home Audience 4 Loss of taste in food - reasons, what to do, treatment. Anatomy of taste Why does a person need to feel an unpleasant taste?

Loss of taste in food - reasons, what to do, treatment. Anatomy of taste Why does a person need to feel an unpleasant taste?

In his daily life, a person quite often encounters such an incident as a taste disorder (hypogeusia).

It can be short-term (for example, you put too hot food in your mouth and you stop feeling taste for some time) or long-term - it can be a consequence of deeper disorders in the human body, or one of the symptoms of a serious illness.

ICD-10 code

R43 Impaired sense of smell and taste

Causes of taste disturbance

This diagnosis is made to the patient when the patient is unable to ascertain the taste of any product:

If the damage has affected the taste buds. Doctors refer to this pathology as transport losses.
If the pathology damages the receptor cells. Doctors classify it as sensory impairment.
Damage to taste caused by pathology of the afferent nerve or malfunction of the central taste analyzer. This pathology can be attributed to neural changes.

What are the causes of taste disturbance:

Symptoms of taste disturbance

Before moving on to a more detailed introduction to this disease, let's define the terminology. Based on clinical studies and based on patient complaints, doctors classify symptoms of taste disturbance into certain categories:

General ageusia is a problem in recognizing simple basic tastes (sweet, bitter, salty, sour tastes).
Selective ageusia is difficulty in recognizing certain flavors.
Specific ageusia is a decreased sensitivity of taste to certain substances.
General hypogeusia is a violation of taste sensitivity, which manifests itself in the case of all substances.
Selective hypogeusia is a taste disorder that affects certain substances.
Dysgeusia is a perverted manifestation of taste preferences. This is either an incorrect taste sensation of a specific substance (sour and bitter tastes are often confused). Or a somatically imposed perception of tastes against the background of absent taste stimuli. Dysgeusia can develop both on a semantic basis and in pathology at the physiological or pathophysiological level.

Forms

Impaired sense of smell and taste

There are quite rare cases when, with a particular disease, a patient is diagnosed with either only a taste disorder, or, individually, a disorder of smell. This is rather an exception to the rule. Much more often, in most diagnosed cases, disorders of smell and taste go hand in hand. Therefore, if a patient complains of loss of taste, the attending physician must also examine his sense of smell.

Such an interrelated disorder rarely leads to disability and is not life-threatening, but a violation of taste and smell can greatly reduce the quality of social life. Often these changes, especially in older people, can lead to apathy, loss of appetite and, ultimately, exhaustion. Losing your sense of smell can also lead to dangerous situations. For example, the patient simply will not feel the odorant (flavored fragrance) that is specially mixed into natural gas. As a result, it does not recognize a gas leak, which can lead to tragedy.

Therefore, before declaring the symptoms to be harmless, the attending physician must exclude underlying, systemic diseases. Since hyperosmia (increased sensitivity to odors) can manifest itself as one of the symptoms of diseases of a neurotic nature, and dysosmia (perverted sense of smell) - with the infectious genesis of the disease.

Adequate perception of taste in a person occurs when all groups of receptors work in the recognition process: facial, glossopharyngeal, as well as receptors of the vagus nerves. If at least one of these groups, due to reasons, falls out of the examination, the person receives a taste disorder.

Taste receptors are distributed over the surface of the oral cavity: the palate, tongue, pharynx and pharynx. When irritated, they send a signal to the brain and the brain cells recognize this signal as taste. Each group of receptors is “responsible” for one of the basic tastes (salty, bitter, sweet, sour) and only when working together in a complex manner are they able to recognize the nuances and subtleties of taste shades.

Doctors include age-related changes (decrease in the number of taste buds), smoking, which dries out the mucous membrane (taste is better recognized in a liquid medium) as non-pathological causes of impaired taste and smell.

Diagnosis of taste disorders

Before proceeding with diagnosis, it is necessary to clearly identify the case when the patient not only finds it difficult to determine the taste of the product, but also suffers from a pathology of smell.

First of all, the specialist tests taste sensitivity throughout the entire oral cavity, determining its threshold for manifestation. The patient is asked in turn to determine the taste of citric acid (sour), table salt (salty), sugar (sweet) and quinine hydrochloride (bitter). The test results form the clinical picture and extent of the lesion.

The qualitative threshold of sensations in certain language areas is checked by applying a few drops of the solution to certain areas of the oral cavity. The patient swallows and shares his feelings, but the characteristics are given differentiated, for each area separately.

Today, research methods such as electrometric ones have appeared, but they do not paint a sufficiently clear, reliable picture of perception, so the diagnosis of taste disorders is carried out the old fashioned way, with clinical taste tests.

