How Taste Buds on Your Tongue Work
Thousands of taste buds send signals about taste sensation to the brain
Medically reviewed by Scott Sundick, MDMedically reviewed by Scott Sundick, MD
Taste buds on your tongue are tiny organs that help detect the five elements of taste perception: saltiness, sourness, bitterness, sweetness, and savoriness (also known as umami).
The adult tongue has between 2,000 and 4,000 taste buds, each of which is made up of 50 to 150 taste receptor cells (known as gustatory cells). These cells transmit information that the brain interprets as different flavors or tastes.
There are many conditions that can alter how you normally experience flavors, including taste disorders like burning mouth syndrome, dysgeusia, and phantom taste perception.
This article explains the function and anatomy of taste buds. It also describes conditions that affect taste and how taste disorders are diagnosed and treated.
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What Do Taste Buds Do?
The ability to perceive tastes involves a complex system of organs that work together to help detect and differentiate flavors. Taste buds, while key to this process, are not the only organs involved.
The process of taste perception can be broadly described as follows:
Even before you put food into your mouth, olfactory receptors in the nose detect smells that contribute to how the brain interprets tastes.
As you masticate (chew) food, you break it down and distribute it throughout your mouth in your saliva.
The dissolved food then enters a small opening in each taste bud, called a taste pore, which houses gustatory cells.
At the same time, the mastication sends smells into the nasopharynx (the passage that connects the mouth and nose) which further stimulates olfactory receptors.
Signals sent from both gustatory cells and olfactory receptors are interpreted by the brain as flavors.
In addition to taste buds and olfactory receptors, taste perception is influenced by a food's texture and temperature as well as chemesthesis (the detection of coolness like methol or spiciness like chili via receptors in mucus membranes of the mouth).
Anatomy and Location of Taste Buds
Taste buds on your tongue are so-named because they consist of a dense layer of bud-like organs—called papillae —on the dorsal (upper) surface of the tongue.
When you are born, you actually have more taste buds than you will in later life. Most children have around 10,000 taste buds at birth, the number of which will steadily decrease with age along with the size of the buds. By older age, the number may fall anywhere from 2,000 to 4,000.
There are different types of taste buds with different functions, including:
Fungiform papillae: These taste buds are found on the main surface of the tongue and have a mushroom-like appearance.
Folate papillae: These are situated near the ridges and grooves toward the back of the tongue and the sides of the tongue.
Circumvallate papillae: These consist of 10 to 14 large circular buds situated nearest the back of the throat.
Filiform papillae: These are the most numerous type interspersed with fungiform papillae on the surface of the tongue. They do not perceive taste but can perceive texture and touch.
Each papilla is populated with gustatory cells and other tissues that function as taste receptors. There are three types of gustatory cells, referred to as type 1, type 2, and type 3 taste receptors.
Taste buds form in utero during fetal development and remain with you for life. The cells are shed and re-form quite rapidly, usually within 10 to 12 days, although the process will slow as you start to age. This can lead to a progressive loss of taste buds as well as a loss of taste perception.
Tastes Detected by Taste Buds
Despite myths that different parts of the tongue experience different flavors, all taste buds (with the exception of filiform papillae) are able to perceive sweetness, savoriness, bitterness, sourness, and saltiness.
They do so based on the different molecules, chemicals, or ions released in masticated food and the specific types of receptors they stimulate:
Sweetness is perceived when sugar molecules stimulate type 1 taste receptors.
Savoriness is perceived when glutamic acid also stimulates type 1 taste receptors.
Bitterness is perceived when certain molecules stimulate type 2 taste receptors.
Sourness is perceived when hydrogen ions stimulate type 3 taste receptors.
Saltiness is perceived when sodium stimulates epithelial sodium channels in taste pores.
While most people notice a distinction between these categories of tastes, not everyone tastes things the same way. This is due in part to the number of papillae on the tongue.
"Supertasters" have more papillae on their tongues, which can make flavors overwhelming. As a result, supertasters tend to prefer milder foods.
"Subtasters" have fewer papillae on their tongues. They aren’t as sensitive to strong flavors and tend to prefer more pronounced flavors and spicier foods.
Conditions That Affect the Taste Buds
Taste disorders affect more than 200,000 people in the United. each year. Researchers believe that as many as 15% of adults may have problems with taste and/or smell.
Dysgeusia and Phantogeusia
Dysgeusia is the most common taste disorder. It is characterized by an altered taste perception in which foods may taste rancid, metallic, or bitter when placed in your mouth.
Many medications can cause dysgeusia as well as pregnancy, dry mouth, allergies, nutritional deficiencies, migraines, diabetes, stroke, and Parkinson's disease. Dysgeusia is not dangerous or life-threatening but can impact your quality of life.
When dysgeusia occurs even when there is nothing in your mouth, it is often referred to as "phantom taste perception" or phantogeusia.
Hypogeusia and Ageusia
Hypogeusia occurs when you experience a loss of taste, while ageusia refers to the total loss of taste. Both are commonly seen with severe cases of COVID-19 but can also occur with heavy smoking, hypothyroidism, anemia, Crohn's disease, diabetes, Sjogren's syndrome, severe tongue burns, stroke, and Parkinson's disease.
Many drugs, including chemotherapy drugs, antidepressants, bronchodilators, thyroid drugs, and diuretics can cause impaired taste perception.
Burning Mouth Syndrome
Burning mouth syndrome is characterized by a persistent burning sensation in your mouth. It can often accompany dysgeusia and has many of the same causes. Some cases of burning mouth syndrome are idiopathic, meaning that they occur for no known reason.
Burning mouth syndrome occurs in the absence of any injury to the tongue. The symptoms are often worse in the afternoon and evening and most commonly felt on the front of the tongue, roof of the mouth, or inside the lower lip.
Diagnosing and Treating Taste Bud Disorders
Taste disorders are diagnosed by an ear, nose, and throat (ENT) specialist, also known as an otorhinolaryngologist.
Along with a physical exam and a review of your medical history (including an assessment of any medications you take), your healthcare provider will perform tests to evaluate your smell and taste perception.
This may involve giving you drinks (like salt or glucose solutions) in gradually increasing concentrations to determine at which point you can detect tastes. You may also be given flavored solutions to compare or provided with "scratch-and-sniff" tests to determine if your sense of smell is impaired.
The treatment of taste disorders varies by the underlying cause. In many cases, resolving the underlying condition will resolve the taste problem as well.
Other treatment options include:
Adjusting your diet with flavors that accommodate changes in your taste
Adjusting or changing medications associated with taste disorders
Prescribing nutritional supplements if a nutritional deficiency is identified
Quitting cigarettes
Rinsing your with numbing mouthwashes containing lidocaine
Using tricyclic antidepressants, Neurontin (gabapentin), or benzodiazepines to ease symptoms of burning mouth syndrome
At-home treatment includes rinsing with salt water, sucking on ice to reduce swelling, eating a bland diet, and avoiding spicy or hot foods that irritate your tongue.
Summary
Taste buds are tiny bud-like protrusions on the tongue that are able to perceive sweetness, saltiness, bitterness, sourness, and savoriness. When combined with information from olfactory receptors in your nose, the brain can interpret these taste characteristics as flavors.
Taste disorders like ageusia, dysgeusia, hypogeusia, phantogeusia, and burning mouth syndrome can interfere with how you perceive tastes. Some of these conditions are short-lived or easily treated (such as taste changes caused by medications) while others may be long-lasting and harder to treat.
Taste disorders are treated by ENT specialists, also known as otorhinolaryngologists.
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