The simplest joy in a person’s life is delicious food. It would seem that you go to the kitchen, open the refrigerator, spend a certain amount of time at the stove - and voila! – a fragrant dish is already on the table, and endorphins are in your head. However, from the point of view of science, the entire meal from start to finish is a complex multifaceted process. And how difficult it is sometimes for us to explain our eating habits!

The study of taste buds is carried out by a young and still developing science - the physiology of taste. Let's look at some basic tenets of the teaching that will help us better understand our taste preferences and momentary weaknesses.

Human taste buds

Taste is one of the five senses of perception, which are very important for human life. The main role of taste is to select and evaluate food and drink. Other senses, especially smell, help him a lot in this.

The taste mechanism is driven by chemicals found in food and drinks. Chemical particles, collecting in the mouth, turn into nerve impulses that are transmitted along the nerves to the brain, where they are deciphered. The surface of the human tongue is covered with taste buds, of which an adult has from 5 to 10 thousand. With age, their number decreases, which can cause certain problems with distinguishing tastes. The papillae, in turn, contain taste buds, which have a specific set of receptors, thanks to which we experience the whole gamut of taste diversity.

They respond to only 4 basic tastes - sweet, bitter, salty and sour. However, today a fifth element is often identified – umami. The newcomer’s homeland is Japan, and translated from the local language it means “appetizing taste.” In fact, umami is the taste of protein substances. Monosodium glutamate and other amino acids create the umami sensation. Umami is an important component of the taste of Roquefort and Parmesan cheeses, soy sauce, as well as other non-fermented foods - walnuts, tomatoes, broccoli, mushrooms, and cooked meats.

Thus, recently scientists have tended to think that some people perceive the same taste differently and that some are programmed to gain weight from French fries, while others can eat them without harm to their figure - this is a matter of heredity. In support of this statement, scientists from Duke University in the USA, together with colleagues from Norway, proved that people have a different composition of genes responsible for odors. The study focused on the relationship of the OR7D4 RT gene to a steroid called androstenone, which is found in high quantities in pork. Thus, people with identical copies of this gene are disgusted by the smell of this steroid, and owners of two different copies of the genes (OR7D4 RT and OR7D4 WM), on the contrary, do not feel any hostility.

Interesting facts about tastes

• Taste buds on the human tongue live on average 7-10 days, then they die and new ones appear. So don't be surprised if the same taste tastes a little different from time to time.

• About 15-25% of people in the world can safely be called “supertasters,” that is, they have an extremely sensitive taste, since there are more papillae on the tongue, and therefore more taste buds.

• The taste buds on the human tongue for sweet and bitter tastes were discovered just 10 years ago.

• All pure tastes are felt absolutely equally by a person. This means that we cannot talk about several types of sweet taste. To taste, there is just one sweet taste, which, however, can vary in intensity: be brighter, richer or faded. The situation is similar with other tastes.

• Taste buds are most sensitive between 20-38 degrees. If you cool your tongue, for example, with ice, you may no longer feel the taste of sweet food, or it may change significantly.

• Good taste is formed in the womb. Thus, scientists have found that the taste of some foods is transmitted not only through mother’s milk, but also through the amniotic fluid while the baby is in the mother’s belly.

• American scientists conducted a study that established the dependence of taste preferences on a person’s age and gender. So, girls mostly prefer sweets, fruits, and vegetables. Boys, on the contrary, love fish, meat, poultry and, for the most part, are indifferent to chocolate.

• During air travel, due to the high noise level, a person's taste sensitivity to salty and sweet things decreases.

• The taste of the cookies is 11 times better when washed down with milk drinks. But coffee, on the contrary, “kills” all other sensations. Therefore, if you want to fully enjoy your dessert, it is better to choose the right drinks and drink coffee separately from other food.

Sweet

Sweet taste is perhaps the most pleasant for the majority of the world's population. It is not for nothing that the expression “sweet life” appeared, and not any other. At the same time, not only flour and confectionery products are sweet, but also products of natural origin. Along with this, they are also useful. Most sweet foods contain large amounts of glucose. And as you know, glucose is the main metabolic fuel for the human body. That is why taste buds easily recognize sweet tastes, and at the same time produce happiness hormones - serotonin and endorphin.Please note that such hormones are addictive. This is the explanation for the fact that we prefer to eat depression and stress with something sweet.

It's no secret that excessive consumption of sweets has an adverse effect on your figure and skin condition. However, you shouldn’t give up desserts completely. Do not eat treats on an empty stomach and, whenever possible, try to replace them with dried fruits, honey, and nuts.

Sour

Most acidic foods contain ascorbic acid. And if you suddenly crave something sour, know that this may indicate a lack of vitamin C in your body. Such taste changes can even serve as a signal of an oncoming cold. The main thing is not to overdo it: you should not actively supply your body with this useful substance, everything is good in moderation. An excess of acid negatively affects the functioning of the digestive system and the condition of tooth enamel.

