Pharmacokinetics of Nitrate and Nitrite Following Beetroot Juice Drink Consumption.

BACKGROUND

Nitrate (NO )-rich beetroot (BR) juice supplementation has been shown to improve cardiovascular function via reduction to nitrite (NO ) and then to the bioactive molecule nitric oxide (NO). However, limited research exists for the role of inorganic NO that is contained naturally within BR.

OBJECTIVE

As BR juice can naturally contain both NO and NO the objective of this study was to evaluate the individual effects of NO and NO consumed from BR on plasma [NO ]/[NO ] and their subsequent effects on various cardiovascular measures.

DESIGN

In four separate treatments, 11 healthy adults consumed 250 mL of BR containing one of the following: (i) high NO , low NO (HL; 572 mg NO , 32 mg NO ); (ii) medium NO , medium NO (MM; 280 mg NO , 237 mg NO ); (iii) low NO , medium NO (LM; 43 mg NO , 262 mg NO ); (iv) placebo (PL; low NO , low NO : 8 mg NO , 5.8 mg NO ). Plasma [NO ]/[NO ], blood pressure, heart rate, mean arterial pressure (MAP), cardiac output and stroke volume were measured at baseline and every hour or second hour for 6 h post-BR consumption.

OUTCOMES

Ingestion of the HL and MM BR increased plasma [NO ] and [NO ] after 2 h, with both remaining elevated after 6 h ( < 0.05). LM increased plasma [NO ] ( < 0.05) but did not increase plasma [NO ] compared to PL ( = 0.177). MAP was lower following the consumption of HL at 4 h and LM at 6 h ( < 0.05).

CONCLUSION

Inorganic NO consumption is the critical factor in elevating plasma [NO ] and [NO ]; however, both NO and NO show potential to reduce MAP. The known reduction of systolic blood pressure (SBP)/diastolic blood pressure (DBP) following NO supplementation was not observed, making it unclear if NO contributes to a reduction in SBP/DBP alongside NO .