 2 diabetes through a repeated measures trial with two conditions: a high CGA specialty coffee group and a conventional coffee control group. Participants will consume each beverage 1 week apart and will be tested before consumption, 5 hours after consumption, and 24 hours after consumption based on findings that CGA metabolism takes up to 36 hours. At the beginning and the end of each condition participants will undertake a cognitive assessment online using the Gorilla platform, and a series of questionnaires relating to health and mood measures (details in procedure).
In regard to key ethical issues, all participants will be coffee consumers therefore participants will be accustomed to consuming coffee and no adverse events are expected. The quantities of coffee to be consumed do not exceed the recommended daily intake of caffeine. The study will not impact on the participants ongoing management of their type 2 diabetes. Participants will be free to withdraw from the study any point without giving reason.