If a lot of acid is involved in the metabolism, the body will try to get rid of its excess. This happens in different ways. For example, through the lungs by exhaling carbon dioxide or through the skin by sweating. But when all possibilities are exhausted, acids accumulate in the connective tissue, which impairs the functioning of the digestive system and provokes the accumulation of toxins in the body.

The daily requirement of vitamin C for adult men and women is 70-100 milligrams. It is especially abundant in sour berries (gooseberries, currants, cranberries), citrus fruits and kiwis, and fresh vegetables (especially bell peppers).

In modern medical practice, complete or partial loss of taste is often encountered. All these cases are associated with various malfunctions that occurred in the human body. But most often they are found in otolaryngology. It is during an appointment with this specialist that patients often ask: “What to do if you no longer feel the taste of food?” After reading today's article, you will understand why such a pathology occurs.

Causes of the problem

Oddly enough, but most often this pathology develops as a result of neurosis. This is a peculiar reaction of the human body to stress and nervous overload. In these cases, you can hear from the patient not only the phrase “I don’t feel the taste of food,” but also complaints about disruptions in the gastrointestinal tract, surges in blood pressure, and rapid heartbeat.

An equally common cause of this problem is considered to be infectious diseases of the oral cavity or the presence of a decaying dental nerve. In this case, an inflammatory process begins in the human body, affecting

Also, such a pathology can be a consequence of malfunctions of the thyroid gland. Even minimal deviations can lead to serious changes in many systems of the human body.

Doctors often hear the phrase “I can’t taste food” from those diagnosed with a brain tumor. In this case, this symptom may alternate with a feeling of unpleasant odor. So, a well-prepared dish made from quality ingredients suddenly begins to seem stale.

Which specialist should I contact with a similar problem?

Before you go to the doctor’s office and voice your complaint “I can’t taste the food” (the reasons why such a pathology occurs were discussed above), you need to understand which specific doctor you need to see. In this situation, much depends on what accompanying symptoms accompany this pathology.

If, in addition to loss of taste, the patient complains of decreased appetite, rapid heartbeat and surges in blood pressure, then he should definitely consult a neurologist.

In cases where the pathology is accompanied by dizziness, weakness, vomiting, impaired hearing and coordination of movements, you should first make an appointment with an oncologist.

If a person who utters the phrase “I can’t taste food” complains of nausea, vomiting, heartburn and acute pain in the epigastric region, then it is likely that he needs to examine the gastrointestinal tract.

If familiar foods seem bitter, and every meal is accompanied by painful sensations in the right hypochondrium, then you need to visit a hepatologist. It is possible that loss of sensitivity of taste buds, accompanied by flatulence, defecation disorders, insomnia and irritability, is a consequence of cholecystitis.

Diagnostic methods

A person who seeks medical help and voices the phrase “I can’t taste food” will need to undergo several additional tests. They will allow you to establish the exact cause that provoked the development of the pathology and prescribe adequate treatment.

First of all, the specialist must determine the threshold for sensitivity. To do this, the patient is alternately asked to determine the taste of quinine hypochloride, sugar, table salt and citric acid. The results of the study allow us to create an accurate clinical picture and the extent of the problem. To determine the qualitative threshold of sensations, a few drops of a special solution are applied to individual areas of the oral cavity.

In addition, modern doctors have the opportunity to conduct electrometric studies. The patient is also prescribed a number of laboratory tests. They are needed to exclude endocrine diseases. In most cases, the patient is sent for a computed tomography scan.

Why is this pathology dangerous?

It should be noted that it can cause serious health problems. A person who begins to wonder: “Why can’t I taste food?”, in the absence of proper treatment, may subsequently be diagnosed with diabetes, cardiovascular and other diseases.

Disruption of the receptors can result in a person consuming too much salt or sugar. These attempts to improve the taste of food can lead to serious problems. They often lead to depression, hypertension and diabetes.

What to do if you can't taste food?

First of all, you need to make an appointment with a doctor and undergo all the tests he recommends. This will allow you to determine the root cause of the problem and prescribe the correct treatment.

So, if the problem was caused by neurosis, the patient will be recommended to undergo an individual course consisting of auto-training, water and magnetic therapy. He will also be prescribed sedative herbal remedies, and in more serious cases, tranquilizers or bromides. If the reason lies in a malfunction of the thyroid gland, then endocrinologists usually prescribe medications to replenish iodine deficiency.

To improve your taste sensitivity, you need to quit smoking. Often it is this bad habit that causes such problems. Also, taste sensations may be dulled while taking certain medications, including strong antibiotics. In this case, you need to consult a doctor so that he can recommend other medications that do not have such side effects.

In addition, you should make sure that your body receives a sufficient amount of vitamins and microelements. To do this, you need to introduce more fresh vegetables and fruits into your diet. If you lose taste, you should not overuse spices. Otherwise, you risk getting a burn to the oral mucosa.

