Imagine biting into a naturally ripened pear direct from the tree. As you bite into it, it fills your mouth and teases your taste buds with that delicious, juicy sweetness. As you might guess, taste is one of our primary senses. It is simply your ability to perceive flavors in food and liquids. “Your taste buds are sensory organs that enable you to perceive different flavors in food.” (1)
Your taste receptors are on the tongue and different parts of the tongue are responsible for different types of tastes. Over 10,000 taste receptors or taste buds transmit messages to the brain which allows you to perceive taste. Each taste experience is caused by a specific type of receptor on the taste bud. There are now considered five basic taste sensations: sweet, sour, bitter, salty, and umami. The last taste sensation, umami, is a relatively new designation. Umami is experienced as a savory taste from eating protein foods containing glutamate.
Have you ever noticed that some people can enjoy all types of taste sensations and that some are really sensitive to taste and are picky about which foods they enjoy and don’t enjoy? One in four people are “super-tasters.” These folks are more sensitive to the different tastes, especially to bitter tasting foods. As you may know, your sense of smell is directly related to your sense of taste. When you have a cold, your taste buds are blunted. Also, many medications can alter your taste perceptions. Zinc is needed for healthy taste receptor function and a deficiency in zinc can certainly alter taste receptivity.
When food cravings are discussed, sweet tasting foods are always central to that discussion. Sweetness is always considered a very pleasurable taste sensation. It allows you to determine the caloric density of foods, as sweet tasting foods are normally calorically dense foods and cause significant rises in blood sugar, which can lead to quicker energy. But, did you know that your drive to eat ever larger quantities of sugar and sugar-laden foods may be driven by your weight? You may think that eating too much sugar can cause weight gain, but weight gain can actually drive you to eat larger and larger quantities of sugar.
According to a 2008 study, obesity can gradually numb the taste sensation to sweet foods and drive the consumption of larger quantities of sweet tasting foods to feel satisfied. At lower levels of sugar, compared to lean mice, the brains of the obese mice responded with less activity when their tongues were exposed to sucrose. When they were fed a higher concentration of sucrose, their nerve cells “fired more vigorously.” The researchers believe that over time the exposure to sweet foods can influence the reward centers of the brain and thus impact taste perception. The enhanced taste of the sweetness “stimulates taste and food reward neurons on a chronic basis, making them less sensitive over time.” (2) This can become a chronic cycle of eating sugar, gaining weight, and in gaining weight, augmenting addiction to ever and ever higher levels of sugar intake.
When you bite into cranberry sauce and the tartness hits your tongue or when you experience the taste of a lemon, you are overwhelmed by the taste of sour. Of the five taste sensations, sour is the strongest and is evoked by acidic substances. The more acidic the substance, the more sour the taste. Research into how our taste buds register different taste sensations has shown that the acid substances release protons and that in this exchange the sour taste receptors detect the taste for sour. (3) The most common food groups that contain naturally sour foods are the citrus fruit family, grapes, and wine. Sour candy, usually containing citric acid, is very popular in the United States.
When tasting carbonated beverages, you can thank your sour taste bud receptors, as well. You are not actually detecting the bubbles on your tongue, but the carbon dioxide which creates the fizz. A study was undertaken through the NIH and Columbia University to find out how our taste receptors respond to carbon dioxide. They “monitored the activity of a nerve that carries signals from taste receptor cells in the tongue in mice that were genetically engineered to lack cells needed to sense specific tastes. They found that mice without sour-sensing cells did not respond to carbonation.” But, those mice which had their sour receptors intact, did react to carbonation. The researchers were able, also, to identify a specific enzyme, carbonic anhydrase 4, that responds to carbon dioxide. (4)
The taste for bitter is your most sensitive taste sensation. Many of us perceive it as unpleasant, in fact, even disagreeable. From an evolutionary standpoint, the bitter taste is common to poisons and common in today’s world with toxins and chemicals. It is also subject to genetic variations, so that some people enjoy bitter foods and others are repulsed by them. Bitter foods are important for healthy digestive function. Many people in the world take herbal bitters before meals to enhance stomach acid secretion. Other bitter foods include leafy green vegetables, licorice, and fennel.
Salty taste receptors respond to sodium ions. Any food or salt that contains high levels of sodium tease these receptors. It is also one of those taste sensations that people crave. Potato and corn chips are among the most popular snacks in the U.S. There is a research that indicates that a desire for salty tastes is related to early childhood dietary experiences. A study undertaken in 2011 and published in the American Journal of Clinical Nutrition found that infants who were tested at 2 and 6 months and who had exposure to starchy table food that contained sodium, were most likely to desire salty foods. In fact, the infants were more likely to lick salt from the surface of foods by pre-school age and were more likely to eat plain salt. (5)
The word in Japanese for “great taste” is umami. This is a newly recognized taste sensation. Chefs have spoken of savory tastes for years, but the general public is just becoming aware that it is a special taste sensation. It is considered fundamental to many Eastern cuisines. Umami represents the taste of the amino acid L-glutamate. (5)
It is often described as a meaty taste and is at its optimum when combined with salt or other umami tastes. Think of a meal of pasta with a tomato sauce with mushrooms combined with Parmesan cheese. The taste is stronger and heartier with the combination than with tomato sauce alone. The umami taste is found in fish, shellfish, cured meats, meats, mushrooms, tomatoes, spinach, celery, green tea, and fermented foods such as miso, soy sauce, and cheese.
Combining Different Taste Sensations
Have you ever craved something sweet after you have tasted something bitter? All of the different taste sensations fulfill us in different ways and we most often choose foods based on these tastes. Think of eating a meal that contains all of the taste sensations:
Salad(bitter) with lemon juice drizzled over the lettuce (sour) accompanied by an apple (sweet), and some raw, salted walnuts (salty). Now, add a savory piece of chicken and you have a Chicken Waldorf Salad. Hmmm! I wonder if this would be satisfying?
The flavors found in foods allow us to savor and enjoy food!
- Rinzler, C.A. Nutrition for Dummies, 4th ed.2006: Wiley Publishing, Inc., Hoboken, N.J., p.197
- Route to Obesity Passes Through the Tongue, Nov.26, 2008 at http://www.sciencedaily.com/releases/2008/11/081126133409.htm
- e! Science News, Sour research, sweet results, Nov. 24, 2010, at http://esciencenews.com/articles/2010/11/24/sour.research.sweet.results
- Study: When Soda Fizzes, Your Tongue Tastes It, Oct. 15, 2009 at
- Leslie, J. et.al. The development of salty taste acceptance is related to dietary experience in human infants: a prospective study, American Journal of Clinical Nutrition, January, 2012, vol.95: no.1, 1123-129.