Augmentation of the acute phase response in vitamin C-supplemented ultramarathoners

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