Chapter 1: The Wonders of Saliva

Saliva, often referred to by various names such as spit, drool, or slaver, might evoke thoughts of a whimsical spell from a fantasy tale. However, these terms actually trace back to the Latin word for spittle, with origins in Proto-Italic, meaning “dirty yellow” and “dirty gray.” While that description may seem unappealing, it provides insight into historical oral hygiene practices.

Despite its current clear appearance, saliva is not devoid of microorganisms. Each mouth can harbor 20 to 30 different species from a total of 700 possible microbes. The food we consume also brings additional bacteria into the mix. In fact, at any moment, billions of bacteria coexist within our mouths, thriving in a harmonious biofilm—an even larger population if dental hygiene has been neglected. Saliva’s composition, comprising 99% water, creates a moist environment conducive to this microbiome.

On a typical day, we produce about 1 to 2 liters of saliva, which is roughly equivalent to a bottle of wine. However, this doesn't mean it's a reliable source of hydration since most saliva is reabsorbed through swallowing. Interestingly, the quantity of saliva we produce fluctuates based on various emotional states. For instance, we tend to produce more saliva when happy compared to when we’re sad—who knew that drooling could be a sign of joy? Conversely, stress can lead to a decrease in saliva production. Body position also plays a role; standing tends to increase saliva production compared to lying down, as does exposure to bright light. So, the next time you experience dry mouth, consider taking a stroll in the sun with a smile; it might just help alleviate the dryness.

Saliva boasts remarkable healing properties, thanks to its high concentration of white blood cells known as neutrophils and a specific protein called histatin. Research has shown that histatin can eliminate bacteria, and when human saliva is applied to wounded cells, these cells can repair themselves. This is likely why many animals instinctively lick their wounds—perhaps humans should consider doing the same.

In contrast, insufficient saliva production can lead to painful, cracked gums. This condition can allow bacteria to settle into these crevices, potentially entering the bloodstream and causing issues in other body areas. Studies have linked gum disease to conditions such as rheumatoid arthritis, pneumonia, hepatitis, heart disease, and esophageal cancer. Additionally, a dry mouth filled with food debris can contribute to unpleasant breath. Contrary to popular belief, alcohol-based mouthwash may not be the solution, as while it eliminates some bacteria, it can also dry out the mouth, exacerbating bad breath over time.

Saliva is primarily produced by three types of glands. The parotid glands, the largest, are located just in front of the ears and can swell during mumps. The submandibular glands resemble small eggs and are situated beneath the jaw, often mistaken for lymph nodes. The tiny sublingual gland goes unnoticed but plays a vital role, alongside hundreds of even smaller minor salivary glands scattered throughout the mouth. These glands work together to generate sufficient saliva to moisten food, transforming it into a slippery bolus for easier swallowing.

When it comes to taste, saliva is indispensable; without it, food would lack flavor, tasting akin to cardboard. Saliva contains proteins that bond with taste receptors, enhancing flavors. Fascinatingly, these proteins can adapt, making foods we initially dislike more palatable over time. This phenomenon exemplifies the concept of acquired taste—there may be hope yet for broccoli and Brussels sprouts!

Moreover, saliva contains enzymes with unique properties, with amylase being the most prominent. Amylase initiates the breakdown of carbohydrates, kickstarting digestion. Other enzymes present in saliva can even aid in removing blood stains, although this is effective only when the spitter is also the bleeder.

A notable component of saliva is opiorphin, a natural painkiller that is six times more potent than morphine. Current research is exploring the development of new, non-addictive pain relief options utilizing opiorphin. Until then, sharing saliva with a loved one remains a time-honored remedy for pain.

Chapter 2: The Social Aspects of Saliva

Exploring the many surprising uses of saliva, including its healing properties and social implications, can reveal just how fascinating this bodily fluid is.

The second video title is "Importance of Saliva - YouTube," which delves into the essential roles saliva plays in our daily lives and health.

Kissing, a popular expression of affection, is laden with significance. Each time lips meet, the love hormone oxytocin is released. Additionally, there's a complex exchange of chemical signals through saliva. Research indicates that during a kiss, men transfer testosterone via their saliva, which can enhance their partner's arousal. Deep kissing, in turn, stimulates increased saliva production. Thus, the wetter the kiss, the more testosterone is exchanged, potentially leading to more intimate moments.

However, saliva isn't without its risks. A study revealed that during a ten-second French kiss, around 80 million bacteria are swapped. Unfortunately, this exchange can also include viruses such as Epstein Barr, which is responsible for mononucleosis, herpes, and Hepatitis B. To minimize the risk of exchanging unwanted germs, it's wise to avoid kissing when either partner is ill or displaying cold sores. Yet, in the heat of the moment, it can be easy to forget these precautions. While contracting an infection may be frustrating, understanding the value of saliva reminds us not to waste this precious resource.