The bacteria in our mouths play a key role in our health. An analysis of oral microbes from tens of thousands of people, for example, found an association between bacteria that can cause gum disease and a higher risk of oesophageal cancer.
Other studies have exposed the mechanism by which a mouth bacterium can speed the growth of colorectal tumors and shown how oral bacteria can impair respiratory health. Finally, some research has also linked gum disease with higher dementia risk.
New research zooms in on another fascinating role that oral bacteria play in our health — namely, that they help us get cardiovascular benefits from exercise.
The new paper appears in the journal Free Radical Biology and Medicine.
Nitric oxide breaks down into nitrate, explains Bescos. This process is the beginning of a circular molecular reaction, which, in the end, results in the sustained blood-pressure-lowering effects of exercise.
To find out, Bescos and team asked 23 healthy adults to participate in two acute bouts of exercise. For each of these, the participants ran on a treadmill for 30 minutes, and the researchers monitored the participants’ blood pressure for 2 hours after the exercise.
At 1, 30, 60, and 90 minutes after the run, the participants rinsed their mouths with either antibacterial mouthwash or the control substance, which was mint-flavored water. The team also collected blood and saliva samples just before exercise and 2 hours after.
The team used “a randomized, double-blind and crossover design,” meaning that neither the testers nor the participants knew who was receiving mouthwash and who was using a placebo.
The trial revealed that the placebo intervention resulted in an average reduction of 5.2 milligrams of mercury in systolic blood pressure at 1-hour post-exercise. In contrast, rinsing with antibacterial mouthwash resulted in a reduction of only 2.0 mm Hg.
The results suggest that mouthwash reduced the blood-pressure-lowering effects by more than 60% in the first hour of post-exercise recovery and canceled them completely after 2 hours.
The prevailing notion has been that the primary source of nitrite in the blood after exercise is a nitric oxide that the body creates in endothelial cells during exercise. Endothelial cells are the cells that line the inside of blood vessels.
However, the results of the new study contradict this because blood nitrite levels did not rise after exercise in the participants who had used mouthwash. Blood nitrate levels only rose after exercise when participants rinsed with the control substance.
These findings indicate that mouth bacteria are the main source of circulating nitrite, at least in the recovery period immediately after exercise.
Writer: Sakshi Gupta