Beetroot Juice Enhances Nitrate Metabolism and Endothelial Function but Not Cardiovascular or Strength Performance in...

Inorganic nitrate (NO₃^-) has demonstrated therapeutic efficacy in several populations characterised by cardiovascular risk. However, it is unknown whether increasing nitric oxide (NO) bioavailability affects vascular and cardiovascular responses in men with androgenic-anabolic steroid (AAS) abuse.

To investigate the effects of dietary NO₃^- on cardiovascular, autonomic, and strength performance in men with AAS abuse.

In this double-blind, randomised, placebo-controlled crossover trial, participants consumed beetroot juice (12.8 mmol [800 mg] NO₃^-) or a placebo (0.3 mmol NO₃^-). After two hours, assessments included saliva collection, endothelial function, heart rate, and systolic (SBP) and diastolic (DBP) blood pressure at rest, during, and after an isometric handgrip test.

Thirteen resistance-trained males [mean (standard deviation) age: 31 (9) y; body mass index (BMI): 30 (4) kg/m²; SBP: 132 (3) mmHg; DBP: 70 (2) mmHg] completed the protocol. NO₃^--rich juice significantly increased salivary NO₃^- (40.6 μM, p < 0.001) and nitrite (NO₂^-) (3.1 μM, p = 0.002) versus placebo. Flow-mediated dilation was greater with NO₃^- both at pre-exercise (2.37%, p = 0.02) and post-exercise (2.57%, p = 0.01). No between-group differences were observed in isometric strength (0.02 kgf, p = 0.99) or systolic/diastolic blood pressure across conditions.

Dietary NO₃^- enhanced salivary NO₂^- and NO₃^- concentrations and modestly improved endothelial function but did not reduce the elevated blood pressure or alter cardiac autonomic responses associated with AAS abuse.