Inventing a new dish is more important for happiness
humanity than the discovery of a new planet.
Jean-Anthelme Brillat-Savarin

The simplest joy in our life is to eat delicious food. But how difficult it is to explain from a scientific point of view what happens! However, the physiology of taste is still at the very beginning of its journey. For example, the receptors for sweet and bitter were discovered only ten years ago. But they alone are not enough to explain all the joys of gourmet food.

From tongue to brain

How many tastes does our tongue sense? Everyone knows the taste of sweet, sour, salty, bitter. Now, to these four main ones, which were described in the 19th century by the German physiologist Adolf Fick, a fifth has been officially added - the taste of umami (from the Japanese word “umai” - tasty, pleasant). This taste is typical for protein products: meat, fish and broths based on them. In an attempt to find out the chemical basis of this taste, Japanese chemist and professor at Tokyo Imperial University Kikunae Ikeda analyzed the chemical composition of seaweed. Laminariajaponica, the main ingredient in Japanese soups with a strong umami flavor. In 1908, he published a paper on glutamic acid as a carrier of umami taste. Later, Ikeda patented the technology for producing monosodium glutamate, and the Ajinomoto company began producing it. However, umami was only recognized as the fifth fundamental taste in the 1980s. New tastes that are not yet included in the classification are also being discussed today: for example, metallic taste (zinc, iron), the taste of calcium, licorice, the taste of fat, the taste of pure water. It was previously thought that the "fat taste" was simply a specific texture and smell, but a study on rodents conducted by Japanese scientists in 1997 showed that their taste system also recognizes lipids. (We'll talk more about this later.)

The human tongue is covered with more than 5,000 papillae of various shapes (Fig. 1). Mushroom-shaped ones occupy mainly the two anterior thirds of the tongue and are scattered over the entire surface, groove-shaped (cup-shaped) are located behind, at the root of the tongue - they are large and easy to see, leaf-shaped are closely spaced folds in the lateral part of the tongue. Each of the papillae contains taste buds. There are also a few taste buds in the epiglottis, the posterior wall of the pharynx and on the soft palate, but mostly, of course, they are concentrated on the papillae of the tongue. The kidneys have their own specific set of taste buds. So, at the tip of the tongue there are more receptors for sweetness - it feels it much better, the edges of the tongue feel sour and salty better, and its base is bitter. In total, we have approximately 10,000 taste buds in our mouths, and they give us the sense of taste.

Each taste bud (Fig. 2) contains several dozen taste cells. On their surface there are cilia, on which the molecular machine is localized, providing recognition, amplification and transformation of taste signals. Actually, the taste bud itself does not reach the surface of the mucous membrane of the tongue - only the taste pore enters the oral cavity. Substances dissolved in saliva diffuse through the pore into the fluid-filled space above the taste bud, and there they come into contact with the cilia, the outer parts of the taste cells. On the surface of the cilia there are specific receptors that selectively bind molecules dissolved in saliva, become active and trigger a cascade of biochemical reactions in the taste cell. As a result, the latter releases a neurotransmitter, it stimulates the taste nerve, and electrical impulses carrying information about the intensity of the taste signal go along the nerve fibers to the brain. Receptor cells are renewed approximately every ten days, so if you burn your tongue, the taste will only be lost temporarily.

A molecule of a substance that causes a certain taste sensation can only contact its receptor. If there is no such receptor or it or the biochemical reaction cascades associated with it do not work, then the substance will not cause a taste sensation. Significant progress in understanding the molecular mechanisms of taste has been achieved relatively recently. Thus, we recognize bitter, sweet and umami thanks to receptors discovered in 1999 - 2001. All of them belong to the large family of GPCRs ( G protein-coupled receptors), coupled with G proteins. These G proteins are located inside the cell, are excited when interacting with active receptors and trigger all subsequent reactions. By the way, in addition to taste substances, GPCR-type receptors can recognize hormones, neurotransmitters, odorous substances, pheromones - in a word, they are like antennas that receive a wide variety of signals.

Today it is known that the receptor for sweet substances is a dimer of two receptor proteins T1R2 and T1R3, the T1R1-T1R3 dimer is responsible for the taste of umami (glutamate has other receptors, some of them are located in the stomach, innervated by the vagus nerve and are responsible for the feeling of pleasure from food), but we owe the feeling of bitterness to the existence of about thirty receptors of the T2R group. A bitter taste is a danger signal, since most poisonous substances have this taste.

Apparently, for this reason, there are more “bitter” receptors: the ability to distinguish danger in time can be a matter of life and death. Some molecules, such as saccharin, can activate both the sweet T1R2-T1R3 pair of receptors and the bitter T2R receptors (particularly hTAS2R43 in humans), so saccharin tastes both sweet and bitter on the tongue. This allows us to distinguish it from sucrose, which only activates T1R2-T1R3.

