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Study of Grape Consumption in Adaptation to Seasonal Photoperiod
Sponsor: University Rovira i Virgili
Summary
The goal of this randomized clinical trial is to learn whether consuming grapes during their natural season can help the body adapt to the shorter daylight hours of winter. The study includes men and women aged 30-70 years with either normal weight or overweight or obesity and metabolic dysfunction-associated steatotic liver disease (MASLD). The main questions it aims to answer are: * Does seasonal grape consumption change circulating microRNAs, small molecules involved in regulating gene activity? * Does grape consumption influence sleep, physical activity, metabolic markers, body composition, muscle function, and gut bacteria during the transition to winter? Within each population group, researchers will compare participants consuming yogurt with freeze-dried grape powder with participants consuming the same yogurt without grape powder. Both groups will receive the same Mediterranean-style dietary guidance. Participants will: * Consume two yogurts daily for 3 weeks, either with or without a total daily dose of 16 grams of freeze-dried grape powder, equivalent to approximately 80 grams of fresh grapes. * Complete a further 2 weeks of follow-up without the grape intervention. * Attend an initial information visit and three assessment visits for blood sampling, stool sample collection, and measurements of body composition and muscle function. * Wear a wrist device to monitor sleep and physical activity. * Complete questionnaires, dietary records, and a sleep diary.
Key Details
Gender
All
Age Range
30 Years - 70 Years
Study Type
INTERVENTIONAL
Enrollment
46
Start Date
2026-09-28
Completion Date
2026-11-06
Last Updated
2026-10-21
Healthy Volunteers
Yes
Interventions
Freeze-Dried Grape Powder
Freeze-dried Cabernet Sauvignon grape powder administered orally at a total dose of 16 g/day, equivalent to approximately 80 g of fresh grapes. The daily dose is divided into two servings, mixed with plain, low-fat yogurt without added sugar and consumed in the morning and afternoon for 3 weeks during the local grape harvest season. This is followed by 2 weeks without grape supplementation.
Plain Low-Fat Yogurt
Two daily servings of plain, low-fat yogurt without added sugar, consumed in the morning and afternoon for 3 weeks.
Mediterranean-Style Dietary Guidance
Both arms receive the same dietary guidance based on a Mediterranean dietary pattern.
Locations (1)
Hospital Universitari Joan XXIII - Unitat d'Investigació Clínica, IRB CatSud
Tarragona, Tarragona, Spain