We all know toothpaste and orange juice don’t play well together. But why exactly? If you’ve ever wondered why your taste buds stand up in shock each time you down that tall glass of OJ having forgotten you just brushed, we’re here to help solve the mystery. So, let’s get down to it!

How Taste Happens

Believe it or not, science is still in the discovery phase of understanding exactly how taste works. After all, it’s a complicated and individual experience, and one that is affected by all manner of additional variables including temperature, consistency, nutrient makeup, smell, texture and flavor. Currently, science has identified five general tastes we can perceive: sweet, salty, bitter, sour and umami (meaty tastes). And, the last major discovery (umami) was in 1908, so clearly this is more complicated than we realize.

The Likely Culprit behind That Foul Taste

Since our understanding of taste is still developing, scientists aren’t completely in agreement as to why some foods and beverages are not pleasing to consume after brushing one’s teeth. The large majority, however, believe the culprit is sodium laureth sulfate, and its chemical brethren sodium lauryl ether sulfate and sodium lauryl sulfate. Used mainly as a foaming agent, this ingredient has the unfortunate side effect of suppressing taste receptors that tell our brain we’ve ingested something sweet, and allowing bitter tastes to be amped-up by temporarily diminishing populations of phospholipids that live on our tongue.

These phospholipids are fatty molecules that dampen our perception of bitter foods so we can consume them without being overwhelmed by their taste. When they’re reduced in number, though, with toothpaste containing sodium laureth sulfate, mildly bitter foods end up tasting even more bitter than they would normally. And, that is why science currently believes that acidic, citrus-y sweet glass of orange juice is a distasteful combo when paired with your foaming toothpaste.

How You Might Be Able To Sidestep This Nasty Combo

So, what’s a die-hard OJ-for-breakfast person to do? Well, you could wait until after you’ve eaten to brush your teeth, but you’ll want to make sure you wait at least a half-hour before doing so, to prevent acids you consume at breakfast (like that OJ!) from being driven deeper into your teeth when brushing. You could also try brushing your teeth with slightly warmer water – something some suggest may tame these side effects. Lastly, you could switch to a toothpaste that doesn’t have sodium laureth sulfate in it at all, and see how that works for you. 
 
So, experiment away, and do your part to help science make sense of this confounding problem. Then tell all your friends the result of your experiment!