I have always wondered why orange juice tastes horrible if you drink it right after brushing your teeth. I make sure I eat breakfast before I brush my teeth because drinking OJ after brushing my teeth is awful.
Toothpaste has something called Sodium Lauryl Sulphate (SLS) in it. SLS is found in 99% of toothpastes and apparently it does not do anything useful. The detergent creates a foam in your mouth that makes your teeth feel fresh and clean.
The foam that SLS creates temporarily affects your sweet taste buds. Because your sweet taste buds are essentially inactive, you only taste the bitter citric acid that is in orange juice. This is why it tastes bad when you drink it right after brushing your teeth.
A lot of toothpastes are beginning to stop using SLS because not only does it not have any positive effects, it actually has several negative effects. SLS is also found in some shampoos, causing cosmetic problems for a lot of people. The SLS in toothpastes has also been found to be responsible for giving people mouth ulcers.
SLS is a type of soap and a lot of people are starting to buy these SLS free toothpastes, the biggest reason being that there is no need for soap in your toothpaste. Some companies include SLS because it makes it cheaper to manufacture.
People have problems with SLS because it causes skin irritation, it is used in household cleaners, and it causes gingivitis and other gum diseases. While these are clearly the more significant problems with SLS in our toothpaste, it still makes my orange juice taste bad.