Saliva is really an underappreciated fluid. You don't pay much attention to it unless it's flying rudely out of someone's mouth. And that's a shame. Saliva kills bacteria, protects our teeth against decay, helps us speak and swallow, and contains all sorts of juicy information about us. Check out some cool facts about this fascinating fluid!
Did you know that, on average, we produce around 1-2 liters of saliva per day? That's a lot! When we sleep, however, we make much less of it than when we are awake. Because of this, more bacteria builds up in our mouths, and this leads to the dreaded dragon breath.
Yes, you heard that right. The salivary glands have a rich blood supply and, when blood flows through them, it passes through very thin capillaries, which allow water molecules and some antibodies to leak out. Why doesn't saliva look like blood? Because the capillaries' walls are just big enough for the water molecules, but they're too tiny for the bigger protein or other cellular components in blood to be able to pass through.
In 2012, a study conducted at the VSPM Research Centre in India split showed that heavy cell phone users (those who talk on their phones for more 2 hours per day) produced 26% more saliva than "casual" users. Moreover, the researchers also noticed that those who talked on the phone a lot had larger than average salivary glands. The scientists pointed out that, while this correlation doesn't necessarily imply cause-and-effect, the electromagnetic radiation coming from the cell phones may be the one that causes the glands to bulk up and generate too much saliva.
The majority of human cultures practice kissing, and even some animals like bonobos or pygmy chimps do so. Even elephants shove their trunks in each other's mouths. Why is everybody making out? As you may already know, kissing releases oxytocin, serotonin and dopamine, which all have a role in stirring up passion. But there's more! Human behavior researcher and anthropologist Helen Fisher states that men have a secret reason for loving wet kisses. It's because their saliva contains small amounts of testosterone, which, over time, increases the lady's libido and, hence, her willingness to do the nasty with them.
Introverts have a hard time interacting with others and, when they have to, their brain reacts pretty strongly. The RAS (reticular activating system) is the part of the brain that reacts to social contact. In an introvert, this system is much more active and more easily aroused than in an extrovert – so, when having to interact, the introvert's RAS sort of goes into panic mode. What does this have to do with saliva? Well, the RAS also has a second job: besides controlling social skills, it is also in charge of how much you salivate. So, because their RAS is overactive and so busy most of the times, shy people create 50% more saliva than their outgoing counterparts!
Pre-mastication – namely, pre-chewing food and then feeding it to the baby – was the standard practice among our ancestors, and it still is common today in some cultures. It may become a popular practice worldwide again, thanks to research showing that a mother's spit can improve her baby's immune system. Through pre-mastication, the traces of disease pathogens found in a mother's saliva can gear up the infant's production of antibodies, "training" the immune system to handle those pathogens later in life and also reducing the risk of developing autoimmune diseases.
Tuberculosis is a major issue in South Africa - according to The Guardian, there are around half a million new cases diagnosed every year. The government offers tuberculosis patients a monthly disability grant to help them get by, and this is where spit traffic comes in. Hoping to scam the government and get the medical grants, healthy people turn to saliva dealers and buy TB-positive sputum to hand it in at clinics as their own and prove that they're eligible for the aid.
Which of these facts about saliva impressed you the most? Do you know other interesting ones you'd like to share?
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