Supplementation with grape pomace in healthy women: Changes in biochemical parameters, gut microbiota and related metabolic biomarkers

This paper reports a comprehensive pilot study of the effects of dietary supplementation with grape pomace (GP) in humans. After an initial washout period, the diet of 10 healthy women was supplemented with a dairy amount of 1.4 g of a red Grape Pomace (GP) extract (Eminol (R)) for 21 days. Among the different biochemical and immune parameters measured in plasma, a significant decrease (p < 0.05) was observed in blood fasting glucose levels after the 21-day supplementation. Overall, the GP supplementation did not lead to significant changes in faecal bacterial populations or, in general, in the content of faecal and urine phenolic metabolites. Nevertheless, significant changes (p < 0.05) were observed in the short-chain and medium-chain fatty acid profiles (SCFAs and MCFAs). Due to observed inter-individual differences it was not possible to establish a pattern on the microRNA expression profile associated to GP supplementation, however modulation of the expression of miRNA related to glucose metabolism was perceived after the intervention period.