A Moment of Science

Spitting Image of Health

Saliva doesn't just help with digestion; it also aids your body's fight against disease and infection.

A water fountain shoots a stream of water from a human face.

Photo: John Piercy (Flickr)

Fountain face has a spit-take after hearing about saliva's health benefits.

Saliva to the Rescue

Spit happens: Healthy people produce between two and four pints of saliva per day. And that spit also happens to be very useful.

Saliva is not just a stew of water and germs. Though 94 percent water, it also contains mucus, salts, lipids, sugars, digestive enzymes, and proteins. And these proteins are diverse and do many jobs to keep your body in tip-top shape. They fight tooth decay, keep your digestive enzymes from breaking down the inner lining of your mouth, and help fight off germs.

Senior Spitizens

Saliva’s disease-fighting ability varies according to one’s age. When it comes to warding off the flu, older people’s spit may be the most effective, according to scientists from the Chinese Academy of Agricultural Science, Shaanxi Provincial People’s Hospital, and Northwest University in China.

Studying the saliva of 180 men and women of all ages, researchers found that specific glycoproteins in older people dealt with the bird flu virus differently than those in the younger set. Glycoprotein is a type of protein that acts as a lubricant and a protective agent in the mouth. The saliva proteins of people older than 65 were better at grabbing onto flu viruses than that of kids and younger adults, which may be the reason the seniors did not get infected.

This knowledge may lead to future tests that can tell someone’s state of health based on the contents of his or her spit.

Spit helps keep you healthy, but it can also spread germs from person to person. So keep your spit where it will do you the most good: in your mouth.

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