Effects of proanthocyanidin on oxidative stress biomarkers and adipokines in army cadets: a placebo-controlled, double-blind study

Abstract

The relatively recent advent of polyphenol supplement for exercise studies has been tested in a variety of forms and doses. However, the dose-response on adipokines and oxidative stress biomarker effect remains unknown. The aim of the present study was to assess the effect of intense, long-duration (48-h) exercise, and a single dose of proanthocyanidin, on plasma leptin, adiponectin, and electronegative low-density lipoprotein (LDL(-)) concentrations. Fifty-four healthy male army cadets (22±2years) participated in a double-blind, randomized, placebo-controlled study and were distributed between control (CG; n=27) and supplemented groups (SG; n=27). Immediately before the start of the exercise, both CG and SG groups received a capsule containing starch (200mg) or proanthocyanidin (dry Vitis vinifera extract, 200mg), respectively. Following a 12-h fasting period, the plasma adiponectin, leptin, and LDL(-) concentrations were measured prior to the start of the exercise after 24 and 48h of military training, and after 24h of rest. The effects of the proanthocyanidin (supplement), exercise (time), and their interaction were investigated using factorial two-way ANOVA. Plasma leptin concentration was only influenced by exercise (p=0.001). Plasma adiponectin concentration was influenced by exercise (p=0.037), and by the exercise x supplement interaction (p=0.033). LDL(-) was influenced by the supplement (p=0.001), exercise (p=0.001), and their interaction (p=0.001). A single dose of proanthocyanidin (200mg) was able to reduce LDL(-) concentration and increase plasma adiponectin concentration after 24h of rest in SG group, indicating its potential protective action.