How we taste and why we like or don’t like what we taste are fascinating and somewhat mysterious questions. Our food preferences, it seems, are determined by multiple factors, including genes, experience and age. The following should answer most of your questions about this important aspect of our eating experiences.

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What is taste? 
Technically, “taste” refers to the sensory experiences produced by stimulation of taste receptors on the tongue and palate. “Taste sensations not only provide information about the nature of the food but also produce affect (an emotion or feeling); that is, taste sensations are pleasant or unpleasant,” says Linda Bartoshuk, Ph.D., professor of otolaryngology at Yale University School of Medicine. “This (mechanism) is hard-wired in the brain. Babies are born loving sweet and hating bitter.” This is a preference handed down from our evolutionary past, according to Steven A. Witherly, Ph.D., president and CEO of Technical Products Inc., a food consulting firm in Valencia, Calif. “The environment was very low in salt, fat and sugar, and our sensory systems, therefore, evolved to find these rare ingredients very pleasurable and inviting."

And Witerly adds that there is also a psychological component to taste -- all sensations created by food in the mouth can activate memory centers throughout the brain that may modify our perception. So memories you associate with a food might also affect how it appeals to you.

Experience is another important determinant of food preferences. “For example, infants and young children need to learn which foods are safe to eat. Even before birth, information about specific flavors of mothers’ diets passes to infants through amniotic fluid. This very early learning continues after birth through flavors in breast milk,” says Marcia L. Pelchat, Ph.D., of the Monell Chemical Senses Center in Philadelphia.   

Can you adjust your taste and make it more sensitive?
To a certain extent, you can. For example, if you stop eating salty or sugary foods, your taste adjusts so that when you do eat something even mildly salty or sweet, your reaction to it will be exaggerated. And that is specifically a result of your perception of the taste of the food, not its chemical properties. So, if you ate virtually no foods that tasted salty (such as pretzels or salty peanuts) for a month, but continued to eat foods with hidden, tasteless salt (such as bread or even tasteless salt pills), you would still become salt-sensitive, explains Pelchat. “It’s your brain that’s adjusting, not the taste.”

How long does it take your “taste” to adjust? Witherly says sodium appetite can change pretty quickly, within weeks. “Sugar and fat are more difficult, and some scientists believe that the brain never forgets the taste of sugar or fat -- especially the combination of the two.

“The problem is, the brain has a memory for higher-salt pleasure, and it is easy to go right back to preferring higher levels of salt. The same is true of sweet taste -- which is a hard-wired food pleasure. We do not learn to like salt or sugar -- the brain is pre-wired to prefer such things,” says Witherly. “It might take you a month or more to get used to low salt, but it will take less than a week to go back.” 

Is it true that as much as 80 percent of what we perceive as taste is actually smell?
Not true. The confusion comes in because we use the word “taste” to refer both to real taste (sweet, sour, bitter, salty, then we add “umami” or MSG taste) and to the sensations evoked when we put food in the mouth, says Bartoshuk. In fact, taste and smell are separate senses that combine in a unique way in the brain. We have special areas in the cortex just for the combination of taste, smell and texture. “The major function of taste is to evaluate whether what is in the mouth is friend or foe, whereas the major function of smell is to identify or memorize what the food is for future reference -- was it good, and did it have calories. The taste of food is the major pleasure stimulator, whereas our sense of smell allows us to recognize what is good or bad based on prior experience. So smell acts like a gatekeeper for final ingestion, and the taste of food generates the major pleasure of ingestion,” says Witherly.

However, according to Pelchat, the distinctive flavors of most foods and drinks come more from smell than taste. “Sugar has a taste (sweet), but strawberry actually is a smell. An airway between the nose and mouth lets people combine aroma with the five basic tastes to enjoy thousands of flavors.” She recommends the “jelly bean test” to demonstrate: Take two red jelly beans of differing flavors, e.g., cherry and strawberry (but not cinnamon), and, while holding your nose tightly closed, pop one into your mouth and chew. Try to identify the flavor. You’ll know that it’s sweet, but you won’t be able to determine whether it’s cherry or strawberry until you let go of your nose and allow the olfactory information to whoosh up. “The perception of flavor also includes information from temperature, texture, irritation (e.g., chili peppers or ginger) and other modalities,” adds Pelchat

How many odors can we sense?
“We have about 50 million olfactory [smell] receptors, of which about 500 different types are finely tuned to just a few odorants,” says Witherly.

The number of odors you can recognize depends on your experience with them. You can’t recognize an odor that you have not smelled previously. And if you’re talking about actually naming them, the number is significantly smaller (probably fewer than 100).  The olfactory system operates by analyzing chemical structure. When a molecule (or group of molecules) hits your olfactory receptors, it creates a pattern in the brain that describes the important parts of those molecules. Basically, that pattern tells you the molecular structure of the stimulus. These patterns are somehow stored in the brain and become associated with a particular reaction, depending on whether the object you smelled does something good for you (e.g., calories) or bad (e.g., poisons you and makes you nauseated). Thus the smell of bacon, for example, produces a pattern that is stored in memory. When that pattern is excited, you smell bacon, explains Bartoshuk

How many tastes are there?
According to Witherly, the basic tastes are sweet, sour, bitter and salty, to which we add “umami” or MSG taste, “hot pepper” or vanilloid taste, “fatty acid” taste and “water” taste. We also sense texture, temperature and pain. 

Does taste change as we age?
Studies show that the sense of taste doesn’t really diminish much with age, but the sense of smell can dramatically decline past the age of 60, says Witherly.   

True or false: We have thousands of taste buds? 
True -- we have many taste buds in the mouth, and in each one there can be as many as 50 individual taste cells. However, according to Bartoshuk, the number of taste buds varies from one individual to the next. Some people (“nontasters”) have relatively few taste buds; others (“supertasters”) have many more. Most people are medium tasters and have an intermediate number of taste buds. And by the way, “If you don’t like really hot and spicy food and you find coffee too bitter, you’re probably a supertaster,” says Witherly. 

What are taste aversions, and how do they develop?
Taste aversions appear to result from pairing nausea with a taste. In humans, these are not actually taste aversions at all. They are aversions to the odors of the food leading to nausea perceived through your nose. They are more accurately called “food aversions,” says Bartoshuk. And according to Witherly, all it takes is one pairing of a food with gastrointestinal illness or sickness to form a permanent food aversion. This phenomenon is meant to protect us from harm. Remember that 90 percent of all foods in the environment may be poisonous. 

What makes vanilla the most popular flavor?
Most experts believe that liking or disliking odors is a learned experience. And since vanilla is familiar, often associated with a nurturing context (e.g., Mom, breast milk, infant formula) and with pleasurable sweet and fatty foods, we have positive memories each time we smell vanilla, says Witherly. 

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CHARLES STUART PLATKIN is a nutrition and public health advocate, founder and editor of DietDetective.com, the health and fitness network. Copyright 2008 by Charles Stuart Platkin. All rights reserved. Sign up for the free Diet Detective newsletter and iTunes podcast at www.DietDetective.com.

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written by Taylor, September 06, 2007

Cool i guess.