Effect of Muscadine Grape Seed Supplementation on Vascular Function in Subjects with or at Risk for Cardiovascular Disease: A Randomized Crossover Trial

Abstract

Background Muscadine grape seeds have high concentrations of polyphenolic compounds with antioxidant and other properties that would be expected to have favorable effects on endothelial function. Objectives To evaluate the effect of muscadine grape seed supplementation on endothelial function and cardiovascular risk factors in subjects with increased cardiovascular risk. Design In a randomized, double-blind, placebo-controlled crossover trial, 50 adults with coronary disease or ≥1 cardiac risk factor received muscadine grape seed supplementation (1300 mg daily) and placebo for 4 weeks each, with a 4-week washout. Resting brachial diameter and brachial flow-mediated dilation (FMD) and biomarkers of inflammation, lipid peroxidation, and antioxidant capacity were determined at the beginning and end of each period and compared in mixed linear models. Results There was no evidence of improved FMD (% change) with muscadine grape seed (muscadine grape seed: pre 5.2% ± 0.3%, post 4.6% ± 0.3%, p = 0.06; placebo: pre 5.3% ± 0.4%, post 5.2% ± 0.4%, p = 0.82; p for muscadine grape seed vs. placebo = 0.25). However, there was a significant increase in baseline diameter (mm) with muscadine grape seed supplementation (muscadine grape seed: pre 4.05 ± 0.09, post 4.23 ± 0.10, p = 0.002; placebo: pre 4.12 ± 0.11, post 4.12 ± 0.10, p = 0.93; p for muscadine grape seed vs. placebo = 0.026). All other biomarkers were not significantly altered by muscadine grape seed supplementation. Conclusions Four weeks of muscadine grape seed supplementation in subjects with increased cardiovascular risk did not produce a statistically significant increase in brachial flow-mediated vasodilation or a significant change in other biomarkers of inflammation, lipid peroxidation, or antioxidant capacity. However, the muscadine grape seed supplement did result in a significant increase in resting brachial diameter. The clinical significance of the effect on resting diameter is not yet established. More research is warranted to fully characterize the vascular effects of this and other grape-derived nutritional supplements and to determine whether these vascular effects translate into important clinical benefits.

Resveratrol, in its natural combination in whole grape, for health promotion and disease management

“…45 In this double-blind, randomized crossover trial, there was no evidence that 4 weeks of daily supplementation with muscadine grape seed improved endothelial function measured by brachial flow-mediated dilatation (FMD). However, there was clear evidence that this supplement produced an increase in resting brachial diameter.…”

Functional Foods for Health: The Interrelated Antioxidant and Anti-Inflammatory Role of Fruits, Vegetables, Herbs, Spices and Cocoa in Humans

“…Dietary interventions were grouped according to different categories, specifically vegetables (Table 1 ) [26-31], fruits (Table 2 ) [32-54], grape seeds (Table 3 ) [55-59], herbs (Table 4 ) [60-65], green tea (Table 5 ) [66-70], spices (Table 6 ) [71-78], beverages with mixed composition (Table 7 ) [8, 79-82] extracts with mixed composition (Table 8 ) [83-93] and cocoa products (Table 9 ) [66, 94-97]. Selection of the plant foods was performed on the basis of available human data on both oxidative and inflammatory markers: for example, raspberry, blackberry and olives were not included due to the lack of combined information.…”

Intake and time dependence of blueberry flavonoid–induced improvements in vascular function: a randomized, controlled, double-blind, crossover intervention study with mechanistic insights into biological activity

“…Indeed, although improvements in FMD have been observed in hypercholesterolemic individuals after pure anthocyanin (320 mg) ingestion (3) and in healthy individuals and individuals with the metabolic syndrome or coronary heart disease after the intake of grape polyphenols (12)(13)(14), other studies with grape or grape extracts showed no significant vascular impact (15,16). Datasets on blood pressure have also been mixed, with blueberry intake decreasing blood pressure in individuals with the metabolic syndrome (17) but not in chronic smokers (18) or obese insulin-resistant individuals (19).…”