| Effect | Increase |
| Values | FVR (a.u.). Control group: before 36.0 ± 13.9, after 56.6 ± 21.5. Vitamin C: before 39.5 ± 15.5, after 46.3 ± 18.20 |
| Trial Design | Randomized trial |
| Trial Length | 24 hours |
| Number of Subjects | 9 |
| Sex | Male |
| Age Range | 18-29, 30-44 |
In a randomized, double-blind, placebo-controlled cross-over trial, 9 healthy, male participants were tested on two separate occasions 2-3 weeks apart. The effect of an acute dose of 2 g of vitamin C or placebo administered intravenously was tested under artificial hyperglycemia, achieved through intravenous dextrose to maintain blood glucose of 14 mmol/L, while basal insulin levels were maintained by intravenous octreotide. Forearm blood flow was measured in response to infusions of acetylcholine (for endothelium-dependent vasodilation), and sodium nitroprusside (or endothelium-independent vasodilation).
Vitamin C led to a notable, statistically significant attenuation of the increase in mean arterial pressure and forearm vascular resistance and the reduction in forearm blood flow due to hyperglycemia. Endothelial function was impaired by hyperglycemia in the placebo group but the change was completely abolished in the vitamin C group.
*Glucose and insulin measures excluded due to artificial stabilization in the lab.
