Impact of Protein Source and Polyphenol Complexation in Protein Bars on Metabolic Health (POLYPRO)

Impact of Consuming Protein and Polyphenol Bars on Metabolic Health

The goal of this clinical trial is to learn if pulse (pea) protein works similar to animal (whey) protein in protein bars consumed by healthy adults.

The main questions it aims to answer are: What are the differences in taste and tolerance profiles between pea and whey proteins? What metabolic and immune changes do participants experience while eating them? What gastrointestinal microbiome shifts can be observed in these participants? How incorporation and complexation of polyphenols with these proteins changes the study outcomes?

Participants will: Consume 1 protein bar with whey protein, pea protein, pea protein with complexed polyphenols, or pea protein with free polyphenols every day for 2 months. Visit the study site at baseline and end of study for checkups and tests. Fill dietary, food acceptance, gastrointestinal tolerance, and global health questionnaires.

Study Overview

• Status: Active, not recruiting
• Conditions: Immune Cells Activity; Metabolic Health; Food Acceptance; Microbiome Composition
• Intervention / Treatment: Other: Whey protein bar; Other: Pea protein bar; Other: Pea protein with complexed polyphenols bar; Other: Pea protein with free polyphenols bar

• Study Type: Interventional
• Enrollment (Actual): 72
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • North Carolina
    • Kannapolis, North Carolina, United States, 28081
      • Plants for Human Health Institute

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• both men and women between the ages of 18-64 years;
• body mass index of 25 and higher;
• generally healthy and without a clinically significant condition (diabetes, infectious disease, or cancer);
• participants must not be pregnant or nursing;
• participants must not be a tobacco user; and
• history of allergies or intolerance to protein bar ingredients.

Exclusion Criteria:

• body mass index lower than 25;
• pregnancy or nursing;
• use of blood sugar lowering medications such as metformin, semaglutide, or insulin;
• use of dietary supplements with polyphenols;
• history of allergies or intolerance to protein bar ingredients;
• noncompliance with the study protocol.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Whey protein bar	Other: Whey protein bar; Whey protein bar
Experimental: Pea protein bar	Other: Pea protein bar; Pea protein bar
Experimental: Pea protein complexed with polyphenols bar; Pea proteins and complexed with blackcurrant polyphenols as a single ingredient	Other: Pea protein with complexed polyphenols bar; Pea protein with complexed polyphenols bar
Experimental: Pea protein with free polyphenols; Pea proteins and blackcurrant polyphenols are two independent ingredients	Other: Pea protein with free polyphenols bar; Pea protein with free polyphenols bar

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Taste	Participants will report taste of the protein bars using a 9-point hedonic scale scored from 1 (dislike extremely) to 9 (like extremely) in a Food Acceptance Questionnaire (FAQ)	At baseline and after 2 months (end of study)
Gastrointestinal tolerance	Gastrointestinal tolerance will be assessed using the Gastrointestinal Tolerability Questionnaire (GTQ) scored on the scale of 0 (absent), 1 (mild), 2 (moderate), or 3 (severe)	At baseline and after 2 months (end of study)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Perceived health	Overall perceived health will be monitored using self-reported wellness status as determined by PROMIS Global-10 questionnaire scored into a physical and mental health components on the scale of 1 (poor), 2 (fair), 3 (good), 4 (very good), or 5 (excellent).	At baseline and after 2 months (end of study)
Fasting insulin	Blood	At baseline and after 2 months (end of study)
Fasting glucose	Blood	At baseline and after 2 months (end of study)
Glycosylated HbA1C	Blood	At baseline and after 2 months (end of study)
triglycerides	Blood	At baseline and after 2 months (end of study)
Cholesterol	Blood	At baseline and after 2 months (end of study)
Homeostatic Model Assessment of Insulin Resistance	The Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) will be calculated using fasting glucose (FG) and fasting insulin (FI) levels to evaluate insulin sensitivity as (FG×FI)/22.5.	At baseline and after 2 months (end of study)

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Immune activation of PMBC cells	Global PMBC transcriptome analysis (DGE RNA-Seq)	At baseline and after 2 months (end of study)
Gastrointestinal microbiome profiles	Changes in fecal microbiome profiles	At baseline and after 2 months (end of study)

Collaborators and Investigators

• Sponsor: North Carolina State University

Publications and helpful links

General Publications

• https://doi.org/10.1111/jfpe.70121

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2025
• Primary Completion (Actual): September 8, 2025
• Study Completion (Estimated): April 1, 2026

Study Registration Dates

• First Submitted: March 5, 2026
• First Submitted That Met QC Criteria: March 19, 2026
• First Posted (Actual): March 23, 2026

Study Record Updates

• Last Update Posted (Actual): March 23, 2026
• Last Update Submitted That Met QC Criteria: March 19, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Amino Acids, Peptides, and Proteins; Proteins; Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Plant Proteins, Dietary; Dietary Proteins; Plant Proteins; Pea Proteins
• Other Study ID Numbers: 26377; 58-3060-1-043 (Other Grant/Funding Number: USDA ARS Pulse Crop Health Initiative)

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