Inter-individual variability in redox and performance responses after antioxidant supplementation: A randomized...

Area of Science:

• Exercise Physiology
• Nutritional Biochemistry
• Human Performance

Background:

• Antioxidant deficiency can impact physiological responses.
• Inter-individual variability in response to supplementation is not well understood.

Purpose of the Study:

• To investigate variability in redox and physiological responses to antioxidant supplementation in vitamin C-deficient individuals.
• To compare responses between low vitamin C and control groups.

Main Methods:

• Two hundred individuals were stratified by plasma vitamin C levels.
• A low vitamin C group underwent a 30-day randomized, double-blind, crossover trial with vitamin C or placebo.
• Oxidative stress markers (F2-isoprostanes) and performance metrics (VO2max, isometric peak torque) were assessed.

Main Results:

• Low vitamin C group showed higher oxidative stress and impaired performance compared to controls.
• Supplementation significantly improved vitamin C levels, reduced oxidative stress, and enhanced VO2max and isometric peak torque.
• Significant inter-individual variability in responses was observed, exceeding minimal clinically important differences for VO2max.

Conclusions:

• While most participants benefited from vitamin C supplementation, a subset did not respond.
• Results highlight the need for personalized nutritional strategies in exercise physiology.
• Individual variability in response underscores the importance of tailored interventions for optimizing athletic performance and health.