As in the case of pathology of smell, in case of taste disturbance, at the moment, there are no precise methods that can categorically differentiate the causes of a sensory, transport or neural nature. In order for the doctor to be able to more specifically determine the cause of the neurological disorder, it is necessary to localize the location of the lesion as accurately as possible. The patient's medical history also provides important information for the attending physician. It is necessary to exclude genetically transmitted endocrine diseases.

It is also necessary to investigate the side effects of drugs if the patient is being treated for another disease. In this case, the attending doctor will either prescribe another drug with the same effect, or change the dosage of the first one.

Computed tomography is also performed. It will provide a clinical picture of the condition of the sinuses and medulla. It is necessary to exclude or confirm the presence of systemic diseases. Diagnostics of the oral cavity will help determine possible local causes (diseases) that can lead to taste disturbances: malfunction of the salivary glands, otitis media, prosthetic teeth in the upper jaw, and others.

The doctor is also interested in whether the patient has traumatic brain injuries, laser irradiation of the head and neck area, or diseases associated with inflammatory processes of the central nervous system and cranial nerves.

The attending physician also establishes the chronology of the occurrence of the disease, injury or surgical intervention with the appearance of taste disturbance. It is necessary to understand whether the patient has contact with toxic chemicals?

For women, important information is the onset of menopause or recent pregnancy.

Laboratory tests are also carried out. They are able (detailed blood test) to give an answer whether there are foci of infectious lesions or manifestations of an allergic nature, anemia, or blood sugar levels (diabetes mellitus) in the patient’s body. Carrying out special tests will allow you to recognize liver or kidney pathologies. And so on.

If there are any suspicions, the attending physician refers his patient for consultation with a specialized specialist: otolaryngologist, dentist, endocrinologist, neurologist, and so on. And in the presence of a traumatic brain injury, the patient undergoes an X-ray, as well as a CT or MRI of the head, which will help identify intracranial changes or disorders of the cranial nerves.

Treatment of taste disorders

First of all, the treatment of taste disturbance is the elimination of the cause of its occurrence, that is, it is a set of measures that lead to the relief or complete eradication of the disease that led to this pathology

Treatment can begin not after the doctor has identified a taste disorder, but after the source and cause of this pathology have been fully established.

If the cause of taste disturbances is a drug that the patient takes during treatment, then the attending physician, after the patient’s complaints, will either change the drug to another of the same group, or change the dosage of the first one if it is impossible to replace it.

In any case, if the problem exists and has not yet been solved, or the composition of the secretions has changed, artificial saliva is used.

"Hyposalix"

This medication is used to moisturize the oral cavity, which will completely or partially restore the taste disturbance that has occurred.

The solution is sprayed into the mouth while the patient is sitting or standing. The medical spray is alternately directed to the inside of one or the other cheek. Spraying is carried out with a single press. The number of daily repetitions is six to eight times. It is not limited to a time frame, but is sprayed as needed - if the patient begins to feel dry mouth. This drug is non-toxic, it can be safely used by pregnant women and small children, there are no contraindications during lactation.

If the source of the problem is bacterial and fungal diseases, the treatment protocol for such a patient will consist of drugs that can inhibit harmful pathogenic flora.

Erythromycin

Daily dose of the drug:

for newborns under three months of age – 20-40 mg;
children from four months to 18 years – 30-50 mg per kilogram of the child’s weight (in two to four doses);
for adults and adolescents who have crossed the threshold at 14 years - 250 - 500 mg (one-time dose), repeated dose no earlier than 6 hours later, the daily dosage can be increased to 1-2 g, and in severe forms of the disease up to 4 g.

When taking this drug, some side effects may occur: nausea, vomiting, dysbacteriosis and diarrhea, dysfunction of the liver and pancreas, and others. This drug is contraindicated during lactation, as it penetrates well into breast milk and can enter the newborn’s body with it. As well as increased hypersensitivity to substances that are part of the medication.

Captopril

If the cause of taste disturbance is a malfunction of the kidneys, the doctor prescribes a daily dose (for a non-severe form of the disease) of 75–100 mg. For more severe manifestations of the disease, the daily dose is initially reduced to 12.5-25 mg and only after some time the attending physician gradually begins to increase the amount of the drug. For elderly people, the doctor selects the dosage individually, starting from 6.25 mg, and you must try to keep it at this level. Reception is carried out twice a day.