Fundamentally different mechanisms underlie the formation of the sensations of sour and salty. The chemical and physiological definitions of “sour” are essentially the same: it is responsible for the increased concentration of H + ions in the analyzed solution. Table salt is known to be sodium chloride. When a change in the concentration of these ions - carriers of sour and salty tastes - occurs, the corresponding ion channels immediately react, that is, transmembrane proteins that selectively pass ions into the cell. Acid receptors are actually cation-permeable ion channels that are activated by extracellular protons. Salt receptors are sodium channels, the flow of ions through which increases with increasing concentration of sodium salts in the taste pore. However, potassium and lithium ions are also perceived as “salty”, but the corresponding receptors have not yet been definitely found.

Why do you lose taste when you have a runny nose? Air has difficulty passing into the upper part of the nasal passages, where the olfactory cells are located. The sense of smell temporarily disappears, so we have a poor sense of taste, too, since these two sensations are closely related (and the sense of smell is the more important the richer the food in aromas). Odor molecules are released in the mouth when we chew food, travel up the nasal passages and are recognized by olfactory cells. How important the sense of smell is in the perception of taste can be understood by pinching your nose. Coffee, for example, will simply become bitter. By the way, people who complain of loss of taste actually mostly have problems with their sense of smell. A person has approximately 350 types of olfactory receptors, and this is enough to recognize a huge variety of odors. After all, each aroma consists of a large number of components, so many receptors are activated at once. As soon as odorous molecules bind to the olfactory receptors, this triggers a chain of reactions in the nerve endings, and a signal is generated that is also sent to the brain.

Now about temperature receptors, which are also very important. Why does mint give you a feeling of freshness, but pepper burns your tongue? The menthol found in mint activates the TRPM8 receptor. This cation channel, discovered in 2002, begins to work when the temperature drops below 37 o C - that is, it is responsible for the formation of the feeling of cold. Menthol lowers the temperature threshold for activation of TRPM8, so when it enters the mouth, a cold sensation occurs at a constant ambient temperature. Capsaicin, one of the components of hot pepper, on the contrary, activates heat receptors TRPV1 - ion channels similar in structure to TRPM8. But unlike cold weather, TRPV1 are activated when the temperature rises above 37 o C. This is why capsaicin causes a burning sensation. The piquant tastes of other spices - cinnamon, mustard, cumin - are also recognized by temperature receptors. By the way, the temperature of food is of great importance - the taste is maximally expressed when it is equal to or slightly higher than the temperature of the oral cavity.

Oddly enough, teeth are also involved in the perception of taste. The texture of food is reported to us by pressure sensors located around the roots of the teeth. The chewing muscles, which “assess” the hardness of food, also take part in this. It has been proven that when there are many teeth in the mouth with the nerves removed, the sense of taste changes.

In general, taste is, as doctors say, a multimodal sensation. The following information must be brought together: from chemical selective taste receptors, thermal receptors, data from mechanical sensors of teeth and chewing muscles, as well as olfactory receptors, which are affected by volatile food components.

In about 150 milliseconds, the first information about taste stimulation reaches the central cerebral cortex. Delivery is carried out by four nerves. The facial nerve transmits signals coming from the taste buds, which are located on the front of the tongue and on the roof of the mouth, the trigeminal nerve transmits information about texture and temperature in the same area, and the glossopharyngeal nerve transmits taste information from the back third of the tongue. The vagus nerve transmits information from the throat and epiglottis. The signals then pass through the medulla oblongata and end up in the thalamus. It is there that taste signals connect with olfactory signals and together go to the taste zone of the cerebral cortex (Fig. 3).

All information about a product is processed by the brain simultaneously. For example, when there is a strawberry in the mouth, it will be a sweet taste, a strawberry smell, a juicy texture with seeds. Signals from the senses, processed in many parts of the cerebral cortex, are mixed to produce a complex picture. After a second we already understand what we are eating. Moreover, the overall picture is created by the nonlinear addition of the components. For example, the acidity of lemon juice can be masked with sugar, and it will seem less sour, although its proton content will not decrease.

Small and big

Young children have more taste buds, which is why they perceive everything so keenly and are so picky about food. What seemed bitter and disgusting in childhood is easily swallowed with age. In older people, many of the taste buds die off, so food often seems bland to them. There is an effect of getting used to the taste - over time, the severity of the sensation decreases. Moreover, addiction to sweet and salty foods develops faster than to bitter and sour foods. That is, people who are used to heavily salting or sweetening their food do not feel salt and sugar. There are other interesting effects. For example, getting used to bitter increases sensitivity to sour and salty, and adaptation to sweet sharpens the perception of all other tastes.

The child learns to distinguish smells and tastes already in the womb. By swallowing and inhaling amniotic fluid, the embryo masters the entire palette of smells and tastes that the mother perceives. And even then he forms the passions with which he will come into this world. For example, pregnant women were offered sweets with anise ten days before giving birth, and then they watched how the newborns behaved in the first four days of life. Those whose mothers ate anise sweets clearly distinguished this smell and turned their heads in its direction. According to other studies, the same effect is observed with garlic, carrots or alcohol.

