Health Information

Taste and Smell Disorders

IMAGE Imagine not being able to smell your favorite aromas, whatever they may be (perhaps cinnamon rolls, freshly brewed coffee, gardenias, or balsam). Think about the foods you like so much. What if you couldn’t taste them? This is a daily reality for people who partially or completely lose their senses of taste and smell.

Some of life’s most pleasurable experiences are associated with the senses of taste and smell. For that reason, disorders that cause a loss of taste and smell can be particularly frustrating. They can also be dangerous when they impair a person’s ability to notice smoke, harmful chemicals and poisonous fumes, or food that has gone bad. Because taste and smell disorders can decrease a person’s enjoyment in eating, they may also lead to weight loss and even malnutrition.

The Taste-Smell Link

Remember when you were a child and your mother made you eat something that you didn’t like? You might have held your nose as you swallowed. Even then, you sensed that there was a connection between taste and smell. And you were right: taste and smell are closely linked. Taste buds on your tongue identify taste and nerves in your nose identify smells. Both sensations combine to play a role in your ability to recognize and appreciate flavors.

Five basic taste sensations can be recognized without the sense of smell. They are:

  • Sweet
  • Sour
  • Bitter
  • Salty
  • Umami (the taste elicited by glutamate, found in protein-rich foods such as chicken broth, meats, extracts, and some cheeses)

However, to recognize many other, more complex flavors, your sense of smell is necessary. For example, if you held your nose while eating some lemon pudding, you would have difficulty identifying the lemon flavor because it is sensed mostly by odor. You would, however, be able to distinguish its sweetness or bitterness.

If you’re having difficulty tasting your food, you may have a problem with your taste buds, but it’s more likely that the problem is with your sense of smell.

What Are Taste and Smell Disorders?

People with taste disorders may complain of phantom taste perceptions (tasting something that isn’t there); a reduced ability to taste sweet, sour, bitter, salty, and umami; or distorted taste. Although some people can detect no taste, true loss of taste is rare. Perceived loss of taste is usually related to loss of smell.

People with smell disorders experience either a loss in their ability to smell or changes in their sense of smell. Some develop hyposmia, a decreased ability to detect odors. Others can’t detect odors at all, which is called anosmia. Some people notice that familiar odors have become distorted. For example, an odor that usually smells pleasant may smell foul to them or they may perceive an odor that isn’t present.

Causes of Taste and Smell Disorders

A small number of people are born with taste disorders. Most taste and smell disorders can be caused by:

  • Upper respiratory infections (colds and flu)
  • Breathing allergies
  • Nasal congestion from irritants, such as pollutants and cigarette smoke
  • Sinus infections
  • Nasal polyps (noncancerous growths in the nose and sinuses)
  • Head injuries
  • Bells Palsy (infection of the facial nerves)
  • Exposure to certain chemicals, such as insecticides and solvents
  • Certain medicines, such as antibiotics and blood pressure pills
  • Radiation treatments for head and neck cancers
  • Advancing age, which can make sense of smell less accurate
  • A number of other health problems, including:
  • Oral health problems, such as gum disease
  • Some surgeries, such as third molar extraction and middle ear surgery
  • Smoking and cocaine use

Diagnosis and Treatment of Taste and Smell Disorders

Smell disorders may be diagnosed with “scratch and sniff” tests that assess accuracy in identifying different easily recognizable odors (such as coffee and chocolate) and loss of smell. A nasal examination may be performed with an endoscope (a camera that can look inside the nose). X-rays (usually CT scans) may be needed to look at the sinuses and nerves in the nose.

Taste disorders may be diagnosed through tests that measure the lowest concentration of a chemical that a person can detect or identify, taste comparison tests, and tests that measure taste intensity.

Some taste and smell disorders can be treated, but others cannot. Depending on the cause, treatment may include treating an underlying medical condition, changing or adjusting medicines, or surgery to remove obstructions in the nose, such as polyps. In many cases, people experience a spontaneous recovery when an illness or allergy that is causing the disorder resolves.

If You Have Lost Taste or Smell

If you have lost taste or smell, you should see your doctor. It may resolve in time, if the underlying problem is temporary or treatable. Quitting smoking may help improve your senses of taste and smell. If the loss is permanent, adjustments can be made to enhance your enjoyment of eating, such as eating warm food, flavor-enhanced foods, or stronger flavored foods. But be careful not to add too much salt or sugar. Instead, you can intensify flavor with herbs and make food more visually and texturally appealing.

  • Asthma and Allergy Foundation of America

    http://www.aafa.org

  • Taste and Smell Clinic at the University of Connecticut Health Center

    http://uconntasteandsmell.uchc.edu/

  • Canadian Society of Otolaryngology

    http://www.entcanada.org/

  • Health Canada

    http://www.hc-sc.gc.ca

  • Bromely S. Smell and taste disorders: a primary care approach. Am Fam Physician. 2000 Jan 15;61(2):427-436. American Academy of Family Physicians website. Available at: http://www.aafp.org/afp/2000/0115/p427.html.

  • Smell & taste. American Academy of Otolaryngology–Head and Neck Surgery website. Available at: http://www.entnet.org/HealthInformation/smellTaste.cfm.

  • Disorders of smell and taste. American Rhinologic Society website. Available at: http://care.american-rhinologic.org/disorders%5Fof%5Fsmell%5Ftaste. Accessed July 29, 2012.

  • Taste and smell disorders. National Institutes of Health website. Available at: http://health.nih.gov/topic/TasteandSmellDisorders. Accessed July 29, 2012.