The effect of citrus flavonoid extract supplementation on anaerobic capacity in moderately trained athletes: a randomized controlled trial

Lieke E Van Iersel,Freddy J Troost,Yala R Stevens,Jose M Conchillo

doi:10.1186/s12970-020-00399-w

Lieke E Van Iersel, Freddy J Troost + Show 2 more

Open Access

https://doi.org/10.1186/s12970-020-00399-w

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Abstract

BackgroundNutritional supplementation is commonly used by athletes to improve their exercise performance. Previous studies demonstrated that citrus flavonoid extract (CFE) supplementation may be an effective strategy to improve exercise performance in male athletes. Yet, no conclusive research has been performed to investigate the effect of chronic CFE supplementation on high-intensity exercise performance under anaerobic conditions. Therefore, the aim of the study was to assess whether CFE supplementation in daily dosages of 400 and 500 mg for a period of 4 and 8 weeks improves anaerobic exercise capacity.MethodsA randomized, double-blind, placebo controlled, parallel clinical study was conducted in 92 moderately trained healthy men and women. Subjects were randomized to receive 400 mg of CFE (n = 30), 500 mg of CFE (n = 31) or placebo (n = 31) daily, for 8 consecutive weeks. The Wingate anaerobic test was used to assess anaerobic exercise capacity and power output at baseline, after 4 weeks and after 8 weeks.ResultsAfter 4 weeks supplementation, average power output significantly increased in the 400 mg group (Estimated difference [ED] = 38.2 W [18.0, 58.3]; p < 0.001; effect size [ES] = 0.27) and in the 500 mg group (ED = 21.2 W [0.91, 41.4]; p = 0.041; ES = 0.15) compared to placebo. The 5 s peak power output was also increased in the 400 mg group (ED = 53.6 [9.96, 97.2]; p = 0.017; ES = 0.25) after 4 weeks compared to placebo. After 8 weeks of supplementation, average power output was significantly improved in the group receiving 400 mg of CFE (ED = 31.6 [8.33, 54.8]; p = 0.008; ES = 0.22) compared to placebo.ConclusionThese results demonstrate that CFE supplementation improved anaerobic capacity and peak power during high intensity exercise in moderately trained individuals. Further research is needed to identify the underlying mechanisms that are affected by CFE supplementation.Trial registrationClinicalTrials.gov (NCT03044444). Registered 7 February 2017

Highlights

Nutritional supplementation is commonly used by athletes to improve their exercise performance [1]
It is considered that moderate exercise induces production of low concentrations of reactive oxygen species (ROS) in mitochondria, which subsequently act as a signal to stimulate the synthesis of enzymes that are involved in the adaptive response of the skeletal muscle, such as nitric oxide (NO) synthase and superoxide dismutase (SOD) [7,8,9]
Average power output after 4 weeks No significant differences in body weight were observed over time in the placebo and the two treatment groups

Summary

Introduction

Nutritional supplementation is commonly used by athletes to improve their exercise performance [1]. During the first 30 s of very high intensity-exercise, the phosphagen system is involved, producing immediate but limited energy under anaerobic conditions [5, 6]. Anaerobic energy expenditure increases the production of fatigue associated products, mainly lactate and high levels of ROS, which contributes to impaired muscle functioning and oxidative damage as the body’s antioxidative scavenging capacity may be exceeded [2, 5, 6]. Previous studies demonstrated that citrus flavonoid extract (CFE) supplementation may be an effective strategy to improve exercise performance in male athletes. No conclusive research has been performed to investigate the effect of chronic CFE supplementation on high-intensity exercise performance under anaerobic conditions. The aim of the study was to assess whether CFE supplementation in daily dosages of 400 and 500 mg for a period of 4 and 8 weeks improves anaerobic exercise capacity

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Conclusion