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

The Effects of Drinking Specialty Coffee on Cognition in People With Type 2 Diabetes

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.

Study Overview

• Status: Completed
• Conditions: Type 2 Diabetes
• Intervention / Treatment: Other: Coffee

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Berkeley, California, United States, 94720
      • Berkeley

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 30 years or more
• Formal diagnosis of Type 2 Diabetes for 1 year or more
• Current coffee drinkers, 4 or fewer cups daily (a cup is 8 oz)

Exclusion Criteria:

• Consuming on average more than 5 cups of coffee daily
• Regularly consuming specialty coffee (participants will be provided with a list of these coffees)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Low Polyphenol coffee; Participants will be provided with a conventional, low CGA coffee to brew and consume which contains less CGA than the experimental arm.	Other: Coffee; 12 ounces of coffee will be consumed
Experimental: High Polyphenol coffee; Participants will be provided with a single origin, CGA rich specialty coffee as graded by the Specialty Coffee Association of America's Q-grading system to brew and consume	Other: Coffee; 12 ounces of coffee will be consumed

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Short term Memory	The Rey Auditory Verbal Learning Test (RAVLT) will present two lists of 15 words each, which will be played via audio recording after which participants will be asked to recite as many words as they can remember.	0 hours
Short term Memory	The Digit Span Forward Task will show a series of numbers in a specific order which participants will be asked to type out in the order shown	0 hours
Short term Memory	The Corsi Block Tapping task will present participants with a screen of blocks that light up in a sequence which participants will have to remember and tap the blocks in the order shown; the sequence lengthens or shortens based on participants performance.	0 hours
Processing Speed	A computerised version of the Digit Symbol Substitution Test (DSST) will be used to assess processing speed. Participants will be given a legend with numbers corresponding to symbols, then presented with a specific pair of number/symbol. They will then determine if that pair is a match or a mismatch, and respond accordingly. They will be measured for speed and accuracy.	0 hours
Processing Speed	A computerised version of the Digit Symbol Substitution Test (DSST) will be used to assess processing speed. Participants will be given a legend with numbers corresponding to symbols, then presented with a specific pair of number/symbol. They will then determine if that pair is a match or a mismatch, and respond accordingly. They will be measured for speed and accuracy.	5 hours
Processing Speed	A computerised version of the Digit Symbol Substitution Test (DSST) will be used to assess processing speed. Participants will be given a legend with numbers corresponding to symbols, then presented with a specific pair of number/symbol. They will then determine if that pair is a match or a mismatch, and respond accordingly. They will be measured for speed and accuracy.	24 hours
Long Term Memory	Long term memory will be assessed using the Rey Auditory Verbal Learning Test (RAVLT), where participants will be asked to recall as many words as possible from the previous two lists words heard earlier.	0 hours
Long Term Memory	Long term memory will be assessed using the Rey Auditory Verbal Learning Test (RAVLT), where participants will be asked to recall as many words as possible from the previous two lists words heard earlier.	5 hours
Long Term Memory	Long term memory will be assessed using the Rey Auditory Verbal Learning Test (RAVLT), where participants will be asked to recall as many words as possible from the previous two lists words heard earlier.	24 hours
Source Monitoring	Source monitoring will be assessed using a modified version of the Rey Auditory Verbal Learning Test (RAVLT) where a third "distractor" list will be presented, after which participants will be asked to recognize if a word is one heard in the original two lists, or a new word. If participants respond the former, they will then be asked to identify which list they heard the word from.	0 hours
Source Monitoring	Source monitoring will be assessed using a modified version of the Rey Auditory Verbal Learning Test (RAVLT) where a third "distractor" list will be presented, after which participants will be asked to recognize if a word is one heard in the original two lists, or a new word. If participants respond the former, they will then be asked to identify which list they heard the word from.	5 hours
Source Monitoring	Source monitoring will be assessed using a modified version of the Rey Auditory Verbal Learning Test (RAVLT) where a third "distractor" list will be presented, after which participants will be asked to recognize if a word is one heard in the original two lists, or a new word. If participants respond the former, they will then be asked to identify which list they heard the word from.	24 hours
Short term Memory	The Rey Auditory Verbal Learning Test (RAVLT) will present two lists of 15 words each, which will be played via audio recording after which participants will be asked to recite as many words as they can remember.	5 hours
Short term Memory	The Corsi Block Tapping task will present participants with a screen of blocks that light up in a sequence which participants will have to remember and tap the blocks in the order shown; the sequence lengthens or shortens based on participants performance.	5 hours
