Postprandial Effect of Isocaloric Challenge Meals Enriched With Indigenous Fruits and Vegetables on Glucose Metabolism in Individuals With Type 2 Diabetes in Wakiso District, Uganda

The goal of this clinical trial is to evaluate changes in glucose and lipid levels after consuming challenge meals enriched with selected indigenous fruits and vegetables in people living with type 2 diabetes in Wakiso district.

The main question to answer is:

Does the consumption of challenge meals enriched with indigenous fruits and vegetables improve glucose and lipid levels among people living with type 2 diabetes? Researchers will compare the effects of different challenge meals on glucose and lipid levels to identify the indigenous fruit and vegetable with the strongest glucose- and lipid-lowering effects.

Participants will:

Consume five challenge meals over 5 weeks. Visit the study site after a 5-7 day rest period to consume the challenge meal and complete the tests.

Study Overview

• Status: Recruiting
• Conditions: Type 2 Diabetes; Cardiometabolic Health
• Intervention / Treatment: Other: Indigenous Fruit and vegetable.; Other: Challenge meal that resembles the oral glucose tolerance test.

Detailed Description

In a postprandial study, cardiometabolic health outcomes will be assessed on each 3-hour test day, comprising the consumption of one challenge meal enriched with any of the three indigenous fruits and vegetables. The three indigenous fruits and vegetables will include: Hibiscus sabdariffa (Hibiscus), Solanum anguivi (Forest bitter berries), and Tamarindus indica (Tamarind). A preliminary sensory evaluation involving the freeze-dried indigenous fruits and vegetable powder prototypes was conducted. The prototypes were formulated based on fruit pulp, vegetable and calyx proportions (25g, 50g and 100g). The prototypes were subjected to a sensory evaluation (acceptability and preference tests) using untrained panellists (n = 10). After the sensory study, the 25g prototypes had the highest scores. However, due to variation in polyphenol profiles in the three indigenous fruits and vegetable powders, the 50g prototypes were selected to ensure an adequate polyphenol dose. The study participants will be randomly allocated to consume one challenge meal enriched with one of the three indigenous fruit and vegetable-based powders on each study day. There will be an additional two reference challenge meals administered to determine within-subject variability. A 5 to 7-day washout period will be observed between each postprandial study to prevent any carryover effect. The participants in the study will not be informed of the ingredients in the challenge meals. The total study duration will be 5 weeks. Measurements will be performed on each study visit.

• Study Type: Interventional
• Enrollment (Estimated): 8
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Tonny Kiyimba, PhD; Phone Number: +256706923575; Email: tonny.kiyimba1@gmail.com
• Study Contact Backup: Name: Fred Kigozi, MSc; Phone Number: +256701530822; Email: fred.kigozi49@gmail.com

Study Locations

• Uganda
  • Wakiso, Uganda
    • Recruiting
    • Kajjansi Health Centre IV
    • Contact: Fred Kigozi; Phone Number: 312210200; Email: fred.kigozi49@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Fasting blood sugar >= [7 mmol/L](based on medical records)
• Diabetic regimen for at least 6 months
• Type 2 diabetes
• Plans to continue staying in the same location for the next 6 months

Exclusion Criteria:

• Taking dietary supplements
• Type 1 diabetes
• Tuberculosis co-infection
• Renal failure
• Liver cirrhosis
• Chronic pancreatitis
• Pregnancy and Lactation
• Regular sports activity
• Parallel participation in another clinical trial
• On treatment for dyslipidaemia,
• On treatment for hypertension
• Very low blood pressure (< 90/50 mmHg)
• Allergic reactions to test products

Study Plan

How is the study designed?

Design Details

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

Number of Arms

5

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Challenge meal enriched with Hibiscus sabdariffa (Hibiscus)	Other: Indigenous Fruit and vegetable.; Indigenous fruit and vegetable freeze dried powder.
Experimental: Challenge meal enriched with Solunum anguivi (Forest bitter berries)	Other: Indigenous Fruit and vegetable.; Indigenous fruit and vegetable freeze dried powder.
Experimental: Challenge meal enriched withTamarindus indica (Tamarind)	Other: Indigenous Fruit and vegetable.; Indigenous fruit and vegetable freeze dried powder.
Active Comparator: Reference meal one	Other: Challenge meal that resembles the oral glucose tolerance test.; Isocaloric challenge meal
Active Comparator: Reference meal two	Other: Challenge meal that resembles the oral glucose tolerance test.; Isocaloric challenge meal

