The effect of dietary nitrate on endothelial function and cardiovascular risk parameters in adults: a protocol for systematic review and meta-analysis

Abstract

Objective: Cardiometabolic diseases comprise a group of conditions that include obesity, endothelial dysfunction (ED), dyslipidemia, diabetes mellitus type 2, systemic arterial hypertension and cardiovascular disorders and are the leading cause of death in the world. Given its high prevalence, it becomes important to investigate the potential of bioactive compounds such as the sodium nitrate (NO3) present in vegetables and supplements in treating and preventing those conditions, once this substance has vasodilation properties, which may offer positive outcomes in cardiometabolic health. Methods: Our review will include all randomized clinical trials (RCTs) published in English, Spanish and Portuguese without publication date restrictions. The databases searched will be MEDLINE (PubMed), Web of Science, Cochrane, Scopus, EMBASE, LILACS, SciELO and the grey literature. To be eligible the studies must be performed in adults over 18y, with ingestion of NO3 in any form of administration or dosage, have a placebo group and assess endothelial function, arterial stiffness, blood pressure, lipid or glycemic profiles. The RoB2 tool will be used to evaluate the risk of bias and the GRADE system to evaluate the strength of evidence. Statistical analyses will be performed using RStudio for Windows and R package meta. Perspectives: An updated meta-analysis evaluating the outcome of dietary nitrate in the endothelial function and control of cardiovascular parameters would fulfill a gap in the literature, facilitating access to the available information, helping healthcare professionals to make more assertive decisions when treating or preventing those conditions and evaluate the necessity for further RCTs. Systematic review registration: PROSPERO registration no. CRD42024591474.