When the Nose No Longer Knows

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

www.nurse.com