A 6-week supplementation with grape pomace to subjects at cardiometabolic risk ameliorates insulin sensitivity, without affecting other metabolic syndrome markers

• Published in: Food & function 2018-11, Vol.9 (11), p.6010-6019
• Main Authors: Martínez-Maqueda, Daniel, Zapatera, Belén, Gallego-Narbón, Angélica, Vaquero, M Pilar, Saura-Calixto, Fulgencio, Pérez-Jiménez, Jara
• Format: Article
• Language: English
• Subjects: Adult; Aged; Animal models; Biomarkers - blood; Blood Glucose - metabolism; Cardiovascular Diseases - prevention & control; Cholesterol - blood; Cross-Over Studies; Crossovers; Dietary fiber; Dietary Supplements; Fasting; Female; Fruit - chemistry; Glucose tolerance; Glucose Tolerance Test; Grapes; Health risks; Humans; Insulin; Insulin - blood; Insulin Resistance; Laboratory testing; Macromolecules; Male; Markers; Metabolic syndrome; Metabolic Syndrome - prevention & control; Middle Aged; Molecular weight; Nutrition Assessment; Plant Preparations - administration & dosage; Polyphenols; Polyphenols - administration & dosage; Risk; Risk Factors; Sample Size; Sensitivity; Triglycerides - blood; Vitis - chemistry; Young Adult
• ISSN: 2042-6496; 2042-650X
• DOI: 10.1039/c8fo01323c

Grape polyphenols have shown a promising role in the modulation of metabolic syndrome (MetS), mostly in animal models. However, clinical studies are scarce and they usually only consider a fraction of polyphenols, ignoring the non-extractable polyphenols (high molecular weight compounds or associated with macromolecules such as dietary fibre). This study aimed at evaluating the effect of grape pomace, rich in both extractable and non-extractable polyphenols, on markers of MetS. Fifty subjects (22 women) aged 20-65 with at least two MetS factors were randomly assigned to the product (daily dose of 8 g of dried grape pomace) or to the control group in a 6 week crossover design with a 4 week wash-out. Samples were collected at the beginning and at the end of both periods; half of the participants were subjected to an oral glucose tolerance test at the beginning and the end of the supplementation period. Grape pomace supplementation significantly improved fasting insulinaemia (p < 0.01), without affecting other cardiometabolic risk parameters. A tendency towards an improvement in postprandial insulinaemia was observed, particularly in those subjects with higher fasting insulin levels. Therefore, supplementation with grape pomace may be a strategy for improving insulin sensitivity in subjects at high cardiometabolic risk.