Organic grape juice intake improves functional capillary density and postocclusive reactive hyperemia in triathletes

Abstract

OBJECTIVE:The aim of this study was to evaluate the effect of organic grape juice intake on biochemical variables and microcirculatory parameters in triathlon athletes.INTRODUCTION:The physiological stress that is imposed by a strenuous sport, such as a triathlon, together with an insufficient amount of antioxidants in the diet may cause oxidative imbalance and endothelial dysfunction.METHODS:Ten adult male triathletes participated in this study. A venous blood sample was drawn before (baseline) and after 20 days of organic grape juice intake (300 ml/day). Serum insulin, plasma glucose and uric acid levels, the total content of polyphenols, and the erythrocyte superoxide dismutase activity were determined. The functional microcirculatory parameters (the functional capillary density, red blood cell velocity at baseline and peak levels, and time required to reach the peak red blood cell velocity during postocclusive reactive hyperemia after a one-min arterial occlusion) were evaluated using nailfold videocapillaroscopy.RESULTS:Compared with baseline levels, the peak levels of serum insulin (p = 0.02), plasma uric acid (p = 0.04), the functional capillary density (p = 0.003), and the red blood cell velocity (p<0.001) increased, whereas the plasma glucose level (p<0.001), erythrocyte superoxide dismutase activity (p = 0.04), and time required to reach red blood cell velocity during postocclusive reactive hyperemia (p = 0.04) decreased after organic grape juice intake.CONCLUSION:Our data showed that organic grape juice intake improved glucose homeostasis, antioxidant capacity, and microvascular function, which may be due to its high concentration of polyphenols. These results indicate that organic grape juice has a positive effect in endurance athletes.

Associations Between Dietary Patterns and Skin Microcirculation in Healthy Subjects

“…Few studies have investigated the relationships between foods or nutrients and microvascular function, 22,[31][32][33] but none has focused on the possible link of dietary patterns with capillary density and recruitment. In the present study, we investigated a healthy population free of hypertension and insulin Variable with the highest factor loading (>|0.4|) within the component.…”

“…First, several nutrients and vasoactive dietary compounds have been described to affect the microcirculation, [20][21][22] as well as large artery function and structure. 23,24 Second, the role of nutrition in the development of insulin resistance, diabetes mellitus, and hypertension is already well described, [23][24][25][26] and it might be mediated by early alterations in the microcirculation.…”

“…However, only 1 study has investigated to date the association between nutrition and capillary density. 22 Because foods are rarely eaten in isolation and because nutrient-based investigations underestimate the possible interactions between them, the evaluation of dietary patterns is an advanced method for dietary assessment because they represent the entire diet, not just a single nutrient. 27,28 Recently, a study indicated that dietary patterns are well correlated with vascular function and affect endothelial function, arterial stiffness, and peripheral resistance in various groups of healthy individuals or patients with vascular diseases.…”

Exercise and oxidative stress: Potential effects of antioxidant dietary strategies in sports

“…Some studies have shown that organically grown vegetables and fruits may contain higher levels of bioactive molecules, such as polyphenols [29]. Grapes are a source of flavonoids and resveratrol, and organic grape juice intake (300 ml/day for 20 days) may improve glucose homeostasis, antioxidant capacity and microcirculatory parameters in male elite triathletes [30]. Moreover, levels of insulin and uric acid, functional capillary density, and red blood cell velocity increased, whereas glucose levels, erythrocyte superoxide dismutase activity, and time required to reach red blood cell velocity during post-occlusive reactive hyperemia decreased after organic grape juice intake [30].…”

Alterations in Redox Homeostasis in the Elite Endurance Athlete

“…If there was any doubt over whether the athletes were elite, the authors of the articles were emailed for further clarification; in total 14 authors were emailed. The methodology of the 59 elite athlete articles were then reviewed in detail (step 5), and 33 articles were excluded from the final review because of one or more of the following: the authors did not state the training status of the subjects, or respond to requests for subject details (n = 4) [38,46,73,74]; the subjects were masters/former athletes (n = 3) [75][76][77], amateur or college level athletes (n = 3) [ [78][79][80], athletes, but not elite status (n = 4) [42,48,81,82] or navy recruits (n = 1) [83]; participants were elite, but under 18 years of age (n = 2) [84,85]; only one sampling point was included, compared with healthy control data (n = 1) [86]; less than half of the study population were elite (n = 2) [87,88]; there were insufficient measures of redox balance [89,90] (n = 2); the training volume was not indicative of elite cyclists at 90 km per week (n = 1) [91]; the studies were RCTs involving antioxidant supplementation in elite athletes (n = 10) [92][93][94][95][96][97][98][99][100][101]. In addition, the methodological qualities of the articles were checked using methodological quality assessment criteria for the observational articles to be included in the final analysis (step 6).…”