Key concepts

Human biology

Taste

Taste buds

Introduction

Have you ever noticed that some people are a lot pickier about the food they eat than other people are? They might be more selective because they are supertasters! To supertasters, the flavors of foods are much stronger than to average tasters. Whether or not someone is a supertaster comes down to the taste buds on his or her tongue, and you can actually investigate a person's supertaster status by looking at this. Are you a supertaster? Find out with this tongue-based activity!



Background

Do you hate the taste of broccoli? Or think that grapefruit is extremely bitter? If so, you may be able to blame it on your taste buds! Taste buds, located on small bumps on the tongue called fungiform papillae, are each made up of about 50 to 150 taste receptor cells. On the surface of these cells are receptors that bind to small molecules related to flavor. Each receptor is best at sensing a single flavor: sweet, salty, bitter, sour, or umami. The sum total of these sensations is the "taste" of the food.

The number of taste buds varies from person to person. People who have relatively more taste buds are called supertasters. To supertasters, foods may have much stronger flavors, which often leads to supertasters having very strong likes and dislikes for different foods. Supertasters often report that foods like broccoli, cabbage, spinach, grapefruit and coffee taste very bitter. The opposite of supertasters are non-tasters. Non-tasters have very few taste buds and, to them, most food may seem bland and unexciting. The people in the middle are average tasters. Which kind of taster do you think you are? What about your friends and family?

Materials

• Paper-hole reinforcers (one for each volunteer)—or clean wax paper, a standard hole puncher and scissors (instructions below)

• Water and soap

• At least five volunteers (such as friends and family)

• Blue food coloring

• One glass of water for each volunteer

• Magnifying glass

• A bright light or flashlight

• Scrap of paper and a pen or pencil

Preparation

• If you do not have paper-hole reinforcers, wash your hands with soap, take a clean piece of wax paper, and punch one hole in it for each volunteer. Cut out each hole so that you have at least five, small wax paper "rings."

Procedure

• Wash your hands thoroughly with soap.

• Have the first volunteer open his or her mouth. Place a drop of blue food coloring on the tip of his or her tongue. Do not let the tip of the food coloring tube touch the volunteer's tongue.

• Have the volunteer take a mouthful of water, swish it around in his or her mouth, and then spit it out.

• Ask the volunteer to make his or her tongue relatively dry by swallowing a couple of times. The remaining dye should stain all of the tongue blue except for the fungiform papillae, which will look like relatively large, lighter blue or pink bumps (in a sea of dark blue). These papillae are where the taste buds are.

• Put a wax paper ring (that you prepared) or a paper-hole reinforcer on the tip of the volunteer's tongue, in the area that has been dyed.

• Using a magnifying glass under bright light, count the number of papillae within the hole. How many papillae are within the hole? Write this number down along with the volunteer's name. Tip: Don't count the really tiny bumps – just count the larger ones.

• Your volunteer can now remove the paper ring or paper-hole reinforcer from his or her tongue.

• Repeat the entire procedure with at least four more volunteers. Before testing each volunteer, wash your hands thoroughly with soap, and use a new cup with fresh water for each person. If you want to try this on yourself, have someone else count your papillae, or count them in a mirror.

• How many papillae did most people have? Did people have different amounts of papillae, with some having a lot more than others? Knowing that if a person has more than 30 papillae they are considered a supertaster, were there any supertasters in your volunteer group? If so, how many?

• Extra: Repeat this activity with at least 25 more volunteers, for a total of at least 30 people. What percentage of people in this larger group turns out to be supertasters? What percentage are non-tasters, having fewer than 15 papillae? What percentage has between 15 and 30 papillae, and are average tasters?

• Extra: Try this activity again but this time use an equal number of male and female volunteers, with at least 15 of each. Do males and females have the same likelihood of being a supertaster?

• Extra: Look into how different foods, like spinach and chili peppers, taste to the different types of tasters. Based on this, can you make a taste-test to figure out who is a supertaster? Check how accurate your taste-test is by also counting the papillae for each person.

• Extra: You can use a person's body mass index (BMI, formulas for which can be found online) and their results from this activity to try to figure out if there is a correlation between people's weight and the type of taster they are (supertaster, non-taster, or average taster). Do you find a correlation? Are supertasters more likely to be underweight, average, or above weight?





Observations and results

Did you find that people had different amounts of papillae, and that most people were not supertasters?

Typically when people do this activity if they have more than about 30 fungiform papillae they are considered a supertaster, if they have around 15 to 30 papillae they are an average taster, and if they have fewer than 15 papillae they are a non-taster. Although the percentages vary around the world and with different populations of people, around 25 to 30 percent of people are thought to be supertasters, 40 to 50 percent average tasters, and 25 to 30 percent non-tasters. (If you tested only five people, you may not have seen that around 1-2 people, or about 25 to 30 percent, were supertasters because of the small sample size. Additionally, if you only used genetically related family members this may have skewed the results as well since there is a genetic component to how many taste buds a person has.) Testing a person's sensitivity to a bitter chemical called 6-n-propylthiouracil (PROP) is a more definitive way to determine if he or she is a supertaster; non-tasters can't taste PROP, but supertasters can and really don't like its bitter taste! Average tasters can taste it too, but its bitter taste is not strong enough to bother them.

More to explore

Science of Supertasters from BBC Science

Sensing Fat from Beverly J. Tepper and Kathleen L. Keller at The Scientist

What are Taste Buds? from KidsHealth

Do You Love the Taste of Food? Find Out if You're a Supertaster! from Science Buddies