Postprandial Metabolic and Oxidative Stress Responses to Grape Pomace Extract in Healthy Normal and Overweight/Obese Women: A Randomized, Double-Blind, Placebo-Controlled Crossover Study

Abstract

Postprandial oxidative stress has been shown to promote atherosclerosis. Grape pomace (GP) is a source of similar-to-wine bioactive micro-constituents with known antioxidant properties. The aim of the present study was to evaluate metabolic and oxidative stress responses after the intake of grape pomace (GP) extract along with a high-fat meal, in normal and overweight healthy women. In a randomized, double-blind, placebo-controlled crossover study, 18 women were finally included, 11 with BMI < 25 kg/m2 and 7 with BMI > 25 kg/m2, and consumed a high-fat meal with placebo or GP extract capsules in two separate visits. Blood samples were collected before and 6 h after the consumption. Measurements included basic biochemical markers, uric acid (UA), protein carbonyls (PC), thiobarbituric acid substance (TBARS) levels, as well as superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. At certain time points, the GP extract consumption in normal-weight women reduced UA, TBARS levels, and SOD activity, whereas it increased UA and reduced PC levels in overweight/obese women, compared to the placebo. GP-derived bioactive compounds may exert antioxidant actions during the postprandial state in healthy women, through different mechanisms according to their BMI status.

Winemaking: “With One Stone, Two Birds”? A Holistic Review of the Bio-Functional Compounds, Applications and Health Benefits of Wine and Wineries’ By-Products

“…Apart from the abundant phenolics, grapes, must, wine and winery by-products also contain lipid bioactive compounds, such as bioactive polar lipids and unsaturated fatty acids (UFA), with strong anti-inflammatory and antithrombotic properties, which contribute to the bio-functional activities and protective effects of grape products like wine and its by-products [1,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. In particular, some polar lipids (glycolipids and phospholipids) rich in UFA (i.e., oleic, linoleic and linolenic acids) are the most effective lipid bioactives against specific thrombo-inflammatory pathways, including those associated with PAF and thrombin [8][9][10][11].…”

“…However, grape pomace is distinguished from other food by-products due to its high content in high-value compounds such as dietary fibre, lipid bioactives, phenolics and other natural antioxidants [22,23]. Many of these bioactive compounds have been linked to several health benefits, including anti-inflammatory, cardioprotective and antidiabetic effects [10,16,17,[21][22][23].…”

Effect of Acute Consumption of Crackers Enriched with Grape Seed Flour or Barley Flour with Added β-Glucan on Biomarkers of Postprandial Glycemia, Lipidemia, and Oxidative Stress: A Crossover Study

“…Extract consumption did not change the glucose response in all participants, although there was a tendency for a time effect. Triglyceride levels were reduced but not at the significance level, demonstrating a significant time effect, whereas total, HDL-, and LDL-cholesterol post-prandial levels were similar to baseline [49].…”

Characterization of the Sideritis scardica Extract SidTea+TM and Its Effect on Physiological Profile, Metabolic Health and Redox Biomarkers in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled Study

“…Differences in the content and concentration of phenolic derivatives and flavonoids between the two Sideritis extracts ( scardica vs. euboea ) as well as the supplementation scheme applied could explain the different results between the two studies and the high efficiency of SidTea+ TM extract in upregulating antioxidant status in healthy humans. Regarding the effects of other plant-derived extracts in humans, green tea extract supplementation failed to decrease plasma F 2 -isoprostanes concentration in adult women [ 53 ], while grape pomace extract consumption (along with a high-fat meal) was effective in reducing postprandial levels of TBARS by ~10–15% in normal-weight women [ 54 ]. Future clinical studies on S. scardica extract supplementation should investigate the safety, effects and mechanisms of action of different doses (titration studies) and supplementation duration (>4 weeks) on indices of metabolism, inflammation, redox status and physical performance in different age groups and pathophysiological conditions (e.g., aging and obesity) in order to elucidate the health-promoting effects of these extracts.…”