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Racial Differences in Macrovascular and Microvascular Function Following Acute Antioxidant Supplementation
Author(s) -
Kappus Rebecca,
Shafer Brooke,
Wee Sang Ouk,
Baynard Tracy,
Haus Jacob,
Phillips Shane,
Brown Michael,
Fernhall Bo
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.803.9
Subject(s) - antioxidant , crossover study , reactive hyperemia , medicine , vitamin c , oxidative stress , placebo , endothelial dysfunction , ascorbic acid , endocrinology , nitric oxide , chemistry , vasodilation , biochemistry , food science , pathology , alternative medicine
African Americans (AA) exhibit altered endothelial function compared to Caucasians (CA), possibly due to decrements in nitric oxide bioavailability due to elevated oxidative stress (OS) in AA, suggesting the potential benefit of an antioxidant supplement in reducing OS levels and improving vascular function in AA. Purpose: To determine differences in the responses in forearm blood flow (FBF), peak blood flow following reactive hyperemia (peak FBF), and flow mediated dilation (FMD) between AA and CA with and without antioxidant supplementation. Methods: 20 AA and 25 CA (mean age = 27 years) underwent measures of FBF, peak FBF and FMD following both acute antioxidant (Vitamin C, Vitamin E and alpha lipoic acid) and placebo supplementation in a double blind, randomized, crossover designed study. Results There were no significant differences between ethnicities in FBF, peak FBF or FMD in the placebo condition. There was a significant interaction between ethnicities in peak FBF following antioxidant supplementation. AA increased peak FBF (presented in ml/100ml/min) from 21.11±1.34 to 23.05±1.34 with the antioxidant whereas CA decreased peak FBF from 24.36±1.20 to 22.38±1.20 (p=0.049). FMD% improved in both groups following antioxidant supplementation (AA: 9.64±0.88 to 10.24±0.83; CA: 8.52±0.72 to 9.74±0.74) although this was not significant. Conclusion The improvement in peak FBF in AA following antioxidant supplementation suggests a role of OS in AA microvasculature. These changes occurred independent of changes in macrovascular function, suggesting that OS alters AA microvascular function prior to any changes in macrovascular function.