Of course, taste preferences strongly depend on family food traditions, on the customs of the country in which a person grew up. In Africa and Asia, grasshoppers, ants and other insects are tasty and nutritious food, but in Europeans they cause a gag reflex. One way or another, nature has left us a little room for choice: exactly how you will experience this or that taste is largely predetermined genetically.

Genes dictate the menu

Sometimes it seems to us that we ourselves choose what food we like, or, in extreme cases, that we eat what our parents taught us to eat. But scientists are increasingly inclined to believe that genes make the choice for us. After all, people taste the same substance differently, and the thresholds of taste sensitivity in different people also differ greatly - up to “taste blindness” to individual substances. Today, researchers are seriously asking the question: Are some people really programmed to eat French fries and gain weight, while others happily eat boiled potatoes? This is especially concerning in the United States, which is facing a real obesity epidemic.

The question of the genetic predetermination of smell and taste was first raised in 1931, when DuPont chemist Arthur Fox synthesized the odorous molecule phenylthiocarbamide (PTC). His colleague noticed a pungent odor that came from the substance, much to the surprise of Fox, who did not smell anything. He also found the substance tasteless, while the same colleague found it very bitter. Fox checked the FTC on all members of his family - no one smelled...

This 1931 publication spawned a number of sensitivity studies - not only to PTC, but to bitter substances in general. Approximately 50% of Europeans were insensitive to the bitterness of phenylthiourea, but only 30% of Asians and 1.4% of Amazon Indians. The gene responsible for this was discovered only in 2003. It turned out that it encodes a receptor protein of taste cells. In different individuals, this gene exists in different versions, and each of them encodes a slightly different receptor protein - accordingly, phenylthiourea may interact with it well, poorly, or not at all. Therefore, different people perceive bitterness to varying degrees. Since then, about 30 genes encoding bitter taste recognition have been discovered.

How does this affect our taste preferences? Many people try to answer this question. It seems to be known that those who detect the bitter taste of FTC have an aversion to broccoli and Brussels sprouts. These vegetables contain molecules whose structure is similar to FTC. Professor Adam Drewnowski of the University of Michigan in 1995 formed three groups of people based on their ability to recognize a compound similar to FTC, but less toxic, in a solution. The same groups were tested for taste preferences. Those who sensed very small concentrations of the test substance found the coffee and saccharin too bitter. Regular sucrose (sugar that comes from cane and beets) seemed sweeter to them than to others. And the hot pepper burned much more strongly.

The question of the taste of fat remains controversial. For a long time, it was believed that we recognize fat through our sense of smell because lipids release odorous molecules and also due to a certain texture. Nobody even looked for special taste buds for fat. These ideas were shaken in 1997 by the research group of Toru Fushiki from Kyoto University. From the experiment it was known that the rat pups preferred the food bottle containing fats. To test whether this was due to consistency, Japanese biologists gave rodents without a sense of smell two solutions - one with lipids, and the other with a similar consistency, simulated thanks to a thickener. The rats unmistakably chose the solution with lipids - apparently guided by taste.

In fact, it turned out that the tongue of rodents can recognize the taste of fat using a special receptor - the glycoprotein CD36 (fatty acid transporter). French researchers led by Phillipe Benard have proven that when the gene encoding CD36 is blocked, the animal ceases to give preference to fatty foods, and in the gastrointestinal tract, when fat gets on the tongue, there is no change in secretion. At the same time, the animals still preferred sweets and avoided bitter ones. This means that a specific receptor for fat was found.

But a person is not a rodent. The presence of the CD36 transport protein in our body has been proven. It transports fatty acids to the brain, heart, and is produced in the gastrointestinal tract. But is it on the tongue? Two laboratories, American and German, have tried to clarify this issue, but there are no publications yet. Studies in African Americans, who have a high diversity of the gene encoding the CD36 protein, seem to indicate that the ability to recognize fat in food is indeed associated with some modifications of a particular gene. It is hoped that once the question "can our tongues taste fat" is answered, doctors will have new options for treating obesity.

Gourmet animals?

In the 19th century, the famous French gastronomer and author of the widely cited book “The Physiology of Taste,” Jean-Anthelme Brillat-Savarin, insisted that only homo sapiens experiences pleasure from food, which is actually needed simply to maintain life. Indeed, modern research has shown that animals perceive taste differently than we do. But is the sense of taste so different between humans and other representatives of the primate order?

Experiments were carried out on 30 species of monkeys, which were given to taste pure water and solutions with different tastes and different concentrations: sweet, salty, sour, bitter. It turned out that their taste sensitivity greatly depends on who is trying what. Primates, like us, taste sweet, salty, sour and bitter. The monkey distinguishes fruit fructose from beet sucrose, as well as tree bark tannins. But, for example, the Uistiti, a breed of monkey that eats leaves and greens, is more sensitive to alkaloids and quinine in tree bark than the fruit-eating primates of South America.

