Can supplementation with vitamin C and E alter physiological adaptations to strength training?

Abstract

BackgroundAntioxidant supplementation has recently been demonstrated to be a double-edged sword, because small to moderate doses of exogenous antioxidants are essential or beneficial, while high doses may have adverse effects. The adverse effects can be manifested in attenuated effects of exercise and training, as the antioxidants may shut down some redox-sensitive signaling in the exercised muscle fibers. However, conditions such as age may potentially modulate the need for antioxidant intake. Therefore, this paper describes experiments for testing the hypothesis that high dosages of vitamin C (1000 mg/day) and E (235 mg/day) have negative effects on adaptation to resistance exercise and training in young volunteers, but positive effects in older men.Methods/designWe recruited a total of 73 volunteers. The participants were randomly assigned to receiving either vitamin C and E supplementation or a placebo. The study design was double-blinded, and the participants followed an intensive training program for 10–12 weeks. Tests and measurements aimed at assessing changes in physical performance (maximal strength) and physiological characteristics (muscle mass), as well as biochemical and cellular systems and structures (e.g., cell signaling and morphology).DiscussionDietary supplements, such as vitamin C and E, are used by many people, especially athletes. The users often believe that high dosages of supplements improve health (resistance to illness and disease) and physical performance. These assumptions are, however, generally not supported in the scientific literature. On the contrary, some studies have indicated that high dosages of antioxidant supplements have negative effects on exercise-induced adaptation processes. Since this issue concerns many people and few randomized controlled trials have been conducted in humans, further studies are highly warranted.Trial registrationACTRN12614000065695

Vitamin C and E supplementation does not affect heat shock proteins or endogenous antioxidants in trained skeletal muscles during 12 weeks of strength training

“…The detailed experimental design and limitations of the present study has already been described [26]. Results on muscle mass and more strength measurements have been published previously [25].…”

Vitamin C and E supplementation alters protein signalling after a strength training session, but not muscle growth during 10 weeks of training

“…Six of the 38 participants entering the study dropped out (Paulsen et al . a ). Two participants experienced injuries unrelated to the study, and four withdrew because of a time schedule that was too busy.…”

“…This study was a double‐blinded, randomized controlled trial (Paulsen et al . a ). Tests and measurements were conducted before and after 10 weeks of heavy‐load traditional strength training at four exercise sessions per week (see below).…”

Effect of Vitamin C Supplementation on Lipid Peroxidation and Lactate Levels in Individuals Performing Exhaustion Exercise

“…Nakhostin-Roohi et al (13) have reported that single dose 1000 mg vitamin C prevented lipid peroxidation in sportsmen. Similarly, 1000 mg vitamin C supplementation has been useful affects in sportsmen (14). In clinical trials, it has been shown that vitamin C supplementation may be done by 1000 mg for 60 days at humans (15).…”