Effects of vitamin C on oxidative stress, inflammation, muscle soreness, and strength following acute exercise: meta-analyses of randomized clinical trials.
European journal of nutrition
BACKGROUND:Vitamin C (ascorbic acid) seems to attenuate the overproduction of reactive species during and after exercises. Yet, no meta-analysis has summarized the magnitude of this effect. The objective of this study was to systematically review the effects of vitamin C supplementation on oxidative stress, inflammatory markers, damage, soreness, and the musculoskeletal functionality after a single bout of exercise. METHODS:Major electronic databases were searched, from inception to September 2019, for placebo-controlled randomized clinical trials (RCTs) that evaluated the effects of vitamin C supplementation on oxidative stress parameters, inflammation markers, muscle damage, muscle soreness, and muscle functionality after a single bout of exercise in healthy volunteers. Random-effects modelling was used to compare mean changes from pre- to postexercise in participants that were supplemented with vitamin C versus placebo. Data were reported as standard mean difference (SMD) and 95% confidence interval (CI). RESULTS:A total of 18 RCTs, accounting for 313 participants (62% males, median age = 24 years) were included. Vitamin C supplementation reduced lipid peroxidation immediately (SMD = - 0.488; 95% CI = - 0.888 to - 0.088), 1 h (SMD = - 0.521; 95% CI = - 0.911 to - 0.131) and between 1 and 2 h (SMD = - 0.449; 95% CI = - 0.772 to - 0.126) following exercise. Exercise induced interleukin-6 (IL-6) response was attenuated 2 h (SMD = - 0.764; 95% CI = - 1.279 to - 0.248) and between 1 and 2 h (SMD = - 0.447; 95% CI = - 0.828 to - 0.065) after exercise. No effects of vitamin C supplementation were found on creatine kinase (CK), C-reactive protein (CRP), cortisol levels, muscle soreness, and muscle strength. CONCLUSION:Vitamin C supplementation attenuates the oxidative stress (lipid peroxidation) and inflammatory response (IL-6) to a single bout of exercise. REGISTRATION:PROSPERO (CRD42018094222).
10.1007/s00394-020-02215-2
Vitamin C deficiency causes muscle atrophy and a deterioration in physical performance.
Scientific reports
L-Ascorbic acid (AsA) is a water-soluble antioxidant. We examined the effect of AsA deficiency on skeletal muscle using senescence marker protein-30 (SMP30)-knockout (KO) mice that are defective in AsA biosynthesis, which makes this mouse model similar to humans, to clarify the function of AsA in skeletal muscle. Eight-week-old female SMP30-KO mice were divided into the following two groups: an AsA-sufficient group [AsA(+)] that was administered 1.5 g/L AsA and an AsA-deficient group [AsA(-)] that was administered tap (AsA-free) water. At 4 weeks, the AsA content in the gastrocnemius muscle of AsA(-) mice was 0.7% compared to that in the gastrocnemius muscle of AsA(+) mice. Significantly lower weights of all muscles were observed in AsA(-) mice than those in AsA(+) mice at 12 and 16 weeks. The cross-sectional area of the soleus was significantly smaller in AsA(-) mice at 16 weeks than that in AsA(+) mice. The physical performance of AsA(-) mice was significantly less than that of AsA(+) mice at 12 weeks. Following AsA deficiency for 12 weeks, the expression of ubiquitin ligases, such as atrogin1/muscle atrophy F-box (MAFbx) and muscle RING-finger protein 1 (MuRF1), was upregulated. Furthermore, all detected effects of AsA deficiency on muscles of the AsA(-) group at 12 weeks were restored following AsA supplementation for 12 weeks. Thus, longer-term AsA deficiency is associated with muscle wasting, that this can be reversed by restoring AsA levels.
10.1038/s41598-019-41229-7
Vitamin C Promotes Muscle Development Mediated by the Interaction of CSRP3 with MyoD and MyoG.
Journal of agricultural and food chemistry
Previous studies have reported that vitamin C (VC), an essential nutrient, exerts beneficial effects on muscle health. However, the molecular mechanism involved in the VC-mediated regulation of muscle development is still unclear. The roles of VC in muscle development and the underlying molecular mechanisms were examined using cell and molecular biology, transcriptomics, proteomics, and animal experiments in this study. VC upregulated the expression of sodium-dependent vitamin C transporter 2 (SVCT2) and cysteine rich protein 3 (CSRP3). Additionally, VC promoted the differentiation of C2C12 cells and the repair of mouse muscle injury by upregulating the nuclear translocation of CSRP3, which subsequently interacted with MyoD and MyoG. This study provided a theoretical basis for elucidating the mechanism underlying the VC-mediated regulation of muscle development, as well as for developing animal nutritional supplements and therapeutic drugs for muscle diseases.
