Abstract
Objective. To investigate the effects of vitamin C (VC) supplementation on the alterations in systemic markers of inflammation as a result of participation in a 90 km down run from Pietermaritzburg to Durban in 29 subjects who completed the 1999 Comrades Marathon. Interventions. Runners were divided into groups receiving 500 mg/day VC (VC500; N = 10), 1 500 mg/day VC (VC1500; N = 12) or placebo (P, N = 7) for 7 days before the race, on the day of the race, and for 2 days following completion. Main outcome measures. Each subject recorded dietary intake before, during and after the race and provided 35 ml blood samples 15 - 18 hours before the race, immediately post race, 24 hours post race and 48 hours post race. These were analysed for full blood count, vitamins A, C and E, glucose, C-reactive protein (CRP), amyloid A, interleukin-6 (IL-6) and interleukin-8 (IL-8) concentrations. All post race concentrations were adjusted for plasma volume changes. Results. Analyses of dietary intakes and blood glucose and anti-oxidant status on the day preceding the race and the day of the race excluded carbohydrate intake or plasma vitamins E and A as significant confounders in the study. Mean pre-race concentrations of serum vitamin C in VC500 and VC1500 groups (128 – 10.2 and 153 – 10.2 mol/l) were significantly higher (p < 0.01) than in the P group (83 – 10.8 mol/l) and confirmed the additional dietary VC intake of both groups. Serum CRP concentrations were significantly higher (p < 0.05) in the VC500 group than in the VC1500 and P groups. This finding was supported by similar trends in serum amyloid A, plasma IL-6 and IL-8. When the data from the two VC groups were pooled and the vitamin intake in the placebo (N = 7) and VC (N = 22) groups compared, CRP concentrations in the VC groups were significantly higher at each of the post-race time points (p < 0.05). Conclusion. These data confirm previous findings of a trend towards an enhanced pro-inflammatory response following VC intake ≥500 mg per day. South African Sports Medicine Vol.17(1) 2005: 4-10
Highlights
As the evidence regarding the effect of vitamin C (VC) supplementation on systemic markers of inflammation following eccentric exercise is presently conflicting showing either no effect,[10,11,14] an attenuation[2,19] or evidence of an increased proinflammatory response,[5,15] it was the purpose of this study to reinvestigate and extend on our previous study on the effect of oral VC supplementation on markers of the acute phase response and muscle damage following ultramarathon running in a more extensive work
VC was extracted from the serum using 20% trichloracetic acid and assayed using the 2,4-dinitrophenylhydrazine colorimetric method (Sigma Chemical Co., St Louis, MO, USA), while plasma concentrations of vitamins A and E were determined using standard high-performance liquid chromatography (HPLC) procedures following repeated (x3) extraction with hexane and using vitamin A-acetate as the internal standard.[4]
There were no significant differences between the three groups with regard to age, height, mass, body mass index, training status, and time taken to complete the ultramarathon
Summary
It is well established that prolonged exercise results in delayed-onset muscle soreness (DOMS) which peaks after 24 - 48 hours and subsides after 5 - 7 days.[8]. The damage has been shown to be further exacerbated when the eccentric component of contraction is increased, as occurs during downhill long-distance running when muscles are used in a braking motion.[17,18,20]. As the evidence regarding the effect of vitamin C (VC) supplementation on systemic markers of inflammation following eccentric exercise is presently conflicting showing either no effect,[10,11,14] an attenuation[2,19] or evidence of an increased proinflammatory response,[5,15] it was the purpose of this study to reinvestigate and extend on our previous study on the effect of oral VC supplementation on markers of the acute phase response and muscle damage following ultramarathon running in a more extensive work. We undertook to examine the effects of supplementation using higher and lower dosages of VC in the same event 2 years later
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