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 500 mg per day