If you don't enjoy your favorite foods as much as you used to, it may be time to see your doctor. Strange as it seems, your problem may lie in your nose or mouth. Seemingly flavorless food can result from either a diminished sensation of smell or taste, but usually not both. In fact, the loss of smell is actually more common than loss of taste. Studies have found that even when food seems to become less flavorful, the ability to sense the basic four tastessalty, sweet, sour, and bitteroften remains intact.
Smell and taste disorders are very common in the general population. One study suggests that more than two million Americans have smell and taste disorders, while another estimate suggests that more than 200,000 people seek help from their physicians for the problem.
As people age, they experience a decreased ability to smell and to taste. According to Susan Schiffman, PhD, of Duke University Medical Center, people begin to experience diminished sensations of taste and smell around the age of 60, and this trend worsens and becomes more pronounced by the time people reach their 70s. Certain medical conditions, medications, and a lack of certain nutrients can all contribute to decreased senses of smell and taste.
Tasty Team Work Smell and taste work as a team to allow for the sensation of flavors. With one sensation diminished, the flavor experience can be entirely different. Think of freshly baked chocolate chip cookies, for example. Nerves in the nose sense the airborne molecules released from the odor-causing agents in the cookies. After the molecules drift up to the nose or are drawn up through breathing or sniffing, the detected odor is sent to the smell area of the brain. The average adult has 10,000 taste buds coating the tongue's surface, all of which are responsible for the sensation of taste. Taste buds on the tip of the tongue detect sweetness; bitterness is detected by the back taste buds, while the side taste buds detect salt and sour tastes. Once you put the chocolate chip cookie in your mouth, these taste receptors send nerve impulses to the taste center of the brain. The brain then uses both the taste and smell sensations to distinguish the flavors that you recognize as being characteristic of freshly baked cookies. Medical Conditions But what if you had a condition that interfered with your sense of either taste or smell? Simple tastes such as the basic salty, sweet, sour, and bitter can be detected without smell, but the more complicated flavorslike the rich, velvety sensation of a mixture of chocolate chips, walnuts, butter, and brown sugarrequire the sensations of both smell and taste to be fully appreciated.
Some common medical conditions, such as sinus infections, nasal polyps, upper respiratory infections, and allergies can trigger a loss of smell with subsequent alteration in taste perception. In this case, your taste and smell center would have to rely solely on your taste buds to recognize any cookie flavor at all. Maria Zipp, MD, a Chicago-area internist, knows first hand what it's like to be unable to taste food, a sensation she describes as "very disconcerting." After seeking treatment for her taste disorder at Loyola University Medical Center in Maywood, IL, she was placed on high-dose antibiotics to clear up what was diagnosed as a subacute sinus infection. Shortly after her course of antibiotics, her normal taste sensations returned. Less common medical problems likely to affect smell include head trauma, Alzheimer's disease, Parkinson's disease, and multiple sclerosis. Even certain dental conditions can affect taste perception. Gingivitis, tooth infections, and periodontal disease can leave enough of an unpleasant taste in your mouth to disrupt normal taste perception. Newly or poorly fitted dentures can also change taste perception because they cover taste buds located on the roof of the mouth. Medications People's use of prescription medications typically increases as they age. Many commonly prescribed medications have the potential to alter taste perception due either to their own bad taste or the potential to cause a dry mouth.
In up to 5% of people, antibiotics, such as Biaxin, can leave a bitter metallic taste in the mouth, although normal taste perception generally returns after discontinuing the medication. Capoten, used to treat high blood pressure, may cause the mouth to be sore and dry, and some people develop a loss of taste perception. Certain protease inhibitors, which are used to treat HIV infection, have also been shown to modify taste perception. These protease inhibitors are predominantly bitter tasting, but patients also report an astringent, metallic, sour, and burning taste. Antidepressants such as amitriptyline HCL (Elavil), used by half a million people, have a bitter and unpleasant taste. In one study, the drug also seemed to have the potential to actually block responses to other taste stimuli. But not all medications rob you of your ability to smell and taste. Researchers have noted that some medications, such as allergy medications, can actually improve smell and taste perception. If medications are causing dry mouth, your doctor may be able to prescribe a different one. In order to help manage dry mouth, artificial "saliva" is available via prescription, and drinking plenty of water is also encouraged for dry mouth disorders.
Diet/Nutrients A deficiency of certain nutrients, such as zinc , can foster altered taste perception. Foods that contain significant amounts of zinc include meat, fish, poultry, milk, whole grains, nuts, and lentils. Zinc supplementation appears to be effective in treating taste disorders only when serum zinc concentrations are low. Indiscriminate zinc supplementation will not improve a taste disorder if it is a result of another medical condition or prescription use. One study, however, has noted that the administration of zinc can prevent or correct taste disorders resulting directly from external radiation to the head and neck region. In this study, a small group of cancer patients received supplemental zinc sulfate three times per day while undergoing radiation. Those on supplemental zinc experienced less alteration in taste perception and had a faster recovery of normal taste acuity after the radiation treatment. Although deficiencies of other nutrients, such as vitamins A , B6 , and B12 , have been implicated as triggering taste alteration, there have been few published studies to actually confirm or refute this connection. However, researchers know that vitamin A and some of the B complex vitamins contribute to a healthy mouth. A deficiency of vitamin A can cause texture changes in the tongue, particularly the taste buds. Deficiencies of some B vitamins can lead to a condition called glossitis, which causes the tongue to become swollen and red with some sensation of pain or burning upon eating.
Flavoring "Tasteless" Food There are some simple techniques you can do in your own kitchen to help enhance the flavor of foods. Because the ability to sense sweet and salty tastes may diminish sooner than the ability to taste bitter and sour, Debbie Lofley, a registered dietitian and director of nutrition services for the Marriott Corporation, suggests using packaged herb blends such as Mrs. Dash and Parsley Patch. These blends fulfill the taste sensation of salt while providing less sodium than you would get from the salt shaker. While few, if any, treatments exist to restore taste and smell, Schiffman has been able to block the bitterness of some drugs by adding sweeteners, sodium chloride (table salt), and polydextrose (a food thickener). She has also found that adding flavored powders like beef, bacon, and cheese to a variety of foods can significantly increase the flavor and enjoyment of foods among people with impaired taste sensation. The American Dietetic Association offers some more tips on increasing the flavor of your foods: Perk up flavors by using herbs, spices, and lemon juice.Texture adds to the flavor of food, so add some crunch to meals. Try crushed crackers, chopped nuts, or toppings made with uncooked oat cereal.Avoid foods that are very hot or very cold. Extreme temperatures tend to decrease the flavors of foods.If you smoke, stop. Smoking reduces the ability to perceive flavors.Avoid exposing your taste buds to strong or bitter flavors, such as coffee, which can temporarily deaden sensitivity to other flavors.
RESOURCES: International Food Information Center http://www.ific.org/ Smell and TasteNational Institute on Deafness and Other Communication Disorders http://www.nidcd.nih.gov/ References Bromley S. Smell and taste disorders: A primary care approach. American Family Physician. 2000;61:427-36. Available at: http://www.aafp.org/afp/20000115/427.html. Netter F. Nervous system: Anatomy and physiology. In: The Ciba Collection of Medical Illustrations. Vol 1. CIBA Pharmaceutical Company; 1986. Last reviewed December 2006 by Lawrence Frisch, MD, MPH Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.