Toothpaste orange juice syndrome - Why does it taste awful after brushing your teeth?

Most dentists suggest it is better to drink orange juice first, rinse the mouth with water, then brush the teeth, since we should brush after eating or drinking rather than before.

Based on personal experience, I can tell you that drinking the orange juice prior to brushing seems to reduce the terrible taste problems considerably.

Toothpaste orange juice syndrome. Flawless advice, but where's your sense of danger?

For those of you who have never walked on the wild side, you've probably experienced a lesser version of the 'toothpaste orange juice syndrome. Perhaps you've followed a heaping portion of sweet cake with lemonade and thought that someone forgot to put sugar in the lemonade.

The toothpaste orange juice syndrome works in reverse too. We've always
found that oranges taste particularly sweet after we've eaten some gherkins.

These kinds of 'flavour synergies' can work for bad or good but aren't the same phenomenon as an actual chemical reaction.

Toothpaste contains a chemical base, such as baking soda, while orange juice and other citrus fruits contain citric acid.

The experts are not sure of whether there might be a chemical reaction that would affect the taste of orange juice so drastically.

It is cited the mint flavourings of most tooth pastes as an offender as well:

Eating a peppermint, spearmint or other mint sweet, then drinking orange juice results in the same problem. Also, most toothpaste products are formulated to prolong the mint flavour to enhance the belief in long-lasting, fresh breath.

The most likely culprit in the particularly awful toothpaste-orange juice
synergy, though, is an ingredient in all of the biggest brands of toothpaste:
paste, but also in lauryl sulfate, or SLS.

You'll find SLS not only in too so shampoo, shaving cream, soap and, ahem, concrete cleaners, engine degreasers and car wash detergents.

What do all of these products have in common?

The need for foam. SLS, a derivative of coconut oil, is a detergent foaming agent used
to break down the surface tension of water and penetrate solids while generating prodigious amounts of foam.

You know what happens to a layer of lipid when you add a detergent to it?

Well, that's what happens to your taste system same effect when you put detergent in your mouth, brushing teeth.

So you brush your teeth and the phenomenon is that your ability to taste sweet declines, and everything that should normally taste sweet, tastes as if a bitter taste has been added to it.

SLS will also affect your perception of salty foods. If you eat salty snacks such as potato crisps after brushing your teeth, the salt taste will be faint or missing.

Internet indicates that some people are concerned about its harmful properties.
Warnings around that SLS can harm the skin, the eyes, hair and immune system.