In rats, higher nitrate levels in blood and saliva were linked to lower blood pressure, showing how the body's nitrate system might help control blood pressure.

When nitrite levels in the blood go up after taking nitrate supplements, blood pressure tends to go down more. The higher the nitrite increase, the bigger the blood pressure drop.

How well your mouth bacteria convert nitrate to nitrite is related to how much your blood pressure drops after eating nitrate-rich food, even when accounting for your starting blood pressure.

Even though older people with high blood pressure are already taking medicine for it, their bodies can still turn nitrates from food (like beets or spinach) into useful compounds — but this doesn’t seem to lower their blood pressure or improve their blood vessels over time.

When nitrite levels in the blood went down after using mouthwash, blood pressure went up, and this connection was strong enough to be statistically significant.

Researchers measured blood pressure and nitrate/nitrite levels in blood and saliva 2.5 hours after giving women a nitrate-rich drink.