Together with American colleagues from the University of Wisconsin, French researchers also confirmed this with electrophysiological experiments and brought together the picture obtained on different species of monkeys. In electrophysiological experiments, the electrical activity of the fibers of one of the taste nerves was recorded, depending on what product the animal was eating. When electrical activity was observed, it meant that the animal was tasting the food.

How is it going for humans? To determine sensitivity thresholds, volunteers were blindly allowed to taste first very dilute and then increasingly concentrated solutions until they clearly formulated what the solution tasted like. The human “taste tree” is generally similar to those obtained for monkeys. In humans, taste sensations are also far apart in opposite directions from what brings energy to the body (sugar) and what can harm (alkaloids, tannin). There is also a correlation between substances of the same type. Someone who is very sensitive to sucrose has a chance of also being sensitive to fructose. But there is no correlation between sensitivity to quinine and tannin, and someone sensitive to fructose is not necessarily sensitive to tannin.

Since we and monkeys have such similar mechanisms of taste, does this mean that we are very close on the evolutionary tree? According to the most plausible version, by the end of the Paleozoic and the appearance of the first terrestrial creatures, the evolution of plants and animals proceeded in parallel. The plants had to somehow resist the active ultraviolet radiation of the young sun, so only those specimens that had enough polyphenols for protection were able to survive on land. These same compounds protected plants from herbivores because they were toxic and difficult to digest.

Vertebrates have evolved the ability to detect bitter or astringent tastes. It was these tastes that surrounded primates when they appeared in the Cenozoic era (Eocene), and then the first people. The emergence of plants with flowers that turned into fruits with sweet pulp played a large role in the evolution of taste. Primates and fruiting plants co-evolved: primates ate sweet fruits and dispersed their seeds to promote the growth of trees and vines in tropical forests. But the ability to recognize the taste of salt (especially table salt) could hardly have arisen during coevolution with plants. Perhaps it came from aquatic vertebrates, and primates simply inherited it.

I wonder if primates, when choosing food, are guided only by nutritional value and taste? No, it turns out that they can eat plants for medicinal purposes. Michael Huffman of Kyoto University observed a chimpanzee with stomach problems in 1987 in western Tanzania. The monkey ate the stems of a bitter plant Vernonia amygdalina(vernonia), which chimpanzees do not usually eat. It turned out that the shoots of the tree contain substances that help against malaria, dysentery and schistosomiasis, and also have antibacterial properties. Observing the behavior of wild chimpanzees gave scientists food for thought: new herbal medicines were created.

In general, the taste has not changed much during evolution. Both primates and humans enjoy the taste of sweets - endorphins are produced in their bodies. Therefore, perhaps the great French culinary specialist was not entirely right - primates can also be gourmets.

Based on materials from the magazine
"La Recherche", No. 7-8, 2010

Smell is one of the senses a person needs to live a full life. And its violations impose tangible restrictions on the emotional state and become a real problem. Among olfactory disorders, there are also those when the patient is haunted by a smell that is not actually there. Everyone is interested in the question of the origin of unpleasant symptoms, but only a doctor can help determine the source of disorders in the body.

Smell is perceived through the reaction of the olfactory receptors located in the mucous membrane of the nasal cavity to certain aromatic molecules. But this is only the initial section of the corresponding analyzer. Next, the nerve impulse is transmitted to the areas of the brain responsible for the analysis of sensations (temporal lobes). And when a person smells odors that are not there, this clearly indicates some kind of pathology.

First of all, you should divide all the reasons into two groups. The smell may be very real, but is not felt by others until the patient speaks to them at close range. This is likely in the following situations, covering the practice of ENT doctors and dentists:

• Fetid runny nose (ozena).
• Sinusitis (sinusitis, sinusitis).
• Chronic tonsillitis.
• Caries, pulpitis, periodontitis.

These diseases are accompanied by the formation of pus, which gives an unpleasant odor. A similar situation may occur in those who suffer from diseases of the gastrointestinal tract (gastritis, peptic ulcer, cholecystitis and pancreatitis). Food that enters the digestive tract is processed less well, and during belching or reflux, molecules of unpleasant aroma come out. A similar problem may not be noticeable to others unless they get close.

Some people have a lower olfactory threshold. They smell better than others, so sometimes they encounter misunderstandings from others. Some aroma may be too weak to be detected by anyone else. And this feature should also be taken into account by the doctor.

A separate group of causes are those that are associated with damage to any of the sections of the olfactory analyzer. The emerging odors do not reach others, since their formation, transmission and analysis in a particular person are disrupted. And although the basis for an unpleasant aroma may be some other (quite real) one, the final result is present only in the patient’s mind and poses a problem specifically for him.

