Nitric oxide, not to be confused with nitrous oxide, laughing gas,

is a gase compound best known as the open sesame molecule released by our artery lining

to enable our blood vessels to dilate.

But it also has broad-spectrum antifungal, antiviral, and antibacterial properties. It's secreted into our airways as a first line of defense against respiratory infection,

shooting up by more than 500% over baseline. If you infect people with rhinovirus, the most common cause of the common cold,

you can correlate the levels of exhaled nitric oxide the body is able to generate

with the speed of symptom resolution.

How can we boost levels even higher?

By eating nitrate-rich vegetables.

To improve performance, some athletes dope with beet juice, which can also lower blood pressures

and people with hypertension, the nitrate in beets in green leafy vegetables can be converted

by the body into nitric oxide.

So can they be used to help clear infections?

Perhaps it's no coincidence that an infusion of spinach leaves

has evidently been used since ancient times to treat respiratory symptoms.

Within 45 minutes of drinking a double shot of beet juice,

nitric oxide levels in our breath go up by 80 percent and stay

elevated for at least three hours.

So researchers decided to test whether it could actually prevent infections.

Psychological stress, such as struggling through final exam week, appears to lower exhaled

nitric oxide.

But starting out with higher levels

...