Taste: Surprising Stories and Science About Why Food Tastes Good (6 page)

The Distribution of Taster Types

The area under the curve contains the entire human population. Tolerant Tasters make up about 25 percent of the population. Tasters make up the majority, and HyperTasters make up about 25 percent.

I call the groupings of tasters
HyperTasters
(in lieu of Supertasters),
Tasters
, and
Tolerant Tasters
(in lieu of Nontasters). HyperTasters are on the far right end of Bartoshuk’s bell curve because they have the highest number of taste buds. They are like really ticklish kids. You can excite their buds without much stimulation, the same way you can make a supersensitive kid start giggling hysterically before you even touch her, much less tickle her. These people are very sensitive to the tastes on their tongue. A small amount of something will tickle their taste buds powerfully. They usually have very strong likes and dislikes because they taste so much intensity, things can often be overwhelming, in both good and bad ways. They are often focused, maniacally, on food. Others, ostensibly those at the sensitive end of the Hyper-Taster grouping, may eat a bland diet, having been burned too many times by the strong bitter or sour tastes they’ve experienced. Roger says this is why he eats mostly “safe” foods.

The opposite of HyperTasters are Tolerant Tasters, who are at the other end of the spectrum. These Tolerant Tasters may barely notice the taste of a food at all. They’re usually tolerant of a broad range of flavors and foods. Tolerant Tasters are at the far left end of the distribution curve with the smallest number of taste buds. They don’t sense a lot of strong tastes, so they don’t usually have a lot of strong dislikes. They may drink their coffee black because they don’t taste black coffee as bitter. They may choose intense, bitter red wines because to them, these wines don’t taste so intensely bitter. They’re much less likely to be obsessed with food than people like me. Tolerant Tasters are the most fun to cook for—they complain the least.

Linda Bartoshuk herself falls into my Tolerant Taster grouping. She describes herself as “an extremely insensitive nontaster,” as I probably would have guessed after eating two meals with her, had she not told me. She’s picky, but this is driven almost entirely by her food allergies. She needs to avoid all dairy products, eggs, and gluten, which, she says, “Really kills breakfast.” Then she reminds herself, thankfully, “I can eat hash browns and bacon!”

If anyone ever tries to tell you that you don’t have a palate that’s discriminating enough to know much about taste, you can always tell them that one of the (if not
the
) world’s leading taste experts is a Tolerant Taster. You don’t have to be a HyperTaster to be an expert on taste.

Tasters make up the largest percentage of all tasters. They fall in the center
of Bartoshuk’s distribution. Keep in mind that, although the majority of the population (40 to 50 percent) falls into this category, Tasters can run the gamut. People who are Tasters can have almost no taste buds on their tongue, meaning that they don’t experience much intensity (these Tasters border on being Tolerant Tasters). But other Tasters can have almost as many taste buds as Hyper-Tasters, so they, too, can be excessively sensitive. It just depends where Tasters fall within their grouping: in other words, where they fall within the largest, middle group of tasters.

I have often met a married couple or a pair of siblings, one of whom would eat just about anything while the other one had a laundry list of things he or she wouldn’t eat. We might assume that the ones with the limited diets are not very “good” at tasting or that they are less open-minded than people with a larger repertoire of food. Both of these assumptions are far from universally true and may in some cases be false. Often, people who have very limited diets are HyperTasters. While this may seen counterintuitive, it makes perfect sense. To illustrate, let me use a different sensory discrepancy between Roger and me.

My hearing is much better than Roger’s. While he attributes this to having attended too many Dire Straits and Tom Petty concerts in his youth, I know that his father suffers from the same subtle loss, so it’s most likely genetic. Sometimes I’ll walk in on Roger watching television and the sound is turned up so loud that I worry the neighbors are going to complain. He and I (and many men and women) experience the same level of decibels differently. I have to remind myself of this when I’m cooking for Roger. To him, the bitter vegetal notes of butternut squash are excruciatingly loud. To me, they give this sweet, starchy vegetable a pleasant complexity. We’ve learned to compromise. He turns the sound down while watching the tube and I no longer make him eat green vegetables that aren’t drowned in hollandaise to temper the bitterness he experiences from them.

When the idea of segmenting people into groups based on their taster type was still new, Bartoshuk discovered that she could distinguish between the HyperTaster type and others by measuring people’s ability to taste a single bitter chemical called PROP (6-n-propylthiouracil), pronounced “prope.” To Hyper-Tasters, this chemical tastes horribly bitter. To Tolerants, it has no flavor at all. What a fantastic discovery this was at the time! This meant it was possible to simply ask people to taste a glass of water with a few drops of PROP in it and, if they reacted violently, you could anoint them HyperTasters. If they had a moderate reaction to it, you would call them Tasters, and if they tasted nothing, you’d call them Tolerant Tasters. This was a relief because it was so much easier than asking people to taste samples of hundreds of different foods and standardizing their responses, as researchers had to do to determine taster types in the past.

