A MULTIVITAMIN-MULTIMINERAL SUPPLEMENTATION DOES NOT AFFECT ENDURANCE EXERCISE INDUCED GLUTATHIONE ALTERATIONS IN FEMALE SPORT STUDENTS

Abstract

Purpose: After stremous exercise, inducing a high oxidative stress, blood levels of reduced glutathione (GSH) are usually reduced and levels of oxidized glutathione (GSSG) are usually increased. It is not clear, whether exercise induced changes in glutathione system are affected by a multivitamin/multimineral supplementation in female sport students during the 1st semester. METHODS: 36 female sport students, age (19 ü 25 yrs) of the first semester were randomly devided into a verum group (V) and a placebo group (P), receiving a daily dosage of a multivitamin-multimineral supplementation (V) or a placebo (P), respectively. Prior to medication subjects took part in an incremental run field test (IRT) and a 2 hr endurance run (ER) (U1). Tests were repeated after 8 weeks of supplementation (U4). ER was started 24 hrs after IRT. Run velocity in ER remained constant in U4, corresponding to 60–70% of the individual 4 mmol/1 lactate threshold (v4) in U1. Venous blood samples were taken prior to and immediately after ER. GSH and GSSG were determined by HPLC. RESULTS: V4 increased significantly from U1 to U4 (3.23 ± 0.43 m/s vs. 3.44 ± 0.33 m/s) without any significant differences between V and P. GSH, GSSG and GSH/GSSG in U1 and U4 before and after ER in V, P and the total group (T) are shown in the table. Exercise-induced changes were significant for GSH (decline), GSSG (increase) and GSH/GSSG (decline) (p < 0.01). There was a significant decline in GSH and GSSG, and a significant increase in GSH/GSSG (p < 0.01) from U1 to U4. Exercise induced decline in GSH was smaller in U4, increase in GSSG was smaller in U4, and decline in GSH/GSSG was less pronounced in U4 compared to U1, respectively. There were no significant differences in resting values or exercise induced changes between V and P, respectively. CONCLUSIONS: In female sport students, a 2 hr run induces dramatic changes in blood glutathione system, indicating activation of antioxidant defense mechanisms. Although absolute exercise intensity remains the same, exercise induced decline in GSH and increase in GSSG is reduced, when aerobic fitness level gets better. Intake of a multivitamin-multimineral supplementation over several weeks does not have any further effect on glutathione system alterations.Table: No Caption Available