The effect of an exogenous source of nitrate ions – beetroot powder – on blood pressure and arterial stiffness in a pilot preclinical study

Aim. Тo conduct a preclinical trial of the effect of beetroot powder (Beta-NO-BOOST), as an exogenous source of nitrate and nitrite ions (NOx), on blood pressure (BP) and arterial stiffness in patients with arterial hypertension (AH). Material and methods. The pilot preclinical study included 22 male volunteers (49±10 years) with AH who completed the protocol. Participants took Beta-NOBOOST beetroot powder, developed for the National Research Center for Therapeutic and Mechanics, at a dose of 20 g/day, equivalent to 650-700 mg NOx, orally for a week in addition to prescribed therapy. Blood pressure was monitored by 24-hour BP monitoring and volumetric sphygmography, which included measuring blood pressure in all four limbs and calculating the cardio-ankle vascular index (CAVI) and ankle-brachial index before and after beetroot powder intake. Blood was collected to analyze the total concentration of nitrate and nitrite ions (NOx, μM) using a colorimetric method based on the Griess reaction with single-step reduction of nitrate to nitrite using a vanadium (III) chloride solution in 1N hydrochloric acid. Results. Serum NOx concentrations increased by an average of 2.7 times after completing the Beta-NO-BOOST beetroot powder regimen, confirming adherence to the study protocol. No significant difference in BP levels was observed before and after Beta-NO-BOOST, but a significant decrease of 0.3 units in the arterial stiffness index (CAVI) was noted. Furthermore, after a week of Beta-NO-BOOST regimen, negative correlations were found between NOx concentrations and blood pressure parameters, with a high r coefficient reaching -0.66. Conclusion. This preclinical trial demonstrated that increased NOx concentrations in the blood were associated with decreased arterial stiffness. Based on the significant negative correlations between serum NOx levels and blood pressure, it is demonstrated that the NOx in beetroot powder contributes to lowering blood pressure. The results of the preclinical trial support the feasibility of a randomized crossover controlled clinical trial of the developed beetroot powder, Beta-NO-BOOST, as a therapeutic nutritional supplement for patients with AH.