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Vitis Intervention Trial in Substrate Metabolism
Sponsor: University of Alabama at Birmingham
Summary
Obesity is associated with reduced metabolic flexibility (MetFlex), the capacity to shift between carbohydrate and lipid oxidation in response to nutrient availability. Grape polyphenols (resveratrol, catechins, quercetin, epicatechin) enhance fat oxidation and mitochondrial function in laboratory and animal studies, but whole grapes, rather than purified extracts, have not been tested for acute effects on MetFlex measured directly by whole-room calorimetry paired with mitochondrial function. This study integrates whole-room indirect calorimetry with high-resolution respirometry in peripheral blood mononuclear cells (PBMCs) to determine whether whole grape polyphenols shift the postprandial respiratory exchange ratio (RER) response to a high-fat meal and alter mitochondrial respiration, and whether responses differ by adiposity phenotype (lean vs. overweight/obesity).
Official title: Acute Modulatory Role of Whole Grape Polyphenols on Room Calorimetry Derived Respiratory Exchange Ratio and Mitochondrial Function in Obesity
Key Details
Gender
All
Age Range
25 Years - 60 Years
Study Type
INTERVENTIONAL
Enrollment
20
Start Date
2026-09
Completion Date
2027-09
Last Updated
2026-09-02
Healthy Volunteers
Yes
Conditions
Interventions
Freeze-Dried Whole Grape Powder
72 g, reconstituted with water, administered once per calorimeter stay, 30 minutes before the standardized high-fat test meal. Other name: whole California table grape powder.
Placebo
Placebo Powder - 72 g matched placebo formulated to replicate the sugar, fiber, organic acid, and sensory characteristics of the grape powder without polyphenolic compounds; administered on the same schedule.