Effects on Glycemia and Insulinemia of Different Grape Varieties (SUGARGAP)

Assessment of the Effect of Different Varieties of Grapes on Postprandial Glycemia and Insulinemia

The goal of this intervention study is to examine the glucose increase in blood, during 2 hours after consuming different varieties of grapes, in men and women with normal or excess body weight. The main question it aims to answer is:

can a variety of red grape reduce the glucose curve compared to a reference variety?

Participants will have to attend the Center for nutrition research facilities in three occasions, fasted for at least 8 hours. Once there, they will be measured and monitored. A canula will be inserted and once they finish eating 300g of grapes, blood extractions will be performed at minutes 15, 30, 60, 90 and 120.

Study Overview

• Status: Completed
• Conditions: Healthy; Glycaemic Response Measurements
• Intervention / Treatment: Other: Grape variety control; Other: Grape variety 1; Other: Grape variety 2

Detailed Description

The main purpose of this study is to evaluate how the glucose and insulin curves develop after consuming different grapes varieties. Still, we also want to evaluate how the serum metabolome changes with the three varieties after 120 minutes. Therefore, a metabolomic study will be done in samples of volunteers at this time point.

The intervention is longitudinal and in three arms (one per variety). Due to the harvest of the different varieties, it cannot be crossover, but each subject will consume the three varieties.

At each visit, the subjects will undergo the same schedule:

• Arrival in a fasting state of at least 8 hours.
• Insertion of cannula and extraction of fasting samples
• Consumption of approximately 300 g of grapes (50 g of Carbohydrates).
• Extraction of blood samples at 15, 30, 60, 90 and 120 minutes.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Spain
  • Navarra
    • Pamplona, Navarra, Spain, 31008
      • Center for Nutrition Research. University of Navarra

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Baseline glycaemia between 70 and 100 mg/dL
• BMI between 18.5 kg/m2 and 29.9 kg/m2.
• Absence of disease or alterations related to gastrointestinal status.
• Signed written informed consent.

Exclusion Criteria:

• Glycaemic levels out of the reference inclusion criteria (below 70 or over 100 mg/dL)
• Subjects presenting BMI out of the limits set.
• Subjects with unstable body weight the three months prior the start of the study (+/- 3 Kg)
• Subjects not able to attend the preestablished visits
• Women pregnant or lactating
• Subjects undergoing pharmacological treatment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Non-Randomized
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Variety 1 (timpson); Reference variety	Other: Grape variety control; Reference grape variety
Active Comparator: Variety 2 (18INV-1438-10); First comparator	Other: Grape variety 1; First grape variety to evaluate
Active Comparator: Variety 3 (18-1465-110); Second comparator	Other: Grape variety 2; Second grape variety to evaluate

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Glycaemic response	Assessment of serum glucose evolution after consuming 50 g of carbohydrates in grapes	0 minutes
Glycaemic response	Assessment of serum glucose evolution after consuming 50 g of carbohydrates in grapes	15 minutes
Glycaemic response	Assessment of serum glucose evolution after consuming 50 g of carbohydrates in grapes	30 minutes
Glycaemic response	Assessment of serum glucose evolution after consuming 50 g of carbohydrates in grapes	60 minutes
Glycaemic response	Assessment of serum glucose evolution after consuming 50 g of carbohydrates in grapes	90 minutes
Glycaemic response	Assessment of serum glucose evolution after consuming 50 g of carbohydrates in grapes	120 minutes
Insulinemic response	Assessment of serum insulin evolution after consuming 50 g of carbohydrates in grapes	0 minutes
Insulinemic response	Assessment of serum insulin evolution after consuming 50 g of carbohydrates in grapes	15 minutes
Insulinemic response	Assessment of serum insulin evolution after consuming 50 g of carbohydrates in grapes	30 minutes
Insulinemic response	Assessment of serum insulin evolution after consuming 50 g of carbohydrates in grapes	60 minutes
Insulinemic response	Assessment of serum insulin evolution after consuming 50 g of carbohydrates in grapes	90 minutes
Insulinemic response	Assessment of serum insulin evolution after consuming 50 g of carbohydrates in grapes	120 minutes
Insulin Resistance Index (HOMA-IR) response	Assessment of insulin resistance evolution after consuming 50 g of carbohydrates in grapes	0 minutes
Insulin Resistance Index (HOMA-IR) response	Assessment of insulin resistance evolution after consuming 50 g of carbohydrates in grapes	15 minutes
Insulin Resistance Index (HOMA-IR) response	Assessment of insulin resistance evolution after consuming 50 g of carbohydrates in grapes	30 minutes
Insulin Resistance Index (HOMA-IR) response	Assessment of insulin resistance evolution after consuming 50 g of carbohydrates in grapes	60 minutes
Insulin Resistance Index (HOMA-IR) response	Assessment of insulin resistance evolution after consuming 50 g of carbohydrates in grapes	90 minutes
Insulin Resistance Index (HOMA-IR) response	Assessment of insulin resistance evolution after consuming 50 g of carbohydrates in grapes	120 minutes
Metabolome composition	Metabolomic analysis after grapes consumption	120 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total cholesterol	Serum total cholesterol in fasting state	0 minutes
LDL - cholesterol	Serum LDL-cholesterol in fasting state	0 minutes
HDL-cholesterol	Serum HDL-cholesterol in fasting state	0 minutes
Triglycerides	Serum triglycerides in the fasting state	0 minutes
ALT	Serum ALT levels in fasting state	0 minutes
AST	Serum AST levels in fasting state	0 minutes

Collaborators and Investigators

• Sponsor: Clinica Universidad de Navarra, Universidad de Navarra
• Investigators: Principal Investigator: Santiago Navas-Carretero, PhD, University of Navarra

Study record dates

Study Major Dates

• Study Start (Actual): June 25, 2024
• Primary Completion (Actual): November 29, 2024
• Study Completion (Actual): November 29, 2024

Study Registration Dates

• First Submitted: December 19, 2024
• First Submitted That Met QC Criteria: December 19, 2024
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: December 19, 2024
• Last Verified: November 1, 2024

More Information

Terms related to this study

• Keywords: metabolome; Glycaemic response; insulin response; Grape variety
• Other Study ID Numbers: SUGARGAP

Plan for Individual participant data (IPD)

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

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No