10.1021/acs.jafc.2c02432
Collagen and Vitamin C Supplementation Increases Lower Limb Rate of Force Development.
International journal of sport nutrition and exercise metabolism
BACKGROUND:Exercise and vitamin C-enriched collagen supplementation increase collagen synthesis, potentially increasing matrix density, stiffness, and force transfer. PURPOSE:To determine whether vitamin C-enriched collagen (hydrolyzed collagen [HC] + C) supplementation improves rate of force development (RFD) alongside a strength training program. METHODS:Using a double-blinded parallel design, over 3 weeks, healthy male athletes (n = 50, 18-25 years) were randomly assigned to the intervention (HC + C; 20 g HC + 50 mg vitamin C) or placebo (20 g maltodextrin). Supplements were ingested daily 60 min prior to training. Athletes completed the same targeted maximal muscle power training program. Maximal isometric squats, countermovement jumps, and squat jumps were performed on a force plate at the same time each testing day (baseline, Tests 1, 2, and 3) to measure RFD and maximal force development. Mixed-model analysis of variance compared performance variables across the study timeline, whereas t tests were used to compare the change between baseline and Test 3. RESULTS:Over 3 weeks, maximal RFD in the HC + C group returned to baseline, whereas the placebo group remained depressed (p = .18). While both groups showed a decrease in RFD through Test 2, only the treatment group recovered RFD to baseline by Test 3 (p = .036). In the HC + C group, change in countermovement jumps eccentric deceleration impulse (p = .008) and eccentric deceleration RFD (p = .04) was improved. A strong trend was observed for lower limb stiffness assessed in the countermovement jumps (p = .08). No difference was observed in maximal force or squat jump parameters. CONCLUSION:The HC + C supplementation improved RFD in the squat and countermovement jump alongside training.
10.1123/ijsnem.2020-0313
The Pharmacokinetics of Vitamin C.
Lykkesfeldt Jens,Tveden-Nyborg Pernille
Nutrients
The pharmacokinetics of vitamin C (vitC) is indeed complex. Regulated primarily by a family of saturable sodium dependent vitC transporters (SVCTs), the absorption and elimination are highly dose-dependent. Moreover, the tissue specific expression levels and subtypes of these SVCTs result in a compartmentalized distribution pattern with a diverse range of organ concentrations of vitC at homeostasis ranging from about 0.2 mM in the muscle and heart, and up to 10 mM in the brain and adrenal gland. The homeostasis of vitC is influenced by several factors, including genetic polymorphisms and environmental and lifestyle factors such as smoking and diet, as well as diseases. Going from physiological to pharmacological doses, vitC pharmacokinetics change from zero to first order, rendering the precise calculation of dosing regimens in, for example, cancer and sepsis treatment possible. Unfortunately, the complex pharmacokinetics of vitC has often been overlooked in the design of intervention studies, giving rise to misinterpretations and erroneous conclusions. The present review outlines the diverse aspects of vitC pharmacokinetics and examines how they affect vitC homeostasis under a variety of conditions.
10.3390/nu11102412
Vitamin C Supplementation and Athletic Performance: A Review.
Current sports medicine reports
ABSTRACT:Many athletes utilize high-dose vitamin C supplementation to optimize athletic performance. A review of research over the past 10 years on the use of vitamin C and athletic performance show mixed results. Fourteen randomized control trials were reviewed. In most studies, vitamin C was used with at least one additional supplement, usually vitamin E. Three studies showed positive outcomes associated with decreased markers of muscle damage after intense exercise with some form of vitamin C supplementation. The remaining 11 articles showed either neutral or negative effects of high dose vitamin C supplementation on muscle damage, physical performance, perceived muscle soreness, and/or adaptations to training. Based on a lack of consistent data and potential for blunted physiologic adaptations to training, long-term high-dosage supplementation with vitamin C is not recommended. Athletes should obtain antioxidants through a nutrient-rich diet instead of through supplement use.
10.1249/JSR.0000000000001083