I finally discovered why we have bad breath every day when we wake up. Not that I was actively discovering it, because it happens to everyone so we just assume it's a normal thing without really being curious about why it happened.
In short it has to do with our saliva.
Our saliva contain one very powerful painkiller that's stronger than morphine, it's called opiorphin. We produce only a small amount of this compound though, otherwise we'd spaced out all the time!
And when we chew, we produce more saliva along with the opiorphin. Which explains why a sore throat often feels better after a meal.
More than protecting our oral cavity from too much pain, the saliva also protects our mouth from too many bad bacteria.
There's this substance called mucins in our saliva that acts like a protective net. The main role of these nets is to catch bad bacteria while the antibacterial substances in our saliva kill them off.
When we sleep however, we produce very little saliva. If we produce as much saliva during the day (1 to 1.5 liters) at night, we'll find ourselves in a wet situation every morning.
So because we produce less saliva, there goes our protective net and antibacterial substance as well. Microbes and bacteria are now free to roam and party in our mouth.
8 hours of bacteria partying is the reason why we have bad breath in the morning!
Which is why it's a good idea to brush our teeth before we sleep and after we get up in the morning.
Brushing before bedtime reduces the number of bacteria in your mouth. And brushing in the morning is like cleaning the after party.
This is one story I will tell my kids in the future :)
This post is inspired by the book Gut by Gulia Enders. If you find this topic fascinating you should check the book out.