HyperglycemiaNCT05119153
Effects of Coffee Roasting on Blood Sugar Levels in Healthy Humans
A study testing Light Roasted Coffee, Medium Roasted Coffee and Dark Roasted Coffee in people with Hyperglycemia, run by North Carolina State University at 1 site in United States.
Trial summary
The present study determined the effects light, medium, and dark roasted, brewed coffees on blood glucose responses in normal (n = 19) subjects. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Hyperglycemia
- What is being tested?
- Light Roasted Coffee, Medium Roasted Coffee and Dark Roasted Coffee
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 19 participants
- Where
- 1 siteUnited States
- Study dates
- 5 Nov 2019to 31 Oct 2021
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Age 18-64 years old with BMI less than 29 and fasting blood glucose less than 125 mg/dl.
Who cannot join
- Age 18-64 years old with BMI less than 29 and fasting blood glucose less than 125 mg/dl.
- Weight less than 110 pounds (55 kg)
- Pre-existing health conditions, such as:
- High cholesterol
- Hypertension
- Cardiovascular disease
Show all 21Show fewer
- Gastrointestinal motility disorders
- Hypo- or hyperthyroidism
- Anemia
- Renal disease
- Liver disease, including hepatitis B or C, cholestasis, cirrhotic liver disease, or non-alcoholic fatty liver disease
- Chronic or acute pancreatitis
- Diabetes type 1 or 2
- Insulin resistance
- Polycystic ovary syndrome
- Food allergies or intolerances to coffee/caffeine/dairy/corn-based cereals.
- Currently taking prescription medication
- Current smoker
- Consumes more than 3 alcoholic beverages per day
- Pregnant or breastfeeding
- Not willing to take their own blood samples with finger sticks
Trial locations and contacts
1 site in 1 country.
United States1 site
Schaub Hall, Campus Box 7624
Raleigh, North Carolina, 27695
About this study
The present study determined the effects light, medium, and dark roasted, brewed coffees on blood glucose responses in normal (n = 19) subjects.
Read the detailed description
This is a single-blinded, randomized partial block design conducted over 6 weeks in two parts.
In part 1 (3 weeks), participants were randomly assigned to consume four beverages: a placebo containing water and caramel color, light, medium, or dark roast coffee before, during, or after consumption of a beverage containing 50 g of glucose.
In part 2 (3 weeks), participants were randomly assigned to consume four beverages: a placebo containing water and caramel color, light, medium, or dark roast coffee before, during, or after consumption of a standardized breakfast (corn flakes cereal + skim milk) containing 50 g of glucose.
In each part, fasting and postprandial glucose profiles were determined.
- Conditions
- Hyperglycemia
- Being tested
- Placebo Comparator, Light Roasted Coffee, Medium Roasted Coffee, Dark Roasted Coffee
- Keywords
- coffee, glucose challenge, blood glucose levels
- Medical subject headings
- Hyperglycemia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Placebo ComparatorDietary supplement
Placebo designed to mimic coffee color.
Light Roasted CoffeeDietary supplement
12 oz light roast coffee
Medium Roasted CoffeeDietary supplement
12 oz medium roast coffee
Dark Roasted CoffeeDietary supplement
12 oz dark roast coffee
| Study group | Role | What they receive |
|---|---|---|
| Placebo Comparator | Placebo comparator | Placebo composed of water and caramel color. Receives: Dietary Supplement: Placebo Comparator |
| Light Roasted Coffee | Experimental | 12 oz light roast coffee beverage prepared at 55 g ground coffee/L water Receives: Dietary Supplement: Light Roasted Coffee |
| Medium Roasted Coffee | Experimental | 12 oz medium roast coffee beverage prepared at 55 g ground coffee/L water Receives: Dietary Supplement: Medium Roasted Coffee |
| Dark Roasted Coffee | Experimental | 12 oz dark roast coffee beverage prepared at 55 g ground coffee/L water Receives: Dietary Supplement: Dark Roasted Coffee |
What is being measured
The primary outcome is the main question the study is designed to answer.
Changes in Blood Glucose
Each week, fasted baseline and postprandial measurements taken out to 240 minutes
Measured: 6 weeks
Secondary outcomes (1)
Changes in Glucose Area Under the Curve
Used glucose changes over 240 minutes to construct area under the curve
Measured: 6 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Nov 2021
- Study start5 Nov 2019
- Primary completion20 Dec 2020
- Study completion31 Oct 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for HyperglycemiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Randomized, single-blinded, partial block, crossover design
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 19 participants (actual)
Sponsor and investigators
- Lead sponsor
- North Carolina State University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Gabriel Keith Harris, North Carolina State University
- Investigators
- Gabriel K Harris, PhD, Principal investigator, North Carolina State University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05119153
- Sponsor's protocol ID
- 16857
- Status last verified
- Nov 2021
- First submitted
- 31 Oct 2021
- Last updated
- 12 Nov 2021
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Investigators do not plan to share IPD.
