Non-Hispanic black individuals have an elevated prevalence of cardiovascular disease in large part, related to impaired vascular function, secondary to reduced nitric oxide (NO) bioavailability. Nitrate supplementation increases NO bioavailability and improves vascular function. This study tested the hypothesis that forearm blood flow responses in young, non-Hispanic, black (BL) men during mental stress are blunted relative to, non-Hispanic, white (WH) men and that acute dietary nitrate supplementation would improve this response in BL men. This study was comprised of two parts. Phase 1 investigated the blood flow responses between young, BL and WH men whereas Phase 2 investigated the effect of acute nitrate supplementation in a subset of the BL men. Eleven (9 for Phase 2) BL and 8 WH men (23 ± 3 vs. 24 ± 4 y, respectively) participated. During each visit, brachial artery blood flow was assessed during 3 min of mental stress. Phase 1 was completed in one visit, while Phase 2 was completed over two visits separated by ~1-wk. During Phase 2, data were collected before and 2-h post-consumption of a beverage high in nitrate content or nitrate depleted. In Phase 1, peak forearm blood flow (FBF, P < 0.01), total FBF (P < 0.05), and forearm vascular conductance (P < 0.001) were blunted in the BL. During Phase 2, pre-beverage responses were unaffected following beverage consumption (P > 0.05 for all). Young, BL men have blunted microvascular vasodilatory responses to acute mental stress, which may not be altered following acute nitrate supplementation.
