Smell and Taste
Disorders in Elders
There
are certain things in this world that we ignore most especially when it comes
to Men’s health. Men usually loves to
eat what ever they want, we cannot barely imagine what kind of appetite do they
have , sometimes they eat a lot though they feel that they were full. But who
would resist the savory taste of adobo
(Philippines favorite). The spice and hotness of Bicol express (a special dish originated in Bicol region, Philippines).
The delicate taste of Kare-Kare. The
mouth watering aroma of the hot pandisal
at Graceland Bakers Plaza. Just a few words about the smell and taste of food can evoke pleasant images and
stimulate appetites. But where does that leave people who have a disease or
disorder, or are on a medication that interferes with these two vital senses?
What about those who find that the physiological changes of aging leave that
sweet apple pie tasting flat or even sour? They start pushing food away, losing
weight, and putting themselves in jeopardy for further problems.
Olfactory
(smell) and gustatory (taste) impairment can be caused by normal physiological
changes associated with aging, but many chronic or acute disorders and some
medications can be the culprits. People tend to add extra salt and sugar to
counteract the tastelessness they perceive in their food, which can pose a
particular health risk for those with chronic diseases, such as hypertension
and diabetes.1 Likewise, when it becomes critical for people to
follow a therapeutic diet, such as a low-sodium diet, loss of smell and taste
can quickly lead to non-compliance. Smell and taste are protective to all of us
by detecting toxins, polluted air, gas leaks, smoke, and spoiled food. Losing
these senses jeopardizes our basic safety. A sudden loss of smell can even provoke
depression in some people. Sometimes these deficits raise a warning flag
for more serious underlying conditions, such as brain lesions and tumors.
An array
of medical terms identifies the different types and degrees of olfactory and
gustatory impairment. Anosmia is the complete loss of smell, while hyposmia
describes a partial but diminished sensitivity or acuity of smell. Similarly, ageusia
is a complete absence of taste, while hypogeusia is a diminished
sensitivity or acuity of taste.
Olfactory
and gustatory impairment can affect all ages, but it’s most common in elderly
persons. Typically, sense of smell and taste starts to diminish after about age
50 and worsens progressively with time.
An
estimated 50% of adults 60 or older are affected by some loss of smell; while
taste is less affected, it also diminishes with age. Almost half of
elders who experience a smell or taste disorder report a resulting decrease in
appetite. As the elderly population continues to expand rapidly,
these problems are expected to create a growing health challenge.
From Taste Buds to Nasal Receptors
The tongue’s taste buds recognize four basic properties — salty,
bitter, sweet, and sour — independent of the sense of smell. In contrast,
olfactory sensors in the nose can detect a much larger variety of aromas and
odors. Together, tastes and aromas produce flavors; for a person to recognize
most food flavors, smell and taste must work together. Approximately two-thirds
of taste acuity depends on smell.
Taste and smell are chemosensory in nature, or known as the
chemical senses, because they detect the chemicals or molecules from which
aromas or flavors originate. For example, when your host greets you at the
door, you know in an instant that a lamb roast is cooking in the oven and an
apple pie is cooling on the kitchen counter. You can name the menu before you
see it as millions of airborne molecules, or odorants, fill the air. Mucus
traps these molecules when you inhale them and dissolves and distributes them
to the appropriate olfactory sensors or receptors. These sensors are clustered
in the olfactory epithelium located at the top of the nasal cavity. A moist
nasal cavity aids in the stimulation of the olfactory neurons in the receptors.
The neurons produce the electrical impulses that are carried along the
olfactory nerve to the brain, where they are interpreted as odor or aroma.
Taste buds are onion-shaped structures of 50 to 100 taste cells,
also known as gustatory cells. Each has fingerlike projections called
microvilli that poke through an opening or pore at the top of the taste bud.
The tongue contains most of the taste buds, although some are also scattered
over the soft palate, pharynx, and larynx. Chemicals from food dissolve in
saliva and contact the taste cell through the taste pore, where they
communicate with certain proteins on the surfaces called taste receptors. These
interactions trigger signals to the brain along three cranial nerves: the
facial (VII), glossopharyngeal (IX), and vagus (X), depending on where the
taste impulses arise.
The Roots of Smell and Taste Problems
Many factors can cause alterations or disturbances in olfactory
and gustatory pathways that lead to impairment. These include physiological
changes associated with aging, systemic diseases, oral disorders, some
medications, malnutrition, and environmental agents.
