Antibacterial mouthwash blunts oral nitrate reduction and increases blood pressure in treated hypertensive men and women.

BACKGROUND

Endothelial nitric oxide (NO) is fundamental to cardiovascular health. Dietary nitrate and nitrate from endothelial derived NO metabolism provides a significant contribution to the circulating NO pool through the nitrate-nitrite-NO pathway. A critical step in this pathway is the reduction of nitrate to nitrite by the oral microbiota. We aimed to assess the effects of antibacterial mouthwash use on markers of nitrate-nitrite-NO metabolism and blood pressure in treated hypertensive men and women.

METHODS

Fifteen treated hypertensive men and women (mean age 65 years) were recruited to a randomized controlled cross-over trial. The effects of 3-day use of antibacterial mouthwash on oral nitrate to nitrite reduction, salivary and plasma nitrate and nitrite, plasma cyclic guanosine monophosphate (cGMP) and systolic and diastolic blood pressure were compared to control (water).

RESULTS

Relative to control, 3-day antibacterial mouthwash use resulted in decreased oral nitrate to nitrite reduction (P = 0.02), decreased salivary nitrite (P = 0.01) and increased salivary nitrate (P < 0.001), and there was a trend toward a decrease in plasma nitrite concentration (P = 0.09). Use of antibacterial mouthwash over 3 days also resulted in higher systolic blood pressure (2.3mm Hg; 95% CI: 0.5, 4.0; P = 0.01), but not diastolic blood pressure (P = 0.4) or plasma cGMP (P = 0.7), relative to control.

CONCLUSIONS

Interruption of the nitrate-nitrite-NO pathway through the use of antibacterial mouthwash was paralleled by a small elevation of systolic blood pressure in treated hypertensive men and women.