Effects of vitamin C, vitamin E, zinc gluconate, and selenomethionine supplementation on muscle function and oxidative stress biomarkers in patients with facioscapulohumeral dystrophy: A double-blind randomized controlled clinical trial

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disease characterized by progressive weakness and atrophy of specific skeletal muscles. As growing evidence suggests that oxidative stress may contribute to FSHD pathology, antioxidants that might modulate or delay oxidative insults could help in maintaining FSHD muscle function. Our primary objective was to test whether oral administration of vitamin C, vitamin E, zinc gluconate, and selenomethionine could improve the physical performance of patients with FSHD. Adult patients with FSHD (n=53) were enrolled at Montpellier University Hospital (France) in a randomized, double-blind, placebo-controlled pilot clinical trial. Patients were randomly assigned to receive 500 mg vitamin C, 400 mg vitamin E, 25 mg zinc gluconate and 200 mu g selenomethionine (n=26), or matching placebo (n=27) once a day for 17 weeks. Primary outcomes were changes in the two-minute walking test (2-MWT), maximal voluntary contraction, and endurance limit time of the dominant and nondominant quadriceps (MVCQD, MVCQND, T-limQD, and T-limQND, respectively) after 17 weeks of treatment. Secondary outcomes were changes in the antioxidant status and oxidative stress markers. Although 2-MWT, MVCQ, and T-limQ were all significantly improved in the supplemented group at the end of the treatment compared to baseline, only MVCQ and TlimQ variations were significantly different between groups (MVCQD: P=0.011; MVCQND: P=0.004; T-limQD: P=0.028; T-limQND: P=0.011). Similarly, the vitamin C (P < 0.001), vitamin E as alpha-tocopherol (P < 0.001), vitamin C/vitamin E ratio (P=0.017), vitamin E gamma/alpha ratio (P=0.022) and lipid peroxides (P < 0.001) variations were significantly different between groups. In conclusion, vitamin E, vitamin C, zinc, and selenium supplementation has no significant effect on the 2-MWT, but improves MVCQ and T-limQ of both quadriceps by enhancing the antioxidant defenses and reducing oxidative stress. This trial was registered at clinicaltrials.gov (number: NCT01596803). (C) 2014 Elsevier Inc. All rights reserved.