Short term Memory	The Digit Span Forward Task will show a series of numbers in a specific order which participants will be asked to type out in the order shown	5 hours
Short term Memory	The Rey Auditory Verbal Learning Test (RAVLT) will present two lists of 15 words each, which will be played via audio recording after which participants will be asked to recite as many words as they can remember.	24 hours
Short term Memory	The Digit Span Forward Task will show a series of numbers in a specific order which participants will be asked to type out in the order shown	24 hours
Short term Memory	The Corsi Block Tapping task will present participants with a screen of blocks that light up in a sequence which participants will have to remember and tap the blocks in the order shown; the sequence lengthens or shortens based on participants performance.	24 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mood	Positive affect will be measured using the Positive and Negative Affect Schedule (PANAS). The ratings (a scale of 1-5) for the 10 positive items will be summed to get a Positive Affect (PA) score. Scores can range from 10 to 50, with higher scores indicated higher levels of PA	0 hours
Mood	Negative affect will be measured using the Positive and Negative Affect Schedule (PANAS). The ratings (a scale of 1-5) for the 10 negative items will be summed to get a Negative Affect (NA) score. Scores can range from 10 to 50, with higher scores indicated higher levels of PA	0 hours
Mood	Mood will be measured using the Bond-Lader Visual Analogue Scale (BL-VAS) where participants rate their mood by marking a continuous line between two extreme endpoints, typically ranging from "not at all" to "extremely." The values are averaged into three categories (alertness, contentedness, and calmness) and higher scores indicate higher experiencing of each category.	0 hours
Mood	Mood will be measured using the Immediate Mood Scaler (IMS), which captures current mood states using 7-point Likert scales. The total score is calculated by summing all 22 items, with higher scores indicating more negative mood states	0 hours
Mood	Positive affect will be measured using the Positive and Negative Affect Schedule (PANAS). The ratings (a scale of 1-5) for the 10 positive items will be summed to get a Positive Affect (PA) score. Scores can range from 10 to 50, with higher scores indicated higher levels of PA	5 hours
Mood	Negative affect will be measured using the Positive and Negative Affect Schedule (PANAS). The ratings (a scale of 1-5) for the 10 negative items will be summed to get a Negative Affect (NA) score. Scores can range from 10 to 50, with higher scores indicated higher levels of PA	5 hours
Mood	Mood will be measured using the Bond-Lader Visual Analogue Scale (BL-VAS) where participants rate their mood by marking a continuous line between two extreme endpoints, typically ranging from "not at all" to "extremely." The values are averaged into three categories (alertness, contentedness, and calmness) and higher scores indicate higher experiencing of each category.	5 hours
Mood	Mood will be measured using the Immediate Mood Scaler (IMS), which captures current mood states using 7-point Likert scales. The total score is calculated by summing all 22 items, with higher scores indicating more negative mood states	5 hours
Mood	Positive affect will be measured using the Positive and Negative Affect Schedule (PANAS). The ratings (a scale of 1-5) for the 10 positive items will be summed to get a Positive Affect (PA) score. Scores can range from 10 to 50, with higher scores indicated higher levels of PA	24 hours
Mood	Negative affect will be measured using the Positive and Negative Affect Schedule (PANAS). The ratings (a scale of 1-5) for the 10 negative items will be summed to get a Negative Affect (NA) score. Scores can range from 10 to 50, with higher scores indicated higher levels of PA	24 hours
Mood	Mood will be measured using the Bond-Lader Visual Analogue Scale (BL-VAS) where participants rate their mood by marking a continuous line between two extreme endpoints, typically ranging from "not at all" to "extremely." The values are averaged into three categories (alertness, contentedness, and calmness) and higher scores indicate higher experiencing of each category.	24 hours
Mood	Mood will be measured using the Immediate Mood Scaler (IMS), which captures current mood states using 7-point Likert scales. The total score is calculated by summing all 22 items, with higher scores indicating more negative mood states	24 hours

Collaborators and Investigators

• Sponsor: University of Reading

Study record dates

Study Major Dates

• Study Start (Actual): November 9, 2023
• Primary Completion (Actual): August 23, 2024
• Study Completion (Actual): August 23, 2024

Study Registration Dates

• First Submitted: February 20, 2024
• First Submitted That Met QC Criteria: February 11, 2026
• First Posted (Actual): February 19, 2026

Study Record Updates

• Last Update Posted (Actual): February 19, 2026
• Last Update Submitted That Met QC Criteria: February 11, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Nutritional and Metabolic Diseases; Diabetes Mellitus, Type 2; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Beverages; Plant Preparations; Biological Products; Complex Mixtures; Coffee
• Other Study ID Numbers: UReading Acute Coffee Diabetes

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No