Have you ever sipped a fresh glass of chilled orange juice after brushing your teeth? The bad taste left in your mouth can be a real shock the first time it happens. Actually, it’s not just OJ that tastes so bad after brushing your teeth. Other seemingly innocuous foods such as strawberries and iced tea can also taste shocking after brushing your teeth.
So what causes it? There is one ingredient commonly found in most toothpastes that is responsible for the dramatic change in taste: sodium laureth sulfate. Sometimes shown on labels as sodium lauryl sulfate, SLS, or SLES, this ingredient is a surfactant included to help toothpaste foam up to cover your teeth.
Used in other products, such as body wash, for its incredible foaming abilities, sodium laureth sulfate helps make it easier to brush your teeth effectively and efficiently. Not only does the foaming action help spread the toothpaste around your mouth, it also emulsifies residue on your teeth for easier removal of debris and surface stains.
However, this foaming surfactant has a downside. Though the wonderful foaming action helps with cleaning your teeth, SLS/SLES also emulsifies the phospholipids on your tongue that help to dull bitter taste. This makes your taste buds more sensitive to bitter tastes. Not only that, but it also suppresses the taste buds that pick up sweetness, meaning that anything you eat or drink after brushing your teeth will taste extra sour or bitter.
Luckily for all of us, the off-putting effect is reduced after around 30 minutes because your saliva dilutes and washes away the leftover SLS. So remember to wait at least 30 minutes after brushing your teeth before eating or drinking anything, to avoid hacking your taste buds.