There are quite a lot of conditions manifested by impaired sense of smell (dysosmia or parosmia). They include both respiratory pathology with inflammation of the nasal mucosa, for example, rhinitis or ARVI, and other disorders in the body:

• Hormonal changes (during pregnancy, during menstruation or menopause).
• Bad habits (smoking, alcohol abuse, drugs).
• Taking certain medications and chemical poisoning.
• Endocrine disorders (hypothyroidism, diabetes mellitus).
• Systemic diseases (scleroderma).
• Traumatic brain injuries.
• Brain tumors.
• Neuroses or depression.
• Psychosis (schizophrenia).
• Epilepsy.

It is also necessary to remember about the so-called phantom odors, which are associated with some kind of stress in the past and left a strong impression. In similar situations they can come to the surface. As you can see, the source of the unpleasant odor can be hidden among a large number of diseases. And some can be quite serious. But you shouldn’t immediately get scared and look for a dangerous pathology - the causes of the disorders will become clear only after a thorough examination.

Why people imagine certain smells is a rather serious question and requires further research.

Symptoms

Any pathology has certain signs. To identify them, the doctor evaluates the patient's complaints, analyzes the factors that precede the appearance of an unpleasant odor, and conducts a physical examination. You should understand when an extraneous odor is felt, whether it is constantly present or occurs periodically, how intense it is, what contributes to its disappearance, and what additional symptoms are present in the clinical picture. Sometimes this alone makes it possible to establish the cause of dysosmia, but not always.

The aroma that haunts the patient may have different colors. Those who drink citrus tea often feel a foreign burning smell, and hot spices can cause a feeling of the presence of sulfur in them. Simultaneously with the distortion of smell, taste also changes, since they are closely related. A bad runny nose, for example, can create the illusion that onions have become sweet and smell like apples.

ENT pathology

The first thing you should think about when complaining of an unpleasant odor is diseases of the ENT organs. When the nasal mucosa is damaged, the sense of smell is invariably impaired, but the patient may not always feel the smell of pus or rot. Most often, such a symptom occurs with sinusitis, chronic tonsillitis or ozena. In the latter case, the smell is so pronounced that others notice it. But besides this, you need to pay attention to other symptoms:

• Impaired nasal breathing.
• Nasal discharge (mucopurulent or purulent).
• Heaviness in the projection of the paranasal sinuses.
• Dry mucous membranes and crusting.
• Sore throat when swallowing.
• Traffic jams on the tonsils.

If we are talking about acute sinusitis, then the purulent process in the sinuses invariably entails an increase in temperature and intoxication with headaches, but chronic sinusitis gives less pronounced symptoms. With tonsillitis, disorders of the kidneys, heart, and joints are often detected (the result of sensitization to streptococcal antigens). If the sense of smell is impaired due to ARVI, then in the clinical picture, in addition to a runny nose, against the background of intoxication there will be other catarrhal symptoms, for example, redness of the throat and lacrimation.

Pathology of the nose, paranasal sinuses and pharynx is the main cause of the appearance of a foreign odor, which can be perceived by others only upon close contact with the patient.

Digestive tract diseases

An unpleasant odor can also haunt those who suffer from diseases of the gastrointestinal tract. Impaired digestion of food is the main mechanism of this symptom. The smell of rotten eggs is disturbing in hypoacid gastritis (with reduced acidity) or duodenal ulcer; it does not appear constantly, but after eating. The clinical picture also contains other signs of dyspeptic syndrome:

• Belching.
• Nausea.
• Bloating.
• Changing the stool.

Many people feel discomfort in the stomach or pain in the epigastrium. And concomitant gastroesophageal reflux causes heartburn and further esophagitis. If the gallbladder is affected, then an additional symptom will be a feeling of bitterness in the mouth.

Psychoneurological problems

Many patients with neuropsychiatric status disorders perceive an odor that is not really there. It can have either a real prototype (illusion) or be based on non-existent connections (hallucination). The first situation can also arise in a healthy person who has suffered severe emotional stress, but it often becomes a constant companion for those who suffer from neurosis or depression. Additional symptoms of the pathology are:

• Decreased mood.
• Emotional lability.
• Irritability and anxiety.
• Feeling of a “lump” in the throat.
• Sleep disorders.

Characteristic signs will also be somatic functional disorders that arise due to an imbalance of nervous regulation (increased heart rate, increased sweating, nausea, shortness of breath, etc.). Unlike neurotic reactions, psychoses are accompanied by profound changes in the personal sphere. Then there are various hallucinations (auditory, visual, olfactory), overvalued and delusional ideas, when the perception of the surrounding world and behavior are disrupted, and there is no critical understanding of what is happening.

The feeling that you suddenly began to smell like rotten meat can occur with epilepsy. Olfactory and gustatory hallucinations are a kind of “aura” that precedes a convulsive attack. This indicates the location of the focus of pathological activity in the temporal lobe cortex. After a few seconds or minutes, the patient develops a typical attack with clonic-tonic convulsions, short-term loss of consciousness, and tongue biting. A similar picture also occurs with a brain tumor of the corresponding localization or skull injuries.

