As Many Exceptions As Rules: Cats Don’t Taste Sweet, But Dogs Taste Salty

Biology concepts – gustatory sense, taste receptors, supertasters

We have discussed recently the reasons organisms taste their food are related to nutritional needs (sweet, umami, salt, fat) and protection from toxins (sour, bitter).

Sweet is the exceptional case here because it’s the only taste that works across a great range of concentrations. You can sense low levels of sugar, and it just gets sweeter as more sugar is added. For sour, too much is not a great thing – think sour patch kids. And bitter? India pale ales have way too much hops for me.

The idea that sugar is sweet across all concentrations is challenged anecdotally by Glucola.

This is a drink with 50grams of glucose. It is used to test for diabetes, especially gestational diabetes. Many people claim it is too sweet,nectar of the devil they call it. My wife, on the otherhand, asks for more. This is an amazing preventative measure in organisms – remember that Paracelsus said that only the dose makes the poison – too much of a good thing can be bad – too much protein leads to hyperaminoacidemia and hyperammonemia (too much amino acid and ammonia in blood). Too much salt can throw ionic balance out of whack, and very bitter tastes suggest a toxin. But too much sweet, no way! Evolution decided there is no such thing as too much sugar – the body wants as much energy (carbohydrate) as it can get.

Source: As Many Exceptions As Rules: Cats Don’t Taste Sweet, But Dogs Taste Salty