Changes in Oxidative Stress, Inflammation, and Muscle Damage Markers Following Diet and Beetroot Juice Supplementation in Elite Fencers.

Lucyna Kozłowska,Jolanta Gromadzińska,Anna Mróz,Wojciech Wąsowicz,Beata Janasik,Olga Mizera,Karolina Mikołajewska

doi:10.3390/antiox9070571

Abstract

The aim of this study was to assess the impact of diet and active substances in beetroot juice on the parameters of oxidative stress, inflammation, and muscle damage as well as on the maximum rate of oxygen uptake (VO2max) in elite fencers (10 women, 10 men). Athletes during four weeks realized dietary recommendations (ID) and, after that, diet with freeze-dried beetroot juice supplementation (ID&BEET). At baseline and after each stage, fasting antioxidants, biomarkers of oxidative stress, inflammation, and skeletal muscle damage were measured, and a VO2max test was performed. Only after ID&BEET was a significant increase of VO2max observed, and changes of this parameter were negatively related with changes of serum lactate dehydrogenase (∆LDH) activity, as well as with serum ∆β-carotene and malondialdehyde concentration (∆MDA). Additionally, positive relationships were observed between ∆β-carotene versus changes of the serum concentration of advanced oxidation protein products (∆AOPP), changes of serum glutathione peroxidase activity (∆GPx3) versus both changes of physical activity level and ∆LDH, as well as erythrocyte glutathione peroxidase activity (∆GPx1) versus ∆LDH. To summarize, we showed that long-term beetroot juice supplementation increases lipid peroxidation, and improvement of VO2max after ID&BEET seems to be dependent on LDH activity, as well as on the serum concentration of MDA and β-carotene.

Highlights

Beetroot (Beta vulgaris var. rubra) is a rich source of important phytochemical compounds such as ascorbic acid, carotenoids, phenolic acids, flavonoids [1,2,3], and a group of bioactive pigments known as betalains [4,5]
Significant changes were only observed in the mean values of the maximum rate of oxygen uptake, which was higher after ID&BEET in comparison to ID (Table 1)
Our study involved a deep analysis of the changes in oxidative stress, inflammation, and muscle damage markers, as well as of the relationship between the analyzed parameters after four weeks of implementation of dietary recommendations, and after that, four weeks of implementation of dietary recommendations with beetroot juice supplementation

Summary

Introduction

Beetroot (Beta vulgaris var. rubra) is a rich source of important phytochemical compounds such as ascorbic acid, carotenoids, phenolic acids, flavonoids [1,2,3], and a group of bioactive pigments known as betalains [4,5]. Rubra) is a rich source of important phytochemical compounds such as ascorbic acid, carotenoids, phenolic acids, flavonoids [1,2,3], and a group of bioactive pigments known as betalains [4,5]. Beetroot juice is a rich source of inorganic nitrates (NO3 - ), which are a substrate for the synthesis of nitric oxide [11]. Many studies have shown the ergogenic effect of chronic and acute supplementation of nitrate, connected to improvements in walking [18,19], running [20,21], rowing [22,23], cycling [18,24], submaximal exercise [20,25], and of tolerance to more vigorous exercise [18,20]

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