This drug is not recommended for use if there is an intolerance to one or more of the components included in the drug, as well as in cases of obvious disturbances in the functioning of the liver and kidneys. Take very carefully, only under the supervision of a doctor, to persons with a history of cardiovascular diseases. Not recommended for children under 18 years of age, as well as for pregnant and nursing mothers.

Methicillin

Or the scientific name is methicillin sodium salt. It is prescribed only intramuscularly.

The drug solution is prepared immediately before use. 1.5 ml of special water for injections, or a 0.5% novocaine solution, or a sodium chloride solution is injected into a bottle with 1.0 g of methicillin using a needle.

Adults are given an injection every four to six hours. In case of severe manifestations of the disease, the dosage of the drug can be increased from one to two grams.

For infants (up to 3 months), the daily dosage is 0.5 g.

For children and adolescents under 12 years of age, this drug is prescribed per kilogram of the child’s weight - 0.025 g. Injections are given after six hours.

Children who have crossed the 12-year mark - 0.75–1.0 g of methicillin sodium salt in solution every six hours, or the adult dosage.

The course of treatment is dictated by the severity of the disease.

Limit the use of this drug to persons suffering from individual intolerance to penicillin.

Ampicillin

Taking this medication is not dependent on food intake. An adult can take 0.5 g once, but the daily dosage can be indicated as 2 - 3 g. For children under four years of age, the daily dosage is calculated per kilogram of the baby’s weight and is 100–150 mg (divided into four to six doses). The course of treatment is individual, prescribed by the attending physician and lasts from one to three weeks.

This drug is quite insidious in terms of side effects: gastrointestinal tract (exacerbation of gastritis), stomatitis, dysbacteriosis, diarrhea, nausea with vomiting, sweating, abdominal pain and many others. This drug is contraindicated in children under three years of age; with increased sensitivity to the components of the drug, pregnant women and breastfeeding mothers.

Such patients are also required to be prescribed immunostimulants in order to push the patient’s body to resist the disease.

Immunal

The solution is prepared immediately before use by diluting the solution with a small amount of boiled water. The dosage is individual and designed for each age. Take orally, three times a day.

Children from one to six years old - 1 ml of solution.
Adolescents aged six to 12 years – 1.5 ml.
Adults and adolescents over 12 years old – 2.5 ml.

The medicine can also be taken in tablets:

Children from one to four years old. Crush one tablet and dilute with a small volume of water.
Children from four to six years old - one tablet one to two times a day.
Adolescents from six to 12 years old - one tablet one to three times a day.
Adults and adolescents over 12 years of age – one tablet, three to four doses per day.

The course of treatment is at least one week, but no more than eight.

Immunal is contraindicated for use in the following cases: children under one year old (when taking solution) and up to four years old (when taking tablets), hypersensitivity to the components of the drug, as well as plants of the Asteraceae family; for tuberculosis; leukemia; HIV infections and others.

Timalin

It is administered intramuscularly. The solution is prepared immediately before injection: the volume of one bottle is diluted with 1 - 2 ml of isotonic sodium chloride solution. The mixture is shaken until completely dissolved.

The drug is administered:

toddler up to one year - 5 - 20 mg. Daily.
For a child one to three years old - 2 mg throughout the day.
Preschoolers four to six years old – 3 mg.
Teenagers seven - 14 years old - 5 mg.
Adults – 5 – 20 mg daily. The general treatment course is 30 – 100 mg.

Duration of treatment is from three to ten days. If necessary, treatment can be repeated after a month.

This drug does not have any special contraindications, except for individual intolerance to its components.

If the cause of the taste disorder is a zinc deficiency in the body, then the patient, apparently, will only need to drink some kind of zinc preparation. For example, zinkteral.

Zincteral

A tablet that should not be chewed or split. Adults should take it one hour before meals three times a day, or two hours after meals. Gradually, as taste perception is restored, the dosage can be reduced to one tablet per day. For children over four years of age, the dosage is one tablet per day. There are practically no contraindications for this drug, except for hypersensitivity to the components that make up the drug.

If it turns out that the cause of the loss of taste perception is smoking, then you will have to rip out one thing: either smoke and not feel the delights of taste, or quit smoking and regain the “taste of life”.

Prevention

It is quite difficult to decide on preventive measures if the cause of taste disturbance can be such a huge number of diseases that are different in both genesis and severity. And yet, prevention of taste disorders is possible.

Maintaining a healthy lifestyle. For example, smoking or alcohol can be one of the reasons for a violation of taste preferences.
Increasing the quantity and variety of spices consumed. Excellent training of the receptor apparatus.