Publications
Rayo-Mendez LM, Kinzer C, McMahon J, Nguyen M, Harris GK. Coffee Roast Level, Timing, and Carbohydrate Source Affect Peak Blood Glucose and Area Under the Curve Values in a Randomized Pilot Clinical Trial. J Nutr Metab. 2025 Oct 23;2025:4174563. doi: 10.1155/jnme/4174563. eCollection 2025.
PubMed 41179392
Study at a glance
From the registry record, last updated by the sponsor on 12 Nov 2021. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Coffee Roasting on Blood Sugar Levels in Healthy Humans
- ClinicalTrials.gov ID
- NCT05119153
- Acronym / sponsor ID
- 16857
- Conditions
- Hyperglycemia
- Keywords
- coffee, glucose challenge, blood glucose levels
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 19 participants (actual)
- Lead sponsor
- North Carolina State UniversityUniversity, hospital or other
- Study start
- 5 Nov 2019 (actual)
- Primary completion
- 20 Dec 2020 (actual)
- Study completion
- 31 Oct 2021 (actual)
- First posted
- 12 Nov 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The present study determined the effects light, medium, and dark roasted, brewed coffees on blood glucose responses in normal (n = 19) subjects.
Detailed description
This is a single-blinded, randomized partial block design conducted over 6 weeks in two parts.
In part 1 (3 weeks), participants were randomly assigned to consume four beverages: a placebo containing water and caramel color, light, medium, or dark roast coffee before, during, or after consumption of a beverage containing 50 g of glucose.
In part 2 (3 weeks), participants were randomly assigned to consume four beverages: a placebo containing water and caramel color, light, medium, or dark roast coffee before, during, or after consumption of a standardized breakfast (corn flakes cereal + skim milk) containing 50 g of glucose.
In each part, fasting and postprandial glucose profiles were determined.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 4
- Model description
- Randomized, single-blinded, partial block, crossover design
| Arm | Type | Receives |
|---|---|---|
| Placebo Comparator | Placebo comparator | Dietary Supplement: Placebo ComparatorPlacebo composed of water and caramel color. |
| Light Roasted Coffee | Experimental | Dietary Supplement: Light Roasted Coffee12 oz light roast coffee beverage prepared at 55 g ground coffee/L water |
| Medium Roasted Coffee | Experimental | Dietary Supplement: Medium Roasted Coffee12 oz medium roast coffee beverage prepared at 55 g ground coffee/L water |
| Dark Roasted Coffee | Experimental | Dietary Supplement: Dark Roasted Coffee12 oz dark roast coffee beverage prepared at 55 g ground coffee/L water |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Age 18-64 years old with BMI less than 29 and fasting blood glucose less than 125 mg/dl.
Key exclusion criteria (21 listed)
- Age 18-64 years old with BMI less than 29 and fasting blood glucose less than 125 mg/dl.
- Weight less than 110 pounds (55 kg)
- Pre-existing health conditions, such as:
- Food allergies or intolerances to coffee/caffeine/dairy/corn-based cereals.
- Currently taking prescription medication
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Placebo ComparatorPlacebo designed to mimic coffee color. | Dietary supplement | Placebo Comparator |
| Light Roasted Coffee12 oz light roast coffee | Dietary supplement | Light Roasted Coffee |
| Medium Roasted Coffee12 oz medium roast coffee | Dietary supplement | Medium Roasted Coffee |
| Dark Roasted Coffee12 oz dark roast coffee | Dietary supplement | Dark Roasted Coffee |
Primary outcome
Changes in Blood Glucose
Time frame: 6 weeks
Each week, fasted baseline and postprandial measurements taken out to 240 minutes
1 secondary outcome
Changes in Glucose Area Under the Curve
Time frame: 6 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Nov 2021.
- Derived from this study: PubMed 41179392Rayo-Mendez LM, Kinzer C, McMahon J, Nguyen M, Harris GK. Coffee Roast Level, Timing, and Carbohydrate Source Affect Peak Blood Glucose and Area Under the Curve Values in a Randomized Pilot Clinical Trial. J Nutr Metab. 2025 Oct 23;2025:4174563. doi: 10.1155/jnme/4174563. eCollection 2025.
- Individual participant dataSharing planned: No. Investigators do not plan to share IPD.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Gabriel K Harris, PhD principal investigator
North Carolina State University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Light Roasted Coffee, Medium Roasted Coffee and Dark Roasted Coffee in people with Hyperglycemia, run by North Carolina State University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 21 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 Nov 2021. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Changes in Blood Glucose (time frame: 6 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05119153, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Nov 2021.