Grape Polyphenols and Second-meal Effect (GRAPESECOND)

Potential Modulatory Effect of Whole Grape on Second-meal Tolerance in Obese Subjects: Role of Polyphenols

The aim of this is study is to evaluate the effects of a single intake of grapes (a polyphenol-rich food) in postprandial metabolism in subjects with obesity, including a first intake (high-fat breakfast) after overnight fasting a second one (medium-fat lunch). Studies on the effects of polyphenols on postprandial (glucidic and lipidic) metabolism have commonly been performed in animal models and have used grape extracts, ignoring the whole pool of polyphenols present in grapes (extractable and non-extractable polyphenols). Besides, the contribution of polyphenols to the so-called second-meal effect has not been explored. It should be highlighted that this study aims to explore the potential beneficial role of fresh grapes, consumed as fruit; in order to ensure the stability of the product, they will be provided as freeze-dried milled material, but the amount received by the subjects could be incorporated into a common diet, being equivalent to 300 g of fresh grapes.

Study Overview

• Status: Completed
• Conditions: Obesity
• Intervention / Treatment: Other: Freeze-dried grape (GRAP)/Placebo (PLA)

Detailed Description

Twenty-five subjects with obesity will be were recruited. Detailed inclusion and exclusion criteria are provided below.

The subjects will receive, after overnight fasting, either a monodose of freeze-dried grapes (equivalent to 300 g of fresh grapes) or isocaloric placebo solved in water, together with a high-fat breakfast. Blood samples will be collected before the intake, up to 5 h after breakfast, then a medium-fat lunch will be provided and blood samples will be collected for three additional hours. Both interventions will be separated by two weeks. The following determinations will be performed in blood samples collected at different periods: glucose, insulin, triglycerides, uric acid, viscosity, antioxidant capacity. Additionally, a satiety test will be provided. It is expected that grape supplementation, as compared with an isocaloric placebo, causes significant modifications in all the parameters indicated. Nevertheless, the primary outcome of this study is the area under the curve for glucose after the second meal (300-420 min from basal time).

• Study Type: Interventional
• Enrollment (Actual): 25
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Spain
  • Madrid, Spain, 28040
    • Institute of Food Science, Technology and Nutrition, National Research Council (ICTAN-CSIC)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Obesity (BMI = 30-40 kg/m2).

Exclusion Criteria:

• Subjects with a pharmaceutical treatment set to modify blood pressure, lipid profile or glucose.
• Subjects with diagnoses of type 2 diabetes, cardiovascular diseases or thyroid diseases.
• Values above the following ones: glucose, > 115 mg/dL; triglycerides, > 350 mg/dL; total cholesterol, > 280 mg/dL; systolic blood pressure, > 150 mmHg; diastolic blood pressure, > 100 mmHg
• Previous bariatric surgery.
• Volunteers participating in other studies (currently or during last year) or weight loss plans.
• Pregnant or breastfeeding women.
• Adherence to vegetarian diets or usual consumption of dietary supplements.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 1; All subjects will receive a high-fat breakfast and a medium-fat lunch twice. They will consume together with the breakfast the placebo (PLA) the first time and grape (GRAP) the second time.	Other: Freeze-dried grape (GRAP)/Placebo (PLA); The subjects will receive, after overnight fasting, either a monodose of freeze-dried grapes (equivalent to 300 g of fresh grapes) or isocaloric placebo solved in water, together with a high-fat breakfast. Blood samples will be collected before the intake, up to 5 h after breakfast, then a medium-fat lunch will be provided and blood samples will be collected for three additional hours. A total of 10 samples will be collected: 0-30-60-120-180-240-300-330-360-420 min. Both interventions will be separated by two weeks. Subjects will be instructed not to modify their dietary habits during the development of the study, but during the 72 h before each visit they will have to restrict the intake of polyphenol-rich foods (a detailed list will be provided).
Experimental: 2; All subjects will receive a high-fat breakfast and a medium-fat lunch twice. They will consume together with the breakfast grape (GRAP) the first time and the placebo (PLA) the second time.	Other: Freeze-dried grape (GRAP)/Placebo (PLA); The subjects will receive, after overnight fasting, either a monodose of freeze-dried grapes (equivalent to 300 g of fresh grapes) or isocaloric placebo solved in water, together with a high-fat breakfast. Blood samples will be collected before the intake, up to 5 h after breakfast, then a medium-fat lunch will be provided and blood samples will be collected for three additional hours. A total of 10 samples will be collected: 0-30-60-120-180-240-300-330-360-420 min. Both interventions will be separated by two weeks. Subjects will be instructed not to modify their dietary habits during the development of the study, but during the 72 h before each visit they will have to restrict the intake of polyphenol-rich foods (a detailed list will be provided).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postprandial glucose (300-420 min)	Changes of postprandial blood glucose as result of supplementation with grapes, measured area under the curve for the period 300-420 min	Up to two months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postprandial glucose and insulin	Changes of blood glucose (0-320 min) and insulin (0-300 and 300-420 min) as result of supplementation with grapes	Up to four months
Plasma triglycerides	Changes of plasma triglycerides (0-300 and 300-420 min) as result of supplementation with grapes	Up to four months
Plasma uric acid	Changes of plasma uric acid (0-300 and 300-420 min) as result of supplementation with grapes	Up to four months
Plasma antioxidant capacity	Changes of plasma antioxidant capacity (0-300 and 300-420 min) as result of supplementation with grapes	Up to five months
Plasma viscosity	Changes of plasma viscosity (0-300 and 300-420 min) as result of supplementation with grapes.	Up to six months
Satiety	Changes of satiety (0-300 and 300-420 min) as result of supplementation with grapes.	Up to three months

Collaborators and Investigators

• Sponsor: National Research Council, Spain
• Collaborators: California Table Grape Commission
• Investigators: Principal Investigator: Jara Pérez-Jiménez, PhD, Institute of Food Science, Technology and Nutrition (ICTAN-CSIC)

Publications and helpful links

General Publications

• Garcia-Diez E, Cuesta-Hervas M, Veses-Alcobendas AM, Alonso-Gordo O, Garcia-Maldonado E, Martinez-Suarez M, Herranz B, Vaquero MP, Alvarez MD, Perez-Jimenez J. Acute supplementation with grapes in obese subjects did not affect postprandial metabolism: a randomized, double-blind, crossover clinical trial. Eur J Nutr. 2021 Aug;60(5):2671-2681. doi: 10.1007/s00394-020-02451-6. Epub 2021 Jan 2.

Study record dates

Study Major Dates

• Study Start (Actual): December 10, 2018
• Primary Completion (Actual): November 1, 2019
• Study Completion (Actual): February 15, 2020

Study Registration Dates

• First Submitted: November 13, 2018
• First Submitted That Met QC Criteria: November 13, 2018
• First Posted (Actual): November 14, 2018

Study Record Updates

• Last Update Posted (Actual): February 25, 2020
• Last Update Submitted That Met QC Criteria: February 24, 2020
• Last Verified: February 1, 2020

More Information

Terms related to this study

• Keywords: Obesity; Insulin resistance; Polyphenols; Postprandial; Grape; Second meal effect
• Additional Relevant MeSH Terms: Overnutrition; Nutrition Disorders; Overweight; Body Weight; Obesity
• Other Study ID Numbers: HRG_2018

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