None of the papers you cited show any sort of negative or inverse correlation between Arterial Stiffness and Ascorbate Supplementation.
Here is one that does (FMD and blood pressure are measures of arterial stiffness):
Clin Sci (Lond). 2009 Mar;116(5):433-41. doi: 10.1042/CS20080337.Oral antioxidants and cardiovascular health in the exercise-trained and untrained elderly: a radically different outcome.AbstractBoth antioxidant supplementation and exercise training have been identified as interventions which may reduce oxidative stress and thus improve cardiovascular health, but the interaction of these interventions on arterial BP (blood pressure) and vascular function has not been studied in older humans. Thus in six older (71+/-2 years) mildly hypertensive men, arterial BP was evaluated non-invasively at rest and during small muscle mass (knee-extensor) exercise with and without a pharmacological dose of oral antioxidants (vitamins C and E, and alpha-lipoic acid).
Confounded by concomitant administration of E and alpha-lipoic acid
The literature is quite clear -- from the studies I posted earlier in this thread that Ascorbate reduces AS, and also improves vascular endothelial function
The studies you posted were for sick or menopausal presumably sedentary people. I don't think they studied any interaction of vitamin C with exercise, unless I am missing something.
My take-away from all this is that high dose vitamin C is good for vascular function in sedentary or sick people, and probably bad for vascular function in people who exercise (at least if taken within a certain period before or after exercise). For this reason, I avoid antioxidants on exercise days, but I still take them on sedentary days.
Edited by nowayout, 28 February 2015 - 02:28 PM.