What is a supertaster?

Remember when George H. W. Bush said he didn’t like broccoli? “I do not like broccoli and I haven’t liked it since I was a little kid and my mother made me eat it. And I’m President of the United States and I’m not going to eat any more broccoli.” Supertasters react strongly to bitter tastes: Broccoli, brussel sprouts, grapefruit juice, and unsweetened coffee. Not liking broccoli suggests Bush might be a supertaster, although by itself it’s not a definitive test.

It turns out some people are especially sensitive to certain bitter tastes. Dr. A. L. Fox, a scientist in a DuPont chemistry lab, discovered this by accident in 1931. He was working with the chemical PTC (phenylthiocarbamide) when he accidentally released a fine crystalline cloud of the powder into the air.

When another scientist in the lab, who was standing some distance away, complained about the bitter taste, Dr. Fox noticed that he didn’t taste anything. Fox took PTC to the 1931 meeting of the American Association for the Advancement of Science and, among the 2,500 attendees he tested, 28% couldn’t taste it. Sensitivity to the bitter taste of PTC turned out to be a genetically inherited trait, like eye color and blood type.

Supertasters, medium tasters, and nontasters

In the early 1990s Linda Bartoshuk, the world’s leading expert on taste, noticed that some of her research subjects reacted very strongly to PTC. Some people, in fact, find PTC so bitter it makes them nauseous. She called these people supertasters.

In sufficient quantities PTC is toxic, so it’s not ideal for taste testing. Today research scientists use a chemical relative of PTC called PROP, short for 6-n-propylthiouracil. Experimenters dissolve a small amount of PROP in water and let subjects wet their tongues. Supertasters react strongly and very negatively to the bitter taste. Those without sensitivity to PROP, called nontasters, think the water simply tastes like water. Those who detect a bitter but not necessarily objectionable taste are called medium tasters.

For research purposes, sensitivity to PROP is the gold standard, but as we’ll see, there are differences other than PROP sensitivity that separate supertasters from nontasters.

As a rough estimate, about a quarter of the population are supertasters, another quarter are nontasters, and half are moderate tasters. But taste sensitivity varies geographically and with ethnicity. For example, only 3% of West Africans are nontasters. In China, the percentage varies between 6 and 23%. In India, the number is 40%. For people of European descent, the estimate is 30%.

Sensitivity to PROP is something we inherit as part of our genetic makeup. Geneticists used to think taste sensitivity was a dominant/recessive trait controlled by a single gene, but it turns out to be more complicated. More on the genetics of supertasting in my next post .

The enhanced tongue of a supertaster

There’s more to being a supertaster than inheriting the ability to taste PROP. The tongues of supertasters are different from those of nontasters.

In a recent post, I wrote about taste buds on the tongue. Taste buds are located on the sides of papillae, those little projections that cover the surface of the tongue. When it comes to supertasters, we’re interested in the papillae at the front of the tongue. They happen to be called fungiform papillae because, when you magnify them, they look like little fungi or mushrooms.

What makes a supertaster’s tongue different is that their fungiform papillae are smaller and more densely packed, as you can see in the illustration. More papillae mean more taste buds. Supertasters have as many as 1,100 taste buds per square centimeter, compared to nontasters, who can have as few as 11. That by itself makes supertasters more sensitive to taste.

There’s another thing that makes the tongue of a supertaster different: Sensitivity to physical stimulation. Taste buds send information to the brain through two types of nerves. One type sends the taste signals – sweet, sour, etc. The other sends information about pain, temperature, and touch. Since supertasters have more taste buds, they not only detect more bitterness, they’re also more sensitive to peppers and spices in general, heat, cold, and anything painful. They usually dislike the sensation of carbonated water. It’s much too stimulating for their sensitive tongues.

At this point you may be wondering if you’re a supertaster and if being a supertaster makes a difference in what you eat, your health, or your ability to be a wine connoisseur. In the following posts, I describe three different ways to determine your tasting status, as well as the implications for food preferences, wine tasting, and health.

Related posts:
A matter of taste
How do you taste?
Orange juice and toothpaste
The genetics of supertasting
Are you a supertaster: Do you really want to know?
Are you a supertaster: Look at your tongue
Are you a supertaster: How does PROP Taste to you?
Are you a supertaster: DNA testing
Why do we love high-fat foods?
Do we taste fat?
The taste advantage
“Killer” grapefruit?
Grapefruit and the Pill
This is your brain on sugar — and sugar substitutes
The Pepsi challenge: How beliefs affect what you taste