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

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.

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.

If you eat a little more nitrate-rich food like spinach or beets each day, the amount of nitrate in your blood goes up by a predictable amount, which might help your heart by turning that nitrate into a substance that relaxes your blood vessels.

When bacteria that help convert nitrate to nitrite in the mouth are reduced, blood pressure tends to go up by a small amount (2-3.5 mmHg for systolic and 2-2.2 mmHg for diastolic).

Eating more nitrate-rich vegetables for 16 weeks doesn’t lower blood pressure or make arteries stiffer in people with early high blood pressure—so it doesn’t help these heart health markers in the short term.