Eight-week supplementation of Aronia berry extract promoted the glutathione defence system against acute aerobic exercise-induced oxidative load immediately and 30 min post-exercise in healthy adults: a double-blind, randomised controlled trial

Background: Food antioxidants have received prompt attention for controlling oxidative stress encountered in daily life. This study aimed to examine the protective effects of Aronia berry extract (ABE) supplementation on acute aerobic exercise (AAE)-induced oxidative stress in healthy subjects. Methods: We assessed a battery of antioxidant defence and oxidative stress parameters at pre-exercise, immediately post-exercise and 30 min post-exercise in healthy middle-aged adults with habitually low intakes of fruit and vegetables in an 8-week, double-blind, randomised, controlled clinical trial with two arms (n = 70). The AAE challenge model, characterised as a treadmill exercise for 30 min at 60% VO₂ maximum, was applied to load oxidative stress at the end of the study. Pearson's correlation analysis assessed the association between the changes in antioxidant defence capacities and oxidative stress levels. Results: The time–course-dependent oxidative stress was well observed in the placebo group regarding the glutathione peroxidase (GPx) activity and the reduced glutathione (GSH) availability for antioxidant defence and erythrocyte malondialdehyde, interleukin-6 and lactate levels for oxidative damage. Meanwhile, the ABE supplementation effectively strengthened the glutathione defence system by increasing GSH availability and GPx activity immediately post-exercise and 30 min post-exercise. In addition, the scatter plot and linear regression analysis revealed strong negative correlations of GSH availability with oxidised low-density lipoprotein and plasma malonaldehyde levels. Conclusion: These findings suggest that daily supplementation of 300 mg ABE might help boost GSH levels and an adaptive antioxidant enzyme defence system of erythrocytes in healthy adults with habitually low fruit and vegetable intakes.