A young man and woman are enjoying their first date. He wants to impress her with his taste in food, so he takes her to his favorite deli and buys a pastrami on rye for them to share. He unwraps the sandwich, gives her half, and bites into his portion.
He closes his eyes and savors the blend of meat, Swiss cheese, and mustard. Then he looks at his date, expecting to see her caught up in equally rapturous enjoyment, but instead, her face is pinched up in the middle, and she’s holding the food at arm’s length, as though she’d found something with six legs wedged between the bread and the pastrami.
“I don’t like caraway seeds,” she says.
The young man curses his impudence and buys his date her choice of sandwich: turkey on whole wheat with mayonnaise, lettuce and tomato. Now it’s his turn to gag. “Whole wheat?”
Is this relationship doomed because of taste incompatibility? Or can these two still find common ground, marry and have children that will turn up their noses at everything but dry Cheerios? The answers to these questions exceed the scope of this article, but with respect to food, the mystery of why certain tastes appeal to some people and not others is one of the great mysteries of human physiology. Scientists have some reasonable theories, though.
Leslie Stein, Ph.D., media contact at Monell Chemical Senses Center, a scientific institute for research on taste and smell in Philadelphia, Pa., says recent research suggests a person’s genes helps to determine how he or she detects basic tastes by affecting the configuration of his or her taste receptors.
“Part of why you might like broccoli while your best friend finds it bitter is because you have different genes,” she says.
Experience is also an important determinant of food preferences, Stein says. For example, infants and young children need to learn which foods are safe to eat. Even before birth, information about specific foods in the mother’s diet pass through her amniotic liquid. This early learning continues following birth through the taste of the mother’s breast milk.
“We also know repeated exposure can increase liking for a certain taste in children and adults. For example, Monell research has shown that people who stick to a low sodium diet for a period of time come to prefer lower levels of sodium in their food,” Stein says.
Humans can’t change their genes, though, so some food likes or dislikes might be difficult to alter drastically, Stein says.
“Repeated exposure to some food likes or dislikes can increase relative liking for a food, but might not be able to change a disliked food into one that’s liked. Exposure might, however, make a disliked food less disliked.”
Scientists believe humans detect five basic taste qualities: sweet, sour, bitter, salty, and savory. Almost all humans like sweet taste, probably because the brain associates it with energy for the body, Stein says. Salty taste is thought to signal sodium, which is necessary for survival. Taste can also signal danger, as many poisons taste bitter.
The science of taste goes even deeper. According to a “taste primer” published by Monell, specific chemicals stimulate each taste; receptors on cells located in taste buds within the mouth then recognize these stimuli.
Humans have around 10,000 taste buds, although not all taste buds are located on the tongue, the “taste primer” reports. Some are found on the roof of the mouth and in the throat. Each taste bud contains about 50 to 80 specialized cells. At the top of each taste bud is a small opening where a few cells are exposed to the inside of the surface of the mouth. These exposed cells contain the receptors that detect taste stimuli. Activated cells communicate with other cells within the taste bud, some of which relay messages about the presence of taste stimuli to nerves connected to the brain.
The union triggers a series of biochemical reactions inside the receptor cell. Known as transduction, these reactions translate chemical information from the taste stimulus into an electrical message the brain can understand. Different kinds of receptors and transduction sequences help distinguish between sweet, sour, salty, bitter, or savory.
A person’s sense of taste acts as a gatekeeper when he or she ingests food. By analyzing food quality, taste helps the person decide whether to swallow something that’s in his or her mouth. While science has made great strides toward understanding why people like some foods and dislike others, it’s still working on accounting for a person’s taste in men or women. Until that’s worked out, common sense suggests waiting on the pastrami on rye until the second date.