Don't forget about personal hygiene:

Brushing your teeth morning and evening.
The toothbrush and toothpaste must be selected correctly.
Rinsing the mouth after each meal, which, if not removed, begins to rot, creating favorable conditions for the development of pathogenic bacteria.
You should wash your hands not only before eating, but also after visiting the toilet, and upon coming home from the street.
Preventive visits to the dentist. Complete sanitation of the oral cavity is a good barrier in the fight against infectious and fungal diseases.
The diet should be harmoniously balanced. It must contain a sufficient amount of minerals and vitamins.
If necessary, as prescribed by the doctor, you must take zinc and iron supplements.
If the disease does occur, it must be treated “without delay,” and the course must be completed to the end, thereby eliminating all the causes of taste disturbance.

Incredible facts

Taste is not only one of the most pleasant, but also a rather complex sensation that science is only beginning to understand.

Here are some surprising facts about your ability to taste.

Sensations of taste

1. Each of us has a different number of taste buds

We have several thousand taste buds in our mouth, but this number varies from 2,000 to 10,000 in different people. Taste buds are located not only on the tongue, but also on the roof of the mouth and the walls of the mouth, throat and esophagus. As you age, your taste buds become less sensitive, which likely explains why foods you disliked as a child become palatable as an adult.

2. You taste with your brain.

When you bite into a piece of pie, your mouth feels like it's filled with flavor sensations. But most of these sensations originate in your brain.

Cranial nerves and taste buds send food molecules to the olfactory nerve endings in the nose. These molecules send signals to an area of the brain known as the primary taste cortex.

These messages, combined with odor messages, produce the sensation of taste.

Why do people taste the same taste differently?

Why

Loss of taste

3. You can't taste well if you can't smell.

Most of the sensations of taste are smells transmitted to the smell receptors in your brain. Inability to smell due to a cold, smoking, or certain side effects of medications can affect the smell receptors in the brain, making it difficult for you to taste.

4. Sweet foods make meals memorable.

A new study has found that centers associated with episodic memory in the brain are activated when we eat sweets. Episodic memory is a type of memory that helps you remember what you experienced at a certain time in a certain place. Episodic memory can help control eating behavior, such as making decisions based on memories of what and when we eat.

5. Taste can be turned off

Scientists have learned to stimulate and silence neurons in the brain responsible for the basic taste sensations: sweet, sour, salty, bitter and umami. For example, in an experiment on mice, when they stimulated bitter taste, the mice winced.

6. You can change your taste sensations yourself

Taste buds are sensitive to certain compounds in foods and medications, which can alter your ability to perceive basic taste sensations.

For example, sodium lauryl sulfate in most toothpastes, it temporarily suppresses sweetness receptors, making orange juice drunk immediately after brushing your teeth taste like unsweetened lemon juice. Also, the compound cynarin in artichokes can temporarily block sweet receptors.

Taste perception

7. The smell of ham makes food taste salty.

There is an entire industry dedicated to making the food you buy in the store taste like. The phenomenon of “phantom aroma” causes us to associate foods with a certain taste. So, for example, adding the smell of ham to food will make your brain perceive it as saltier than it actually is, since we associate ham with salt. And by adding vanilla to food, you will perceive the product as sweeter.

8. We prefer spicy food while flying.

A noisy environment, such as when you're on an airplane, can change your sense of taste. The study showed that on an airplane, people's sweet receptors are suppressed and the receptors for the "fifth taste" - umami - are enhanced. For this reason, it is more common to order food with strong flavors on an airplane. German airline Lufthansa has confirmed that passengers order tomato juice as often as beer.

9. If you're a picky eater, you might be a "supertaster."

If you can't stand the taste of eggplant or are sensitive to even the slightest presence of onions in your food, you may be one of the 25 percent of people called "supertasters," who have more taste buds on their tongues, resulting in increased taste sensitivity.

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 dimer T1R1-T1R3 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, it 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 for 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 from the University of Michigan in 1995 formed three groups of people based on their ability to recognize a compound close 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 gastronome 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 the fructose of the fruit from the sucrose of the beet, as well as the tannins of the tree bark. 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.

Interestingly, when choosing food, primates 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

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.

The same taste can be perceived differently by each of us. Some people love lemon - it seems sweet, while others simply cannot stand the sour taste of citrus fruits.

AiF.ru explains what different taste preferences depend on and why people have certain eating habits.

How many senses of taste are there really?