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incremental area under the curve blood glucose	Blood glucose analysis for blood samples collected at 8 different time points:0, 15, 30, 60, 90, 120, 150 and 180 minutes	From enrollment at each of the five postprandial visits, until the end of the postprandial study which will last five weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incremental area under the curve blood triglyceride	Blood Triglyceride analysis for blood samples collected at 8 different time points:0, 15, 30, 60, 90, 120, 150 and 180 minutes	From enrollment at each of the five postprandial visits, until the end of the postprandial study which will last five weeks
Incremental area under the curve high density lipoprotein cholestrol (HDL)	Blood HDL analysis for blood samples collected at 8 different time points:0, 15, 30, 60, 90, 120, 150 and 180 minutes	From enrollment at each of the five postprandial visits, until the end of the postprandial study which will last five weeks
Incremental area under the curve low density lipoprotein cholestrol (LDL)	Blood LDL analysis for blood samples collected at 8 different time points:0, 15, 30, 60, 90, 120, 150 and 180 minutes	From enrollment at each of the five postprandial visits, until the end of the postprandial study which will last five weeks
Incremental area under the curve total cholestrol	Blood cholestrol analysis for blood samples collected at 8 different time points:0, 15, 30, 60, 90, 120, 150 and 180 minutes	From enrollment at each of the five postprandial visits, until the end of the postprandial study which will last five weeks
Incremental area under the curve plasma polyphenol metabolites	Plasma polyphenol metabolite analysis for blood samples collected at 8 different time points:0, 15, 30, 60, 90, 120, 150 and 180 minutes	From enrollment at each of the five postprandial visits, until the end of the postprandial study which will last five weeks
Incremental area under the curve appetite visual analog scores	Appetite visual analog scores analysis at 8 different time points:0, 15, 30, 60, 90, 120, 150 and 180 minutes	From enrollment at each of the five postprandial visits, until the end of the postprandial study which will last five weeks
Palatability visual analog scores	Palatability visual analog scores analysis at one time point:15 minutes	From enrollment at each of the five postprandial visits, until the end of the postprandial study which will last five weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body mass Index (BMI)	BMI will be calculated using height and weight	BMI will be calculated only on day one of the study that lasts five weeks
Fat mass	Bioelectrical impedence analysis will be performed	Fat mass will be calculated only on day one of the study that lasts five weeks
Waist circumference	Wait circumference will be measured using a measuring tape	Waist circumference will be calculated only on day one of the study that lasts five weeks

Collaborators and Investigators

• Sponsor: KU Leuven
• Investigators: Principal Investigator: Christophe Matthys, Phd, KU Leuven University, Belgium

Study record dates

Study Major Dates

• Study Start (Actual): May 18, 2026
• Primary Completion (Estimated): August 30, 2026
• Study Completion (Estimated): August 30, 2026

Study Registration Dates

• First Submitted: December 3, 2025
• First Submitted That Met QC Criteria: December 16, 2025
• First Posted (Actual): December 19, 2025

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 19, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Type 2 diabetes; Postprandial; Glucose metabolism; Challenge meals; Indigenous fruits and Vegetables
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Nutritional and Metabolic Diseases; Diabetes Mellitus, Type 2; Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Vegetables
• Other Study ID Numbers: Postprandial studies

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

Individual Participant Data (IPD) Sharing Statement Plan to Share IPD:

Plan Description: All the data generated during this study will comply with the prevailing standards and guidelines in documenting and depositing data sets.

The results from this research will be disseminated in presentations at public lectures, scientific institutions and meetings, and/or publication in reputable journals. Data sharing will be performed in compliance with the International Committee of Medical Journal Editors. Individual de-identified participant data will be shared. In particular, individual participant data that underlie the results reported in our articles, after de-identification (text, tables, figures and appendices).

Supporting Materials: Study Protocol Informed Consent Form (ICF) Analytic Code Time Frame: Data will become available from 9-36 months after the publication of the study results by the research team.

Access Criteria: Data will only be shared with investigators

• IPD Sharing Time Frame: 9 to 18 months after article publication.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

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