As is often the case in science, later work demonstrated that it wasn’t quite so simple: There are HyperTasters who cannot taste PROP, and some Tasters who can. Sometimes the single-chemical PROP test gave an inaccurate result. It turns out that individual differences in taste sensation are much more complicated than initially thought. There are three main factors that account for individual differences in ability to taste. The first factor is the anatomy of your tongue, which is measured by counting your taste buds. The second factor is your medical history, and the third factor is your genes.

In addition to the density of taste buds on your tongue, the second indicator of taster type is your medical history. There are many things that can happen to you that can affect your ability to taste.

For example, an ear infection can damage the chorda tympani taste nerve, which runs from the tongue up through the middle ear to the brain. Viruses, including flus and herpes, can also damage this nerve, resulting in the death of innocent taste buds and taste bud bald spots. This is a great reason to get a flu shot every year and to treat earaches immediately (not to mention that treatment relieves the often-excruciating pain). If you had serious ear infections as a child, it’s likely that creamy, fatty, and fried foods send you over the moon because, if your chorda tympani taste nerve was damaged, your trigeminal nerve (the one
that carries texture information) may be now be singing loudly without inhibition. I am somewhat certain that Roger’s childhood ear problems gifted him with a love of foie gras, burgers, cheese, and ice cream.

Accidents, especially head injuries, can also result in loss of some taste (and smell) function. For this reason, if you value your sense of taste, always buckle your seat belt; wear a helmet when you bike, ski, or skate; and forgo head-banging sports like American football and boxing.

Wisdom tooth extraction, a common surgery, occurs precariously close to the chorda tympani taste nerve. If wisdom tooth extraction surgery goes wrong, it can damage taste irreparably, even though that may not be the dentist’s fault.

Another perpetrator of crime against taste buds is disease. Parkinson’s disease, for example, may result in the loss of the sense of smell. And decreased ability to smell is one of the harbingers of Alzheimer’s disease. If you have any of these conditions, you may not be able to taste certain things even if you have a heavy concentration of taste buds on your tongue. In other words, being an anatomical HyperTaster doesn’t mean you can taste more than Tasters or Tolerant Tasters. It’s not so black and white.

Surgery and dental work might explain the bald spots on my tongue. When I was a child, I had a benign cyst on the underside of my tongue. It was removed during outpatient surgery and I rarely think much about it, except when it’s about to rain. One of the strange results of this surgery is that I can detect changes in barometric pressure with my tongue. When the clouds are about to burst, my tongue starts to throb—my own, internal barometric pressure gauge.

One of the other results of my surgery, Bartoshuk and her colleagues think, was damage to the taste buds on my tongue. The location and existence of my bald spots seem to indicate damage to my trigeminal nerve, the nerve that carries pain information from my mouth to my brain. The phenomenon I mentioned earlier, the release of inhibition, means that when this nerve was injured, its ties to the taste buds in a certain area of my tongue were clipped. These abandoned buds eventually withered and faded away, leaving behind bald spots. This allowed other areas on my tongue the freedom to scream a little bit louder, without inhibition.

Roger’s tongue showed some damage too, probably due to oral surgery he had to remove his uvula to widen his airway. His uvula surgery did two things that directly benefit me. First, it relieved his most bed-shaking snoring. Second, it resulted in the loss of some of his taste buds, thereby giving him a bit of humility when it comes to our taste rivalry.

It turns out that Roger and I are both HyperTasters, as proclaimed by Bartoshuk’s graduate student Jennifer Stamps after eight hours of thorough evaluation of our tongues. Was she sure about me, I asked, given my bald spots?

She responded, “Your intensity rating to the PROP test paper was definitely a HyperTaster rating: a 90. I know you have trigeminal damage because when the nerve endings degenerate, they take out the taste buds they once surrounded and leave behind holes and bare spots. Your ratings for taste on the tip of your tongue may be lower than before your loss of taste buds but they were decent for the ones you have left, which indicates your chorda tympani taste nerve is working fine.”

Whew. This was a great, huge, relief.
Thankfully
, I thought to myself,
I have absolutely nothing to hide with regard to my professional fitness.
Roger and I flew back to California together, radiating relief from having been anointed HyperTasters.

It wasn’t until about a week later, after a glass of wine or four, that Roger again brought up the trip to Florida. Perhaps I deserved it, having doubted his tasting ability in some capacity. Or perhaps it was just his competitive side flaring up again. Regardless, he mischievously hinted at a truth he was concealing for my own benefit.