Effects of Coffee Roasting on Blood Sugar Levels in Healthy Humans

The present study determined the effects light, medium, and dark roasted, brewed coffees on blood glucose responses in normal (n = 19) subjects.

Study Overview

• Status: Completed
• Conditions: Hyperglycemia
• Intervention / Treatment: Dietary supplement: Placebo Comparator; Dietary supplement: Light Roasted Coffee; Dietary supplement: Medium Roasted Coffee; Dietary supplement: Dark Roasted Coffee

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 Type: Interventional
• Enrollment (Actual): 19
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • North Carolina
    • Raleigh, North Carolina, United States, 27695
      • Schaub Hall, Campus Box 7624

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age 18-64 years old with BMI less than 29 and fasting blood glucose less than 125 mg/dl.

Exclusion Criteria:

• 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
  • 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

Study Plan

How is the study designed?

Design Details

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

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo Comparator; Placebo composed of water and caramel color.	Dietary supplement: Placebo Comparator; Placebo designed to mimic coffee color.
Experimental: Light Roasted Coffee; 12 oz light roast coffee beverage prepared at 55 g ground coffee/L water	Dietary supplement: Light Roasted Coffee; 12 oz light roast coffee
Experimental: Medium Roasted Coffee; 12 oz medium roast coffee beverage prepared at 55 g ground coffee/L water	Dietary supplement: Medium Roasted Coffee; 12 oz medium roast coffee
Experimental: Dark Roasted Coffee; 12 oz dark roast coffee beverage prepared at 55 g ground coffee/L water	Dietary supplement: Dark Roasted Coffee; 12 oz dark roast coffee

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in Blood Glucose	Each week, fasted baseline and postprandial measurements taken out to 240 minutes	6 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in Glucose Area Under the Curve	Used glucose changes over 240 minutes to construct area under the curve	6 weeks

Collaborators and Investigators

• Sponsor: North Carolina State University
• Investigators: Principal Investigator: Gabriel K Harris, PhD, North Carolina State University

Study record dates

Study Major Dates

• Study Start (Actual): November 5, 2019
• Primary Completion (Actual): December 20, 2020
• Study Completion (Actual): October 31, 2021

Study Registration Dates

• First Submitted: October 31, 2021
• First Submitted That Met QC Criteria: November 10, 2021
• First Posted (Actual): November 12, 2021

Study Record Updates

• Last Update Posted (Actual): November 12, 2021
• Last Update Submitted That Met QC Criteria: November 10, 2021
• Last Verified: November 1, 2021

More Information

Terms related to this study

• Keywords: coffee; blood glucose levels; glucose challenge
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Hyperglycemia
• Other Study ID Numbers: 16857

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Investigators do not plan to share IPD.

Drug and device information, study documents

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