Determination of the Glycemic Index of Products Varying in Levels of Refined and Whole Grain Corn

Determination of the Glycemic Index of Products Varying in Levels of Refined and Whole Grain Corn: a Randomized Controlled Trial in Healthy Participants

Interest in identifying low GI foods and the food factors responsible for the low GI of foods has increased. Three corn products with varying levels of refined and whole grain corn will be compared to each other and to a dextrose control. It is hypothesized that higher levels of whole grain corn present in a food will decrease the rate of absorption and result in a lower postprandial glucose levels and glycemic index, and that the whole grain ingredient manufacturing process impacts whole grain ingredient benefits.

Study Overview

• Status: Completed
• Conditions: Glycemic Index; Glycemic Load
• Intervention / Treatment: Other: Dextrose control; Other: Corn snack containing 25 grams available carbohydrate

• Study Type: Interventional
• Enrollment (Actual): 29
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5C 2N8
      • INQUIS Clinical Research

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Adults aged 18-75 years, inclusive.
• BMI between 18.0 and 35.0 Kg/m2.
• Willing to abstain from unusual strenuous exercise and consuming alcoholic drinks for 24 hours before study days.
• Willing to refrain from smoking tobacco or marijuana for 12h before and during study visits.
• Willing to maintain habitual diet, physical activity pattern, and body weight throughout the trial.
• Understanding the study procedures & willing to provide informed consent to participate in the study & authorization to release relevant protected health information to the study investigator.
• Participants must be eligible to receive income in Canada and be covered by a health insurance plan such as OHIP.

Exclusion Criteria:

• Self-reported pregnant or breastfeeding women.
• Known history of gastrointestinal disease (e.g., diverticulitis, Crohns disease, coeliac disease etc.), bariatric surgery, AIDS, hepatitis, a history or presence of clinically important endocrine (including Type 1 or Type 2 diabetes mellitus), or any condition which might, in the opinion of the medical director either: 1) make participation dangerous to the participant or to others, or 2) affect the results.
• Use of medications known to influence carbohydrate metabolism, gastrointestinal function or appetite, including, but not limited to adrenergic blockers, diuretics, thiazolidinediones, metformin and systemic corticosteroids within 4 weeks of the screening visit, or any medication which might, in the opinion of the medical director either: 1) make participation dangerous to the participant or to others, or 2) affect the results.
• Major trauma or surgical event within 3 months of screening.
• Unwillingness or inability to comply with the experimental procedures and to follow INQUIS health and safety policies.
• Known intolerance, sensitivity or allergy to test products.
• Participation in any clinical trial within the past 30 days (with the exception of routine GI testing of commonly consumed foods) or any PepsiCo sponsored trial within the past 3 months.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Dextrose control; Consumed at two visits (first and last of 5 test days). Solution contains 25g of available carbohydrates (27.3g dextrose monohydrate) mixed with 250 ml of water. Served with 250 ml additional water.	Other: Dextrose control; A solution containing 25g of available carbohydrates on 2 separate occasions
Active Comparator: Control food; Refined corn snack, served with 250 ml water	Other: Corn snack containing 25 grams available carbohydrate; Varying amounts of whole-grain corn from none to some to more
Experimental: Test food A; Whole grain corn snack, manufacturer A, served with 250 ml water	Other: Corn snack containing 25 grams available carbohydrate; Varying amounts of whole-grain corn from none to some to more
Experimental: Test food B; Whole grain corn snack, manufacturer B, served with 250 ml water	Other: Corn snack containing 25 grams available carbohydrate; Varying amounts of whole-grain corn from none to some to more

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
iAUC (incremental area under the curve)	Compare the plasma glucose in mmol/L of three corn products	Change from fasting baseline (-5 minutes and 0 minutes) to 15, 30, 45, 60, 90 and 120 minutes after test snack consumed within 10 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Glycemic Index (GI)	Compare the plasma glucose in mmol/L of three products with varying levels of refined and whole grain corn vs. dextrose control	Change from fasting baseline (-5 minutes and 0 minutes) to 15, 30, 45, 60, 90 and 120 minutes after test snack consumed within 10 minutes
Glycemic load (GL)	Calculate the GI x (grams available carbohydrate in a serving) where a serving is 28 grams of each of the three corn products	Change from fasting baseline (-5 minutes and 0 minutes) to 15, 30, 45, 60, 90 and 120 minutes after test snack consumed within 10 minutes
Incremental glucose levels	Compare glucose levels in mmol/L at individual timepoints after each of three corn products	Change from fasting baseline (-5 minutes and 0 minutes) to 15, 30, 45, 60, 90 and 120 minutes after test corn snack consumed within 10 minutes

Collaborators and Investigators

• Sponsor: PepsiCo Global R&D
• Investigators: Principal Investigator: Thomas MS Wolever, MD, PhD, INQUIS Clinical Research, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): January 8, 2026
• Primary Completion (Actual): March 12, 2026
• Study Completion (Actual): March 12, 2026

Study Registration Dates

• First Submitted: January 6, 2026
• First Submitted That Met QC Criteria: February 16, 2026
• First Posted (Actual): February 23, 2026

Study Record Updates

• Last Update Posted (Actual): March 16, 2026
• Last Update Submitted That Met QC Criteria: March 13, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: whole grain; corn; refined; iAUC
• Additional Relevant MeSH Terms: Skin Diseases; Keratosis; Skin and Connective Tissue Diseases; Callosities
• Other Study ID Numbers: PEP-2510

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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