If you have no idea why we’re pondering this question, go brush your teeth real quick and grab a drink (orange juice, iced tea, beer—anything except water). Awful, isn’t it?
So, why does toothpaste affect the taste of orange juice and other sweet breakfast (or midnight) snacks? It all boils down to what’s happening with the taste receptors on our taste buds, Guy Crosby, a nutrition professor at the Harvard T.H. Chan School of Public Health, told Live Science.
In a nutshell, a compound in toothpaste called sodium lauryl sulfate (SLS) alters the way we process certain tastes, at least temporarily.
But let’s start with how we detect different tastes. If you touch your tongue, you’ll notice that it’s covered with bumps and mini-ridges. Each of these bumps is made up of taste buds, which in turn are made up of taste receptors. Our mouthshave between 2,000 and 4,000 taste buds in total, and each taste bud has between 10 and 50 receptors. In other words, humans are well-equipped to savor different foods.
All of our taste buds help us to perceive five types of flavors: sweet, salty, sour, bitter and umami. (That last term describes savory foods, like cured meats, mushrooms and fermented cheeses.)
The act of tasting is a bit like a chemical puzzle. When we chomp into something, that food releases molecules that have certain shapes, and these shapes float around in our mouths. Each flavor of food has a unique shape, which matches up to a type of taste receptor with a corresponding shape. For instance, when the bitter molecules from our lunchtime arugula salad bind to a bitter receptor, that sends a series of neural signals to our brain announcing that we’ve tasted something bitter.
However, a compound present in most toothpastes wreaks havoc on this tango between flavor molecules and taste receptors.
During a vigorous toothbrushing, toothpaste bubbles and froths in your mouth. This happens because the paste includes that aforementioned compound, SLS, which acts as a detergent on your teeth. SLS is found in products that bubble or foam, including personal care products such as shaving cream and household cleaners like dish soap. But research has shown that SLS affects the ability of our taste receptors; it makes them more susceptible to bitter tastes and dials back how much we can taste sweet flavors.
But do not despair, the effects dissipate in a matter of minutes.
A free piece of advice here, if you can’t handle the bad taste don’t brush. Trust me, nobody will know if you don’t tell.