Grape Pomace as a Cardiometabolic Health-Promoting Ingredient: Activity in the Intestinal Environment

Abstract

Grape pomace (GP) is a winemaking by-product particularly rich in (poly)phenols and dietary fiber, which are the main active compounds responsible for its health-promoting effects. These components and their metabolites generated at the intestinal level have been shown to play an important role in promoting health locally and systemically. This review focuses on the potential bioactivities of GP in the intestinal environment, which is the primary site of interaction for food components and their biological activities. These mechanisms include (i) regulation of nutrient digestion and absorption (GP has been shown to inhibit enzymes such as α-amylase and α-glucosidase, protease, and lipase, which can help to reduce blood glucose and lipid levels, and to modulate the expression of intestinal transporters, which can also help to regulate nutrient absorption); (ii) modulation of gut hormone levels and satiety (GP stimulates GLP-1, PYY, CCK, ghrelin, and GIP release, which can help to regulate appetite and satiety); (iii) reinforcement of gut morphology (including the crypt-villi structures, which can improve nutrient absorption and protect against intestinal damage); (iv) protection of intestinal barrier integrity (through tight junctions and paracellular transport); (v) modulation of inflammation and oxidative stress triggered by NF-kB and Nrf2 signaling pathways; and (vi) impact on gut microbiota composition and functionality (leading to increased production of SCFAs and decreased production of LPS). The overall effect of GP within the gut environment reinforces the intestinal function as the first line of defense against multiple disorders, including those impacting cardiometabolic health. Future research on GP’s health-promoting properties should consider connections between the gut and other organs, including the gut-heart axis, gut-brain axis, gut-skin axis, and oral-gut axis. Further exploration of these connections, including more human studies, will solidify GP’s role as a cardiometabolic health-promoting ingredient and contribute to the prevention and management of cardiovascular diseases.

Gut Microbiota Modulators Based on Polyphenols Extracted from Winery By-Products and Their Applications in the Nutraceutical Industry

“…It is essential to mention that, during their gastrointestinal transit, polyphenols from food or dietary supplements are transformed into structurally different phenolic forms compared with intake compounds [ 8 ]. Many studies indicate that unabsorbed polyphenols (90–95% of polyphenol intake) reach the large intestine and interfere with the GM, which modifies the microflora community’s composition and functioning, generates various microbial metabolites, and influences intestinal homeostasis [ 3 , 4 , 7 , 11 ]. In the colon, polyphenolic compounds enhance the abundance of specific bacterial groups acting as prebiotics while inhibiting others based on their antimicrobial potential.…”

“…and Bifidobacterium spp., which improve gut barrier protection, or Faecalibacterium prausnitzii and Roseburia spp., which are associated with an anti-inflammatory effect [ 13 , 14 , 15 , 16 , 17 ]. At the same time, pathobionts (e.g., Escherichia coli , Enterobacter cloacae , and Clostridium ) and food pathogen species are dominant [ 11 , 17 , 18 ]. At the molecular level, food polyphenols have been reported to interfere with bacterial cell-to-cell communication (quorum sensing) and affect the cell membrane permeability of pathogens, which are important features that help fight against pathogen infection [ 19 ].…”

“…Thus, the microbial symbionts increase the energy and nutrient extraction from diet and influence the host’s signaling pathways [ 7 ]. The primary phenolic microbial-derived metabolites from winery waste polyphenols are benzoic, phenylpropionic, phenylacetic, and hippuric acids [ 11 , 14 ]. However, the number of bacterial strains isolated on culture media and capable of using polyphenols as natural substrates is low [ 19 ].…”

“…The relationship between polyphenols and the GM is influenced by the GM composition, type, and quantity of polyphenol molecules involved in this interaction. Therefore, long-term treatments seem beneficial [ 10 , 11 , 14 ]. A remarkable and consistent amount of experimental data have powerfully demonstrated the role of the GM as a critical component in understanding the beneficial health effects of dietary polyphenols.…”

“…However, only a few works have focused on the effect of grapevine residues on GM composition and the microbial metabolic profile, and even fewer show the correlation between GM changes and the health effects reported. Recently, works uncovered the modulator effects of grape pomace, considered the main agro-waste used in the formulation of functional additives in feedingstuffs, dietary supplements, and fortified foods [ 3 , 10 , 11 ]. Therefore, this study aimed to review and update the research on microbiota modulation using polyphenol-rich extracts and diets supplemented with winery by-products (grape pomace and seeds).…”