The effect of spinach supplementation on exercise-induced oxidative stress

Aim. Nutritional supplements have been very popular among athletes and individuals. Spinach is an important dietary vegetable rich in antioxidants which is commonly consumed. This study was conducted to assess the effects of chronic daily spinach supplementation on known markers of oxidative stress and muscle damage following half-marathon in well-trained healthy young men. Methods. Twenty well-trained men volunteered for this study. Participants were randomized in an open study placebo-controlled fashion into two groups: Spinach (S) (N.=10) and placebo (P) (N.=10). The participants took spinach supplementation or placebo daily for 14 days before running. Participants ran 21.1 km. The spinach supplementation was prepared at 1 g/kg body weight. Total antioxidant capacity (TAC) was determined as marker of plasma antioxidant capacity. Creatine kinase (CK) was measured as marker of muscle damage and malondialdehyde (MDA), protein carbonyl (PC) and uric acid were measured as markers of oxidative stress. Results. TAC significantly elevated after supplementation in S group (P<0.05). Acute exercise led to elevated levels of serum MDA, PC and CK (P<0.05). Spinach supplementation maintained PC, MDA, uric acid and CK at lower levels after exercise than the placebo (P<0.05). Conclusion. These results suggest that chronic daily oral supplementation of spinach has alleviating effects on known markers of oxidative stress and muscle damage following a half-marathon in well trained healthy young men.