The myth of tongue and taste

If you had to describe chocolate to someone who had never tasted it before, what would you say? How about vanilla? Or strawberry? It wouldn't be easy. And even if you did a good job of describing these flavors, it's hard to imagine anyone truly understanding their taste without actually tasting them.

In fact, taste is a sense that is hard to describe and easy to take for granted. It has a lower profile than the other senses, but that may underestimate how much it adds to a person's quality of life. Just ask anyone who has lost their sense of taste, even temporarily.

The myth of tongue and taste

Taste buds aren't only on your tongue. They can be found elsewhere, including the soft palate (at the back of the roof of the mouth) and throat.

When taste buds come into contact with foods or drinks, specialized cells send signals to the brain that identify the type of taste:

• sweet
• sour
• salty
• bitter
• savory (also called umami).

While most of these are self-explanatory, savory deserves some explanation. Savory foods are described as flavorful, meaty, or "brothy," but distinct from the other tastes. Examples of savory foods include:

• chicken broth
• shiitake mushrooms
• certain fish sauces.

It has long been said that the tongue has a "taste map." Taste buds for sweet foods are on the tip of the tongue, taste buds for salt are along the sides, and those for sour and bitter foods are toward the back. That's a myth! Taste buds that identify each of the five tastes are found all over the tongue, though there are more taste buds along the sides than in the center. And there's a particularly high concentration of taste buds sensitive to bitterness at the back of the tongue, presumably to warn us before we swallow something that might be dangerous.

In 2006, researchers made a breakthrough discovery regarding the detection of sour taste. They identified the protein that allows the tongue to identify a food as sour. This seems to be another "alarm system" to flag foods that might best be avoided.

When taste goes wrong

Some of the more common causes of taste problems include:

• Problems with sense of smell. Smell and taste are closely linked. Problems with your ability to smell can alter the taste of foods. Nasal congestion is a common cause of taste trouble. Allergies, sinus infections, or even exposure to secondhand smoke are common culprits. Infection with SARS-CoV-2, the virus responsible for the COVID-19 pandemic, caused a dramatic rise in the number of people experiencing problems with the ability to smell or taste normally. In most cases, these problems are temporary.
• Medication side effects. There are hundreds of medicines that can alter taste sensation. They may affect the cells in the taste buds, impair nerve signals between the tongue and the brain, or alter saliva.
• Dry mouth. Saliva is essential for oral health. And that includes being able to taste normally. Reduced saliva can cause dry mouth and altered taste.
• Acid reflux. Gastroesophageal reflux disease (GERD) is a digestive disorder that causes heartburn. It develops when acid flows back (refluxes) from the stomach into the esophagus (the tube that carries food from your mouth to your stomach).
• Dental problems. Examples include a tooth abscess or gum infection.
• Smoking. Smokers have a diminished sense of taste compared to nonsmokers. Fortunately, it's reversible when you quit.
• Chronic medical conditions. Diabetes, kidney or liver disease, and brain disorders (including Alzheimer's disease and Parkinson's disease) can impair your ability to taste and smell.
• Aging. Your sense of taste may decline after age 50 because taste buds start to decline in number and sensitivity, and because the sense of smell (which affects taste) also declines.

The bottom line

Most people would agree that ice cream or apple pie tastes good. We may not agree on just how good they taste or how to describe their taste. But a big part of what you consider delicious is related to the culture you grew up in and the foods you were exposed to. Even among people in the same culture or same family, it's probably true that no two people experience taste in exactly the same way.

People who have lost their sense of taste usually miss it terribly. So, don't take it for granted - and don't take any chances. If you notice a persistent change in your sense of taste, it's important to get it checked out. There may be a perfectly innocent explanation - a new medication or nasal congestion from allergies, for example. But it could also be something more important.