You may have noticed that as you age, your sense of taste begins to change. No, I'm not talking about the growing appeal of comfortable shoes or really stretchy sweat pants, but the sensory structures inside your mouth. Maybe that chili recipe needs more cayenne than it used to, or green vegetables just don't taste right. What's happening?
How We Taste:
First, a bit of taste physiology: the raised bumps, or taste papillae, you see when you stick out your tongue in the mirror are made up of specialized epithelial cells. Arranged around and inside these are your taste buds, only visible with the help of a microscope. The average person has about 4,600 taste buds on their tongue. In addition, taste buds can be found on the roof of the mouth, in the esophagus, and at the back of the throat. They respond to five basic taste stimuli: sweet, salty, sour, bitter and the more recently recognized "umami," the savory flavors of certain amino acids.
Our ancestors had their taste receptors to thank for helping them avoid poisonous or decaying food, as these trigger bitter or other unpleasant tastes.
When you take a bite, your saliva helps dissolve the food, allowing tiny hairs or microvilli within the taste buds to capture the food molecules. These, in turn, trigger nerves to carry the sensation to the brain, where the flavor is perceived.
Taste receptors are heroes in the world of cell turnover, regenerating about every ten days. With age, though, it's believed that taste buds simply aren't reproduced at the same rate: fewer taste buds, diminished flavor perception. Cell membranes, the machinery that transmits electrical signals, also change with time and become less effective.
Some older people hang on to their sense of taste with little decline. Others, especially those suffering from dry mouth or who are taking certain medications (as many as 250 have been implicated), like antihistamines or antidepressants, may lose much of their taste perception. Certain conditions, like stroke, Bell's palsy, Parkinson's, diabetes and depression, can also cause a loss or altering of taste. Even tooth extractions can do damage to the nerves that transmit taste sensation to the brain.
How We Smell:
How well we smell also plays a large role in what we taste. It is probably a dwindling sense of smell, or anosmia that accounts for most changes in taste with age.
Sensory cells within the nose transmit olfactory messages to the brain. Over time, these smell receptors, like those for taste, stop regenerating as rapidly. They're also more vulnerable to damage by environmental contaminants like air pollution, smoking and microbes. Diseases like stroke, epilepsy and various medications can also affect how smell is perceived by the brain.
One large-scale study in Wisconsin found that almost two-thirds of subjects between 80 and 97 years of age had some form of olfactory, or smell impairment. The researchers concluded that as many as 14 million older adults in the United States have a diminished sense of smell.
At the minor end, a loss of taste perception can make a dinner out less enjoyable. But for the elderly, malnutrition is a real danger, either from eating less or making less nutritious choices.
People whose sensitivity to salt drops may add too much salt to their food, a potential risk if they have high blood pressure. A reduced sensitivity to sweetness is a danger for diabetics if they add extra sugar to compensate. In addition, an altered sense of taste can make old favorites, like fruits and vegetables, less appealing. This has been shown to erode immunity to disease, even when the calories consumed remain the same.
Age-related loss in flavor perception is likely not reversible. However, some causes -- such as polyps or other masses obstructing the sinuses, infection, or inflammation -- might be temporary, so you may want to consider visiting an ear, nose and throat (ENT) specialist for further investigation. In the meantime, here are some things you can do if you or someone you're caring for is struggling with things not tasting right:
- Enhance the flavor
Spices can boost the flavor of a food but many elderly people cannot tolerate them. If spices don't bother your gastrointestinal system, enjoy! Avoid salt, especially if you suffer from high blood pressure. Simulated flavors, like bacon or cheese, can be added to soups and vegetables to make them more palatable. Monosodium glutamate has been found to improve appetite among the elderly. Try acidic flavors like lemon to boost the flow of saliva.
- Enhance the aroma
Season chicken, beef and fish using low-sodium marinades; for example, chicken can be marinated in chicken flavor to intensify its aroma.
- Add variety
Avoid sensory fatigue by having a variety of foods and textures on your plate. Then try switching from item to item between bites to keep your taste buds firing.
- Play with temperature
Food that's too hot or too cold may not be tasted as thoroughly; try varying the temperature to maximize its flavor.
There are many factors beyond pure taste that affect how much we enjoy our food. Experiment with presentation and even bite size to maximize your eating enjoyment.
Cecile L. Phan, Jodi L. Kashmere, Sanjay Kalra. "Unilateral Atrophy of Fungiform Papillae Associated with Lingual Nerve Injury". The Canadian Journal of Neurological Sciences, Volume 33, Number 4 / November 2006.
Claire Murphy, PhD; Carla R. Schubert, MS; Karen J. Cruickshanks, PhD; Barbara E. K. Klein, MD, MPH; Ronald Klein, MD, MPH; David M. Nondahl, MS." Prevalence of Olfactory Impairment in Older Adults." JAMA. 2002;288(18):2307-2312. doi: 10.1001/jama.288.18.2307. http://jama.ama-assn.org/content/288/18/2307.full
Cowart, B. J. Relationships between Taste and Smell across the Adult Life Span. Annals of the New York Academy of Sciences, 561: 39-55. doi: 10.1111/j.1749-6632.1989.tb20968.x (personal communication with author)
Schiffman, S. "Taste and Smell Losses in Normal Aging and Disease." JAMA. 1997;278(16):1357-1362. doi: 10.1001/jama.1997.03550160077042