Aging: Physiological changes associated with aging are a potential
cause of reduced taste and smell sensitivity in elders. The numbers of taste
cells and sensory receptors decline as people age. Taste buds detecting salty
and sweet properties are most affected. Saliva production, which helps to
dissolve chemicals in food or drink and transport them to the taste buds,
diminishes in elders, causing mouth dryness. Similarly, elders experience a
gradual atrophy of their olfactory system.
Diseases and disorders: Several medical conditions can
further degrade the acuity of smell and taste in elders. For example,
gingivitis and periodontitis release bad-tasting materials in the mouth that
interfere with external smells. Tumors or lesions in the oral cavity or brain can
damage the gustatory pathways, nerves, or relevant parts of the brain. Allergic
rhinitis, sinusitis, or polyps can cause swelling of the nasal mucosa or create
obstructions, preventing air from reaching the olfactory area.
Some upper respiratory infections, such as influenza, can
destroy nasal receptors, often causing permanent anosmia. Systemic diseases,
such as diabetes mellitus, hypothyroidism, Alzheimer’s disease, and Parkinson’s
disease, can affect smell and/or taste in some cases because of olfactory or
gustatory neural damage.
Medications and other causes: Medications are an important and
frequently overlooked cause of olfactory and gustatory impairment, often an
issue for elders who may take several. Numerous drugs are known to alter smell
and taste by acting on peripheral receptors, the chemosensory neural pathway,
and/or the brain. For example, antidepressants, antihistamines, and
anticholinergics cause mouth dryness, thereby reducing taste acuity. Local
decongestants, such as naphazoline, paralyze nasal cilia.
Selected Medications That Can Cause Taste/Smell Dysfunction
- AIDS and HIV drugs: didanosine (Videx), zalcitabine (Hivid), zidovudine (Retrovir)
- Anti-inflammatory drugs: colchicine, dexamethasone (Decadron), gold (Myochrysine), hydrocortisone (Aeroseb-HC, Hydrocort)
- Anti-ulcer, anti-GERD: omeprazole (Prilosec)
- Anticonvulsants: phenytoin (Dilantin), carbamezapine (Tegretol)
- Antidepressants: amitriptyline (Elavil), imipramine (Tofranil), desipramine (Nopramin), doxepin (Sinequan)
- Antihistamines and decongestants: chlorpheniramine (Chlo-Amine), pseudoephedrine (Sudafed)
- Antihypertensive and cardiac medications: captopril (Capoten), clonidine, diltiazem (Cardizem), enalapril (Vasotec), nifedipine (Procardia), nitroglycerin, propranolol (Inderal), furosemide (Lasix)
- Antimicrobial agents: ciprofloxacin (Cipro), tetracycline, clarithromycin (Biaxin), sulfasalazine, metronidazole (Flagyl)
- Antineoplastics: cisplatin (Platinol), vincristine (Oncovin)
- Antiparkinsonian drugs: levodopa (Larodopa; with carbidopa: Sinemet)
- Bronchodilators: albuterol sulfate (Proventil, Ventolin), cromolyn sodium
- Hyper- and hypoglycemic drugs: glipizide, diazoxide, phenformin and derivatives
- Hypnotics and sedatives: flurazepam (Dalmane), quazepam (Doral)
- Lipid-lowering agents: lovastatin (Mevacor)
- Muscle relaxants: baclofen (Lioresal), dantrolene sodium (Dantrium)
- Other: allopurinol, calcitonin, iron, nicotine, potassium iodide, vitamin D/Calcitriol
- Thyroid drugs: methimazole (Tapazole)
Cigarettes, alcohol, illicit drugs,
hot liquids, or other environmental factors may also injure taste buds. On
the palate, dentures may cover taste buds. In addition, head or nose trauma can damage
the olfactory bulbs, nerves, or brain lobes. Radiation therapy of the head and
neck can cause mouth dryness and directly damage taste receptors. Malnutrition
in the elderly could also further diminish the chemosensory perception.
Reference:
When the Nose No Longer Knows
Smell and Taste Disorders in Elders
By: Wiera Malozemoff, RN, MS, CS and Devin Sue Barriault, RN,
MSN, CMSRN and Colleen Manning Osten, RD
