Galleano M, Pechanova O, Fraga CG. Hypertension, nitric oxide, oxidants, and dietary plant polyphenols. Curr Pharm Biotechnol. 2010 Dec;11(8):837-48. doi: 10.2174/138920110793262114. PMID: 20874688.

Our review pointed to the fact that  even data are not definitive and many questions remain open, the whole evidence is encouraging to start considering diets that can provide a benefit to hypertensive subjects, and those benefits will be more significant in people that do not have controlled his/her elevated blood pressure.

https://pubmed.ncbi.nlm.nih.gov/20874688/