Abstract
This study investigated the effects of acute antioxidant supplementation on endothelial
function, exercise blood flow and oxidative stress biomarkers in 9 young African American
compared to 10 Caucasian males (25.7±1.2 years). We hypothesized that African American
males would have lower exercise blood flow and endothelial responsiveness compared
to Caucasian males, and these responses would be improved following antioxidant supplementation.
Ultrasonography was used to measure blood flow during handgrip exercise. Endothelial
function was assessed using flow-mediated dilation, and lipid peroxidation was assessed
by measuring levels of malondialdehyde-thiobarbituric acid reactive substances. African
American males exhibited lower endothelial function than Caucasians at baseline (8.3±1.7
vs. 12.2±1.7%) and the difference was ameliorated with antioxidant supplementation
(10.7±1.9% vs. 10.8±1.8%), but the interaction was not significant (p=0.10). There
were no significant changes in malondialdehyde-thiobarbituric acid reactive substances
following antioxidant supplementation. There was a significant increase in brachial
blood flow and forearm vascular conductance with exercise but no differences with
antioxidant supplementation. There were no group differences in exercise responses
and no differences with antioxidant supplementation, suggesting a lack of influence
of oxidative stress during exercise in this cohort.
Key words
endothelial function - exercise blood flow - oxidative stress - antioxidant - racial
differences - vascular