Neuropsychic disorders, as a cause of foreign odor, are perhaps the most serious situation that cannot be ignored.

Additional diagnostics

Smells that others cannot smell are a reason for a detailed examination. It is possible to find out the cause of what is happening only on the basis of a comprehensive diagnosis using a laboratory and instrumental complex. Based on the doctor’s assumption based on the clinical picture, the patient is recommended to undergo additional procedures:

• General blood and urine analysis.
• Blood biochemistry (inflammatory markers, liver tests, electrolytes, glucose, hormonal spectrum).
• Nasal and throat swab (cytology, culture, PCR).
• Rhinoscopy.
• X-ray of the paranasal sinuses.
• Computed tomography of the head.
• Echoencephalography.
• Fibrogastroscopy.
• Ultrasound of the abdominal organs.

To obtain maximum diagnostic value, the examination program is developed on an individual basis. If necessary, the patient consults not only an ENT doctor, but also other specialists: gastroenterologist, neurologist, endocrinologist, psychotherapist. And the results obtained make it possible to establish the final cause of the violations and eliminate the unpleasant odor that seemed to patients.

A person studies the world around him, draws information from it thanks to the ability to see, hear, touch, and also smell and taste. If the function of one of the sense organs is impaired, the quality of life is significantly reduced. For example, delicious, fresh food brings pleasure and pleasure. It is very important that the ability to perceive taste is necessary for identifying the food consumed, assessing its quality, and helps a person eliminate the consumption of spoiled foods that are hazardous to health.

It often happens that this ability is impaired and a person ceases to feel the taste of food. This condition is called hypogeusia. Most often, this goes away quickly without additional medical intervention.
However, in some cases, hypogeusia is a manifestation of pathological processes in the body and is a symptom of a serious disease. You can’t do this without the help of a doctor.

Let's talk on the www.site about the reasons for the loss of taste of food, the reasons, what to do, how hypogeusia is treated. Let's start our conversation with the most common reasons for this phenomenon:

Loss of taste - reasons

Most often, a change, disturbance, or loss of taste in the mouth occurs as a result of smoking tobacco, which dries out the tongue, affecting the taste buds. Very often the cause is alcoholism and drug use.

Taking certain medications has an effect, in particular lithium, penicillamine, rifampicin, as well as captopril, vinblastine, antithyroid drugs, etc.

Causes associated with pathological conditions:

Damage, changes in the tissues of the taste bud, as well as dysfunction of the receptor cells that make up the epithelium of the tongue (sensory disorders).

Pinching, injury to the nerve on which the identification of tastes depends. Facial nerve paralysis. This pathological condition is characterized by increased salivation, loss, and taste disturbances.

Trauma to the skull, namely, a fracture of its base when the cranial nerve is damaged. In this case, partial agenesis (loss of taste) often occurs - a person loses the ability to distinguish most mixed tastes, except for simple ones: salty, sour, bitter, sweet.

Viral colds and infectious diseases.

Benign tumors, oncological diseases of the oral cavity. These pathologies destroy taste buds.

Fungal diseases of the oral mucosa (thrush).

Sjögren's syndrome is a serious genetic disease.

Acute form of viral hepatitis.

Side effects from radiation therapy.

Lack of vitamins (minerals), especially zinc.

If there is a loss of taste, what to do about it?

Drug treatment

In case of persistent, long-term violation, you should consult a doctor who will prescribe an examination to determine the cause of the violation. If an underlying disease is detected, treatment will be carried out by an appropriate specialist. Once the root cause is eliminated, the taste will be restored.

For example, in the presence of an inflammatory or infectious disease, the patient is prescribed therapy using antibiotics: rhithromycin, caltopril or methicillin, etc.

In case of hypovitaminosis, the necessary preparations of vitamins and minerals are prescribed. For example, if you have a zinc deficiency, it is recommended to take the drug Zincteral.

If loss of taste in food occurs while taking medications, this medicine is changed to another from the same group. If this is not possible, the doctor will change the dosage and treatment regimen.

You can restore normal taste sensations with the help of medication. For example, according to indications, the doctor may prescribe an artificial saliva substitute, or a drug that stimulates its production. To eliminate the disorder and additionally moisturize the oral cavity, the drug Hyposalix is ​​often used.

Loss of taste - prevention

To avoid the development of hypogeusia, it is enough to follow simple rules:

Quit smoking, alcohol, drugs, lead a healthy lifestyle.

Eat properly, fortified foods without dyes, flavor enhancers, etc.

Do not eat food or drinks that are too hot or too cold.

Follow the rules of personal hygiene, in particular, when brushing your teeth every day, be sure to clean the surface of your tongue.

We talked about why loss of taste in food occurs, and what treatment helps with this. You also need to remember that any taste sensation is associated with various factors: psychological, emotional or physiological. Therefore, at different periods a person can experience both pleasure from food and aversion to it. Under certain circumstances, we generally absorb food without feeling its taste. So these factors also need to be taken into account. Be healthy!