Accounting for taste
Instead of speed slamming a burger down your gullet, the next time you stuff your face, why not take a moment to appreciate your buds — you know, your taste buds. I’m one of 10,000 taste buds on and around your tongue, working hard to help make your life more flavourful.
Gustation, the fancy word for taste, is a multimedia experience. Smell, for example, is crucial; you can lose up to 80% of your gustatory ability with a bad cold. The look of foods affects your expectations. Once inside your mouth, sensors of various sorts respond to its texture, temperature and my favourite, chemistry. We’re too small to see with your naked eye, but you can admire our housing projects, known as papillae. Stick out your tongue in a mirror, or look at someone else’s if you’re the romantic type. Touchy-feely papillae carpet most of your tongue. As a sensitive lot, we taste buds avoid the hurly-burly of coarse foods and gnashing teeth. We prefer the three other types of papillae: little round blips shaped liked mushrooms, near the tip of your tongue; a cookbook of pages along the edges of your tongue, toward the back; and near these on the upper surface, circular booths with round tables.
Cool experiments
For some, changing tongue temperature stimulates tastes. Most common is sweet and least common, salt. Subjects more often tasted sweetness at the front, sourness along the sides and bitterness at the back. Try it with ice cubes.
Not for all tastes
Scientists have discovered chemicals that some people can taste and others can’t. Among tasters, some are especially sensitive; they are Supertasters. The significance of this remains unclear. Supertasters tend to eat less fatty foods, which is good, but they also eat less green vegetables, which is not so good.
You may have seen taste maps designating particular parts of your tongue to specific tastes. Yet if you study your own experiences, though you might notice degrees of sensitivity, you should be able sense all tastes wherever you have taste buds. That map will just get you lost. Still useful is the idea of basic tastes — saltiness, sweetness, sourness, bitterness and umami. Western scientists only recently recognized umami, a Japanese word, meaning savory or meaty. These basics probably helped way back when you guys weren’t so bright. Sweet, salty and umami tastes indicated carbohydrates, salt and protein, back when these were in short supply. Sour and bitter tastes hinted at poisons, so it was good we could detect them at lower concentrations. These days, eating sensibly must be tricky with all your hyper-abundant, newfangled fatty foods. Maybe you’re still not so bright.
Spice of life
Spiciness is a different kettle of fish. The nerves for temperature and pain respond to hot spices as a physical irritant. The same is true for the coolness of mint or the burn of alcohol.
Now check out my bud. Go ahead, I’m not shy. Food chemicals arrive by saliva at my pore. To greet them, little fingers reach out from each of my 40-odd receptor cells. They send news about who they’ve met to nerve endings. With something small like a salt ion, the signal goes direct. More complicated molecules, like those related to sweet or bitter tastes, require discussion with other receptor cells to get consensus before sending a signal. The lower part of your brain receives all these signals like notes in the score of a symphony. Other parts of your brain respond to the performance with cheers or rotten tomatoes. Speaking of tomatoes, I’ve got work to do, processing more of your spit.
This article was first published in September 2003 as part of the “Science in the City” series in The Vancouver Courier.