Effects of resveratrol supplementation on nitric oxide-mediated vascular outcomes in hypertension: A systematic review.

Hypertension is associated with endothelial dysfunction and decreased nitric oxide (NO). It has been proposed that decreasing oxidative stress may help regulate blood pressure by increasing NO concentration. Therefore, the purpose of this systematic review was to determine whether the antioxidant resveratrol effects NO-mediated vascular outcomes in hypertension. A comprehensive literature search of PubMed and EBSCOhost databases was conducted using the terms: "resveratrol" and "nitric oxide or NO" and "hypertension or high blood pressure." Searches were not restricted for year of publication or study design but limited to full-text studies from scholarly, peer-reviewed journals. Ten animal studies published between 2005 and 2017 were identified. Human studies did not meet criteria and were not included. Articles were critically assessed using the Academy of Nutrition and Dietetics' Evidence Analysis Library Quality Criteria Worksheet. All studies evaluated resveratrol supplementation and at least one NO outcome measure including: circulating NO metabolites, endothelial nitric oxide synthase (eNOS) expression, eNOS phosphorylation, and eNOS uncoupling. All but one study assessed blood pressure. Nine of ten studies reported positive significant results of resveratrol supplementation on NO outcomes, and in all but one study, this was seen concomitantly with decreases in blood pressure. Resveratrol supplementation shows promise for improving NO-mediated vascular outcomes and improving blood pressure. Translation to human studies is warranted, with dose of resveratrol considered, as the human equivalency doses are not consistent amongst animal studies. Additionally, a standard battery of tests examining NO-mediated vascular outcomes is needed to ensure generalizability among studies to determine dose-duration effects.