Even in ancient times, scientists identified only four basic tastes - bitter, sour, sweet and salty. But in the early 1900s, a Japanese scientist identified another taste. Kikunae Ikeda identified glutamic acid as the fifth taste. He called it umami, which means “pleasant spicy taste.” A person feels this taste if salts of certain organic acids are present in food. Typically these are monosodium glutamate, sodium inosinate and sodium guanylate. These substances are found in foods such as Parmesan cheese, beef, chicken, pork, mushrooms, seafood and seaweed. Some vegetables also have umami flavor: tomatoes, asparagus, cabbage and carrots.

Certain receptors located on the tongue help a person recognize taste sensations. The tongue as a whole can be roughly divided into several areas - the back part is responsible for the perception of bitter taste, the side of the tongue for sour taste, the front part for salty taste, and the tip for sweet taste. Scientists say that the back part should be responsible for the fifth taste, umami.

Taste buds. Photo: Commons.wikimedia.org

Why do we prefer a certain taste?

Sweet

Many people prefer sweet foods during periods of depression and intense mental work. Nervous and mental stress lead to faster consumption of sugar, which is why you want to eat something sweet to replenish your glucose reserves. Also, thanks to sweets, happiness hormones are formed in the body - serotonin and endorphin.

Gorkoe

Attitudes towards bitter taste may vary. The same taste may seem unbearably bitter to some, but to others it may not matter at all. But if you always want something bitter, then you have recently suffered or have not completed treatment for an illness, and craving for bitter food is a sign of residual intoxication of the body.

Salty

Scientists have found that those who crave salty foods lack certain minerals in their bodies. Such a desire may indicate severe stress that you are experiencing: due to stressful everyday life and fatigue, the body is in especially dire need of natural minerals and salts. This taste also attracts people when they are dehydrated.

Sour

One of the reasons for an addiction to sour foods is a lack of vitamin C. Therefore, a sudden desire to eat something sour can serve as a signal of an upcoming cold. The desire to taste sour foods may also indicate low stomach acidity.

Umami

Foods with umami flavor are attractive to the taste buds and can even become addictive in some people. This property of the fifth taste is used by fast food manufacturers. There is also an opinion that umami is perhaps the first taste that a person recognizes. Salts of organic acids are present in breast milk in sufficient quantities.

Why do different people perceive the same taste differently?

Different people can perceive the same taste differently. This depends on several factors.

Different number of receptors

People have different numbers of taste buds. Those who have more of them feel the taste of food more intensely. Professional wine or tea tasters, for example, have twice as many such receptors as the average person.

Aversion to a certain taste at the subconscious level

The perception of a certain taste depends on personal experience. If a person has ever been poisoned by fish, there is a chance that even the sight and smell of it will be unpleasant to him. The body will remind you that anything associated with this taste is potentially inedible.

Individual characteristics

Many people cannot eat certain foods. For some, for example, milk is a tasty and healthy product, but for others it is a taboo. The body of such people does not produce lactase, which is necessary to break down milk sugar. Also, a person’s taste sensations largely depend on the feeling of hunger - to a hungry person, tasteless food always seems tastier.

Impaired sense of smell

In addition to taste, our sense of smell also affects our sensations. With a severe runny nose, any, even your favorite dish, seems tasteless. How important the sense of smell is in the perception of taste can be understood by pinching your nose. The coffee will simply become bitter.

Diseases of internal organs

Some diseases can affect the sense of taste. For example, a feeling of bitterness in the mouth can be caused by cholelithiasis, diseases of the liver and biliary system, and the use of certain medications: antihistamines, antibiotics, St. John's wort, sea buckthorn oil.

Pregnancy

A sharp change in tastes can cause pregnancy. In this state, it is not surprising that a passionate fan of pickles can turn into a notorious sweet tooth, and a lover of chocolates, ice cream and jam suddenly wants to eat everything salty and spicy.

Genes

Sometimes it seems to us that we eat what our parents taught us to eat. But scientists are increasingly inclined to believe that genes make the choice for us. The gene responsible for bitter taste was first discovered only in 2003. It turned out that it encodes a receptor protein for taste cells. Therefore, different people perceive bitterness to varying degrees.

Cultural traditions

Taste habits are formed differently among residents of different countries. For example, some insects and grasshoppers in Africa and Asia are tasty and nutritious food, but European people find them disgusting.

Urgent problems of the body

Sudden taste preferences indicate the urgent needs of the body. Cravings for salty foods are often caused by a lack of sodium; usually you crave such food after visiting the gym. If a person suddenly starts to lean on black bread, this may mean that he lacks B vitamins, and meat lacks iron. If a person eats a lot of butter, he gets vitamin A, if he reaches for seaweed, he gets iodine. If you dream about bananas, it means your body needs magnesium.