The Acute Effects of Specialty Coffee on Cognitive Function in People With Type 2 Diabetes

Following recruitment, interested participants will undertake an online screening session with the experimenter to check the inclusion and exclusion criteria (see section 3). Following this, study procedures will be explained in full by the experimenter and the participants will receive the information sheet (by email) and complete the consent form online. At this point, demographic information and chronic mood measures (BDI and GAD-7) will be collected. At the screening session participants will also undertake a practice version of the online cognitive tests, acute mood measure questionnaires, and an online 24 hour diet recall (ASA24) for familiarisation. The cognitive tests will include digit span text entry, the digit symbol substitution task, Corsi blocks, and an auditory verbal learning test (AVLT). The standardised acute mood measures include the PANAS (outcome measures Positive and Negative Affect) and the Bond-Lader questionnaire (outcome measures alertness, attentiveness, and calmness). These will be adapted for online completion using the Gorilla platform. If able, participants will also self-report the following data relating to their glucose control and cardiovascular health to help characterise the sample: lipid panel (total cholesterol, HDL, LDL, and triglycerides) and HbA1C. Participants will have access this data from their routine type 2 diabetes consultations. On test days, participants will log onto a video conference to meet with the researcher. They will complete the ASA24, cognitive battery, and acute mood measure questionnaires. Then participants will consume the provided coffee within 30 minutes. Participants will have either collected this coffee or have it posted to them alongside brewing equipment, standardised instructions for preparing, and a video demonstrating how to brew the coffee and use the equipment. Patients will log off the video call and will log back on 5 hours after finishing their coffee to undertake the cognitive battery and acute mood measures. No other coffee consumption is permitted during this time and participants will be instructed to consume a lunch low in CGA guided by a list of foods to avoid. They will log back on 24 hours after finishing their coffee to complete the cognitive battery and acute mood measures for the third and final time. For the third time point, participants will be instructed to consume the same breakfast and any coffee they had prior to meeting with the researcher at the first time point; coffee will be permitted in this instance to avoid withdrawal. Upon completing the intervention, participants will be posed questions to explore attitudes about coffee drinking and blood sugar management.