Effects of Wine Grape Pomace Flour Used as a Dietary Supplement on Metabolic Syndrome Components

Study on the Effects of Wine Grape Pomace Flour, Used as a Dietary Supplement to Increase the Intake of Dietary Fiber and Antioxidants in Human, on Components of Metabolic Syndrome, Plasma Antioxidants, Oxidative Stress Markers and Inflammatory Markers

Lifestyle modifications, including healthy food intake, exercise, and suppression of tobacco smoking, constitute the most powerful tool to fight chronic diseases. Antioxidants and fiber, two components of Mediterranean diets, are key functional elements for healthy eating and nutrition. We prepared flour from wine grape pomace (WGPF), a rich source of antioxidant and fiber, to be used as an ingredient for functional foods and as a dietary supplement to increase the intake of dietary fiber and bioactive compounds. WGPF was obtained from red grapes (Cabernet Sauvignon variety, Chile). The byproduct of pressing crushed grapes after alcoholic fermentation was dried, grounded and stored. The purpose of this study is to determine the effects of red wine grape pomace flour intake on glycaemia, plasma lipid profile, plasma antioxidants (vitamin C and E), oxidative stress and inflammatory markers.

A 16-week longitudinal intervention study. Males, 30-65 years of age, with at least one component of metabolic syndrome, were randomly assigned to either the intervention group or the control group. At lunch, the intervention group was given 20 g of WGPF per day, which contained 10 g of dietary fiber and an antioxidant capacity of 7,258 ORAC (oxygen radical absorbance capacity) units. Both groups were asked to maintain their regular eating habits and lifestyles. Clinical evaluation, anthropometric measurements and biochemical blood analyses were done at the beginning and the end of the study.

The intervention was carried out at a heavy mining machinery company in Santiago, Chile. All employees were informed about the study and invited to participate. Initially, 47 male workers free of exclusion criteria agreed to participate. The number of participants in each group was chosen based on the variation coefficients in the evolution of total cholesterol in the intervention and in the control group, observed in a previous work (Jiménez, J.P., et al., Effects of grape antioxidant dietary fiber in cardiovascular disease risk factors. Nutrition, 2008. 24(7-8): 646-53).

Statistical analysis: Continuous variables will be shown as mean and standard deviation, while categorical variables as the number of cases and percentage. The student t-test for independent samples and the chi-square test will be used to analyze differences of means and proportions between the two groups, respectively. The student t-test for paired samples and McNemar's test will be used to analyze differences of means and proportions within each group. When appropriate, the Wilcoxon signed rank-sum test will be used to compare paired medians. All p values will be two-tailed and a value <0.05 will be considered to be statistically significant. Data processing and statistical analyses will be done with the SAS statistical software package version 9.1 for Windows.

Inclusion Criteria:

• Subject who regularly consumed an omnivorous diet.
• Subjects that had at least one of the five components of metabolic syndrome.

Exclusion Criteria:

• Subjects that were under treatment for diabetes mellitus, hypertension (> 160/100) or dyslipidemia (hypertriglyceridemia> 500 mg / dl, hypercholesterolemia> 350 mg / dl)
• Subjects who consume drugs affecting lipid profile, blood pressure, metabolism of carbohydrates or the antioxidant capacity of plasma.
• Subjects with obesity, BMI > 30
• Subjects who have had a cardiovascular event.
• Subjects with bariatric surgery
• Subjects with untreated thyroid disease, renal disease (serum creatinine> 1.5 mg / dl), active liver disease, or other rheumatic disease that could alter the measurements.
• Subjects with chronic inflammatory diseases.
• Subjects that use of supplements containing antioxidants.
• Smoking more than 5 cigarettes per day