Effect of Extruded Cereals Enriched With β-glucan on Postprandial Plasma Glucose and Serum Insulin Responses

Effect of Extruded Cereals Enriched With β-glucan From Oats or Barley on Postprandial Plasma Glucose and Serum Insulin Responses in Generally Healthy Adults

β-glucan (BG) is a viscous dietary fiber present in barley and oats that, when added to carbohydrate containing foods, reduces the postprandial glycemic response (PPGR), which is considered to be beneficial to health. In 2011, the European Food Safety Authority (EFSA) concluded that 4g of either oat BG (OBG) or barley BG (BBG) per 30g available carbohydrate (avCHO) is required to obtain a reduction in PPGR, however this is an impractically large amount of BG to incorporate into palatable foods. A recent systematic review and meta-analysis found that doses of OBG well below 4g/30g avCHO can significantly reduce PPGR.

It is therefore hypothesized that 25g avCHO portions of cereal containing 1.4-1.5g of either OBG or BBG will elicit a statistically significantly lower PPGR compared to a control cereal containing no BG.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Other: Control Cereal; Other: OBG Cereal; Other: BBG Cereal

Detailed Description

Statistical Analysis:

Analysis populations: The intention-to-treat (ITT) population includes all subjects who consumed at least 1 of the 3 test meals in that phase. The per-protocol (PP) population for each phase includes all subjects who completed all 3 tests in that phase with no serious protocol violations. There may also be a group, termed PPDO (dropouts), defined as the PP population plus subjects who competed 1 or 2 of the 3 tests with no serious protocol violations.

Conclusions will be based on the glucose and insulin endpoints for the PP population. To assess the potential impact of excluding those subjects who dropped out after completing 1 or 2 tests, a secondary analysis will be performed for the PP+DO population where the missing values are imputed using methods described by Snedecor and Cochran.

Distribution of data: the methods of analyzing continuous data assume that the data are normally distributed. Normality of distribution will be tested by comparing the actual distribution of the Z scores to the expected distribution using the chi-square test with the data taken to be normally distributed if p>0.05. Non-normally distributed data will be transformed by (in order of preference) log-transformation, square-root-transformation, some other method, until the transformed data are normally distributed.

Primary endpoint: the primary endpoint will be assessed as follows: serum glucose concentrations will be subjected to repeated-measures analysis of variance (ANOVA) using the linear model analyzing for the main effects of time and treatment and the time×treatment interaction. After demonstrating a significant time×treatment interaction (indicating that the pattern of glucose response differs significantly among treatments), the values for iAUC 0-2h will be analyzed by ANOVA for the main effect of treatment; after demonstrating significant heterogeneity, the mean for each of the 2 test cereals will be compared only to that of each respective control cereal using Dunnett's Test to adjust for multiple comparisons. The 2 test cereals will not be compared to each other. The criterion for significance will be two-tailed p<0.05.

Secondary endpoints: the results for insulin iAUC will be assessed as described for the primary endpoint. Serum glucose and insulin concentrations and increments at each time point will be subjected to repeated-measures ANOVA. Upon demonstration of significant heterogeneity, individual means of the test and matched control cereals will be compared using Dunnett's Test to adjust for multiple comparisons. The 2 test cereals will not be compared to each other. The criterion for significance will be two-tailed p<0.05.

Statistical Power:

The average within-individual CV of glucose iAUC elicited by repeated tests of oral glucose is within the range of 22-25% in our previous studies in healthy individuals. To demonstrate that both test cereals differ significantly from the control, each comparison must have 90% power to detect a significant difference in order to obtain 80% power to detect both significant differences (since 0.902 = 0.81). Assuming a SD of 25% and using the normal distribution, n=40 subjects provide 95% power to detect a significant difference of 20% between test and control cereals.

• Study Type: Interventional
• Enrollment (Actual): 42
• 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: 20 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Individuals who are non-pregnant, non-lactating aged 20-65 years of age, inclusive.
• Body mass index 18.0 to 29.9 kg/m², inclusive.
• Nonsmokers (tobacco, cannabis, vaping).
• Fasting glucose concentration <7.0 mmol/L (126 mg/dL), determined by a fasting finger-stick blood sample (plasma) at screening.
• Willing to abstain from unusual levels of food intake, unusual or strenuous exercise, smoking or consuming alcoholic drinks 24 hours before study days.
• Understanding the study procedures and willing to provide informed consent to participate in the study and authorization to release relevant protected health information to the study investigator.
• Willing to comply with the protocol.
• Subjects must be eligible to receive income in Canada and be covered by a health insurance plan such as the Ontario Health Insurance Plan.

Exclusion Criteria:

• Failure to meet any one of the inclusion criteria.
• Systolic blood pressure ≥160 mm Hg or diastolic blood pressure ≥100 mm Hg at screening.
• Change in body weight of >3.5kg (>7.7 lbs.) within 4 weeks of the screening visit.
• Practicing any extreme dietary habits, as judged by the Investigator (i.e., Atkins diet, very high protein diet, etc.).
• Major trauma or major medical or surgical event within 3 months of screening.
• History or presence of clinically important endocrine, cardiovascular, pulmonary, biliary, or gastrointestinal disorders.
• The use of medications known to influence carbohydrate metabolism, including, but not limited to adrenergic blockers, thiazolidinediones, metformin, and systemic corticosteroids, or with any condition or use of any medication which might, in the opinion of the Qualified Investigator (QI), either: 1) make participation dangerous to the subject or to others, or 2) affect the results.
• Use of supplements containing chromium (intended for glucose management), ginseng or cinnamon, within 3 weeks of screening.
• Changes in the doses of permissible prescription drugs within 3 months of screening or changes in the doses of over-the-counter drugs or permissible supplements within 3 weeks of screening.
• History of cancer in the prior two years, except for non-melanoma skin cancer.
• Recent history (within 12 months of screening) or strong potential for alcohol or substance abuse, where alcohol abuse is defined as > 14 drinks per week (1 drink=12 oz beer, 5 oz wine, or 1.5 oz distilled spirits).
• Known intolerance, sensitivity, or allergy to any ingredients in the study test meals.
• Unwillingness or inability to comply with the experimental procedures and to follow INQUIS health and safety policies.
• Subject is currently participating or recently (within 30 days of screening) participated in a clinical trial involving long-term exposure (greater than 24 hours) to an investigational drug, nutritional supplement, or lifestyle modification.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Control Cereal; A portion of cereal (25g available carbohydrate) that contains no beta-glucan	Other: Control Cereal; A portion of cereal (25g available carbohydrate), served with 125ml of 2% milk and 250ml water, will be fed to participants and postprandial glucose and insulin will be measured
Experimental: OBG Cereal; A portion of cereal (25g available carbohydrate) that contains approximately 1.4g of oat beta-glucan (OBG)	Other: OBG Cereal; A portion of cereal (25g available carbohydrate) containing OBG, served with 125ml of 2% milk and 250ml of water, will be fed to participants and postprandial glucose and insulin will be measured
Experimental: BBG Cereal; A portion of cereal (25g available carbohydrate) that contains approximately 1.4g of barley beta-glucan (BBG)	Other: BBG Cereal; A portion of cereal (25g available carbohydrate) containing BBG, served with 125ml of 2% milk and 250ml of water, will be fed to participants and postprandial glucose and insulin will be measured

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postprandial Glucose Incremental Area under the Curve (iAUC) from 0-2 hours	iAUC, ignoring area below baseline, will be calculated from glucose concentrations in plasma obtained from finger prick blood samples. The mean glucose concentration at -5 and 0 minutes will be taken as the baseline.	Plasma glucose will be measured for 2 hours after consumption of the cereals (timepoints: -5, 0, 15, 30, 45, 60, 90, and 120 minutes)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak Rise of glucose	the maximum postprandial increments (peak rises) of glucose defined as the maximum concentration achieved minus the baseline (mean of concentrations at -5 and 0 min)	Glucose will be measured over 2 hours postprandially (timepoints: -5, 0, 15, 30, 45, 60, 90, and 120 minutes)
Peak Rise of insulin	the maximum postprandial increments (peak rises) of insulin defined as the maximum concentration achieved minus the baseline (mean of concentrations at -5 and 0 min)	Insulin will be measured over 2 hours postprandially (timepoints: -5, 0, 15, 30, 45, 60, 90, and 120 minutes)
Gmax	The maximum postprandial concentration of glucose (Gmax) achieved over the 2h test period	Glucose will be measured over 2 hours postprandially (timepoints: -5, 0, 15, 30, 45, 60, 90, and 120 minutes)
Imax	The maximum postprandial concentration of insulin (Imax) achieved over the 2h test period	Insulin will be measured over 2 hours postprandially (timepoints: -5, 0, 15, 30, 45, 60, 90, and 120 minutes)
Time of Gmax	The time when the maximum postprandial concentration of glucose (Gmax) occurred during 2h test period	Insulin will be measured over 2 hours postprandially (timepoints: -5, 0, 15, 30, 45, 60, 90, and 120 minutes)
Time of Imax	The time when the maximum postprandial concentration of insulin (Imax) occurred during 2h test period	Insulin will be measured over 2 hours postprandially (timepoints: -5, 0, 15, 30, 45, 60, 90, and 120 minutes)
Glucose concentrations and increments at each time point	Glucose concentrations and increments at each time point	Glucose will be measured over 2 hours postprandially (timepoints: -5, 0, 15, 30, 45, 60, 90, and 120 minutes)
Insulin concentrations and increments at each time point	Insulin concentrations and increments at each time point	Glucose and insulin will be measured over 2 hours postprandially (timepoints: -5, 0, 15, 30, 45, 60, 90, and 120 minutes)
Postprandial Insulin iAUC from 0-2 hours	iAUC, ignoring area below baseline, will be calculated from insulin concentrations in serum obtained from finger prick blood samples. The mean insulin concentration at -5 and 0 minutes will be taken as the baseline.	Serum insulin will be measured for 2 hours after consumption of the cereals (timepoints: -5, 0, 15, 30, 45, 60, 90, and 120 minutes)

Collaborators and Investigators

• Sponsor: Société des Produits Nestlé (SPN)
• Collaborators: Cereal Partners Worldwide; INQUIS Clinical Research
• Investigators: Principal Investigator: Thomas Wolever, DM, PhD, INQUIS Clinical Research

Study record dates

Study Major Dates

• Study Start (Actual): March 4, 2024
• Primary Completion (Actual): April 26, 2024
• Study Completion (Actual): June 26, 2024

Study Registration Dates

• First Submitted: September 22, 2022
• First Submitted That Met QC Criteria: September 26, 2022
• First Posted (Actual): September 27, 2022

Study Record Updates

• Last Update Posted (Estimated): July 1, 2025
• Last Update Submitted That Met QC Criteria: June 26, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Keywords: Barley; Oats; Postprandial glucose; Postprandial insulin; Beta Glucan
• Other Study ID Numbers: INQ-2203

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