Oral vitamin C restores endothelial function during acute inflammation in young and older adults

Oxidative stress has been linked to reductions in vascular function during acute inflammation in young adults; however, the effect of acute inflammation on vascular function with aging is inconclusive. The aim of this study was to determine if oral antioxidant administration eliminates vascular dysfunction during acute inflammation in young and older adults. Brachial flow‐mediated dilation (FMD) and carotid‐femoral pulse wave velocity (PWV) were measured in nine young (3 male, 24 ± 4 yrs, 26.2 ± 4.9 kg/m2) and 16 older (13 male, 64 ± 5 yrs, 25.8 ± 3.2 kg/m2) adults before and 2‐h after oral consumption of 2 g of vitamin C. The vitamin C protocol was completed at rest and 24 h after acute inflammation was induced via the typhoid vaccine. Venous blood samples were taken to measure markers of inflammation and vitamin C. Both interleukin‐6 (Δ+0.7 ± 1.8 pg/ml) and C‐reactive protein (Δ+1.9 ± 3.1 mg/L) were increased at 24 h following the vaccine (p 0.05). FMD was lower in all groups during acute inflammation (Δ‐1.4 ± 1.9%, p 0.05). Vitamin C restored FMD back to initial values in young and older adults during acute inflammation (Δ+1.0 ± 1.8%, p 0.05). In conclusion, oral vitamin C restored endothelial function during acute inflammation in young and older adults, with no effect on aortic stiffness. The effect of vitamin C on endothelial function did not appear to be due to reductions in inflammatory markers. The exact mechanisms should be further investigated. Oral vitamin C exerts beneficial effects and restores endothelial function during acute inflammation in young and older adults. Vitamin C may therefore be a practical future therapy for reducing cardiovascular event risk in older adults during acute inflammation, perhaps due to its vascular antioxidant capacity or its possible additional ability to alter nitric oxide bioavailability by stabilizing BH4.