The effect of quercetin supplementation on the responses of sirtuin-1, brain-derived neurotrophic factor and insulin-like growth factor-1 to high intensity interval exercise and continuous exercise in female athletes

Background and Purpose: Nowadays, physical exercise and using the food supplements containing flavonoids are considered as the main drivers of positive regulation of nerve growth factors and improvement of neuromuscular function. Quercetin is one of the plant flavonoids that crosses the blood-brain barrier and plays an effective role in improving brain health. The aim of this research was to investigate the effect of quercetin supplementation on the responses of sirtuin-1 (SIRT-1), brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-1 (IGF-1) to high intensity interval exercise and continuous exercise in female athletes.
Materials and Methods: This is a semi-experimental, double-blind, applied research with a pre-and post-test design. Forty female athletes from Zabol University with sports experience between one and three years (Mean±SD; age, 21.3±61.0 years; body mass index, 21.79±3.12 kg/m²) were selected and randomly divided into equal groups (n=10) including: 1) high intensity interval exercise + quercetin, 2) continuous exercise + quercetin, 3) high intensity interval exercise + placebo and 4) continuous exercise + placebo. At the beginning and at the end of 14 days, the participants performed a session of continuous exercise (at 60% of VO₂max) and an interval exercise (4 intervals of 4 minutes activity at 90% of VO₂max followed by 3 minutes recovery) and during these 14 days, the supplement and placebo groups consumed two 500 mg capsules of either quercetin or dextrose daily. Fasting blood sampls were collected at four stages, before and immediately after the first and second acute exercise (prior to and at the end of 14 days of supplementation, respectively) and analysed for measuring SIRT-1, BDNF and IGF-1 by using ELISAtechnique. Statistical analyses of the data were performed using the analysis of variance with repeated measures and Bonferroni post-hoc test.
Results: After high intensity interval and continuous exercises SIRT-1, BDNF, and IGF-1 increased significantly (P<0.001). After 14 days of quercetin consumption, the responses of SIRT-1, BDNF, and IGF-1 to acute high intensity interval and continuous exercises increased significantly (P<0.01). However, no significant differences were observed between the responses of SIRT-1 (P=0.14), BDNF (P=0.32) and IGF-1 (P=0.16) to high intensity interval and continuous exercises.
Conclusion: It seems that short-term quercetin supplementation increases the baseline levels and responses of SIRT-1, BDNF and IGF-1 indices to high intensity interval and continuous exercises in female athletes, and probably stimulate nerve growth and improve neuromuscular function, though, two types of high-intensity interval and continuous exercises did not make a difference in the response of these variables, which requires further study in this field.