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Nutrition and sensory loss
Nutrition and Well-Being
Nutrition and Sensory Loss Peggy K. Yen, RD, MPH
P
oor appetite and weight loss are significant problems for elders in many settings. A contributing factor frequently cited is the change in taste and smell (gustatory and olfactory) sensation that occurs with aging. Flavor perception is a combination of smell and taste, along with the particular tactile qualities of each food, such as the way it feels in the mouth. Pinching your nose closed while eating a favorite meal can give you an appreciation of the difference smell makes in the taste of food and stimulation of appetite. In general, women seem to retain smell and taste perception better than men. Sensory decline takes place gradually beginning around age 60, more noticeably around 70. In one review, half to three-quarters of people 65 and older had major olfactory impairment, with those over 80 showing the most compromised sensory capability.1 Elders may not even realize that their gustatory and olfactory senses are compromised. The nutrition question raised by sensory loss is whether or not it compromises dietary intake and nutritional status. H O W TA S T E A N D S M E L L A R E AFFECTED BY AGE When tested for smell and taste threshold, elderly people show measurable effects on sensitivity. Elderly women had only about 10% of the smell function and 50% of the acuity for sweet taste as younger women similarly tested. Acuity for salty taste was much better at 72%. Age was a factor in another study when young, middle aged, and elderly people were tested using a salt and water solution: the older the test subject, the less likely they were to detect the salt. When the salt was mixed with tomato soup, the results for young and old subjects were more similar, although the older subjects still detected saltiness only at higher concentrations. In testing studies, taste sensitivity varies among individual subjects, a reminder that physiologic aging takes place at different rates in different people. Information on the prevalence of smell/taste problems from the Disability Supplement to the National Health Interview Survey shows that 2.7 million (1.4%) U.S. adults have an olfactory problem and 1.1 million 118
(0.6%) adults report a gustatory problem.2 In this nationally representative sample, about 40% of those with a chemosensory problem (taste or smell) were at least 65 years old. Overall health status, functional limitations, depression, and other health-related characteristics were associated with an increased rate of smell and taste disorders. Changes in taste and smell perception caused by the aging process are difficult to separate from those caused by smoking, medication use, radiation therapy, nasal disorders, and neurologic conditions like Alzheimer disease. Smoking, for example, causes a reversible decrease in the ability to smell in people of all ages. Radiation to the head and neck damages taste buds, commonly causing taste disorders, including enhanced bitter taste. Some medicines leave a bitter flavor, affect saliva production, or cause nausea, altering taste and appetite. Medications causing taste changes include hypoglycemics (phenformin and glipizide), antiparkinsonian drugs (levodopa), anticoagulants (phenindione), antihistamines (chlorpheniramine), psychoactive drugs (lithium, trifluroperazine) and salicylates. Health conditions such as diabetes and liver disease also may alter taste and smell. D O E S S E N S O RY D E F I C I T A F F E C T F O O D I N TA K E ? Women with a low smell threshold have been shown to have lower intakes of fat and calories. Women with lower taste and smell acuity, in the same study, were more likely to report a decline in appetite. Dietary responses to taste and smell disorders varied widely in a study of more than 300 young and old people.3 Changes in weight (gain and loss) were seen in the group with sensory deficits and the group without. Decreased odor perception has been related to lower calorie and iron intake. When elderly people were allowed to choose unlimited sweet breakfast foods, the concentration of sugar in the food had no effect on the amount eaten, even though their sensitivity to sweet taste was compromised. It seems logical that taste and smell changes affect appetite. Whether people adapt over time to this change or Geriatric Nursing
Volume 25
Number 2
whether sensory changes lead inevitably to compromised nutritional status is unclear. Research doesn’t show a causal relationship between decreased taste and smell acuity and malnutrition. Elders continue to report decreased appetite and taste changes as a reason for not eating, especially in long-term care institutions, and caregivers help provide them with good nutrition care. CAREGIVERS CAN HELP Elderly people sometimes report that food tastes unpleasant or bitter. This reaction may be an oral condition that can be helped by brushing the tongue and rinsing the mouth. Oral conditions affecting composition and amount of saliva also can affect flavor perception. Modification of individual foods adds appeal, “mouth feel,” and extra flavor to compensate for loss of taste and smell. Herbs, spices, and flavoring can be added to food during cooking or directly at the table. A little hot sauce on eggs or lemon juice on vegetables perks up the flavor. Adding texture to food with nuts, fruit bits like raisins, crushed cereal, or crackers and leaving larger pieces in mashed food adds what is called “mouth feel” that enhances its appeal even though it doesn’t add flavor. Serving cold foods cool but not ice cold enhances flavor, as does serving foods at a range of temperatures for variety. Making food colorful adds interest and makes it more attractive to eat. That’s the idea behind parsley garnishes and pools of sauce with squiggly designs that are so popular in restaurants. Chewing food well brings out maximum flavor and aids digestion. Smoking and regular consumption of strongly flavored things, like coffee, reduces the ability to perceive flavors, so elders can be encouraged to modify these habits. REFERENCES 1. Doty RL, Shaman P, Applebaum SL, et al. Smell identification ability: changes with age. Science 1984;226:1441-3. 2. Hoffman HJ, Ishii EK, Macturk RH. Age-related changes in the prevalence of smell/taste problems among the United States adult population. Results of the 1994 Disability supplement to the National Health Interview Survey (NHIS). Ann N Y Acad Sci 1998;855:716-22. 3. Mattes RD, Cowart BJ. Dietary assessment of patients with chemosensory disorders. J Am Diet Assoc 1994;94:50-6.
PEGGY K.YEN, RD, MPH, is a nutrition consultant in the cardiovascular health and nutrition division of the Family Health Administration in the Maryland Department of Health and Mental Hygiene in Baltimore. 0197-4572/$ - see front matter © 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.gerinurse.2003.12.011
March/April 2004
119
Nutrition and Sensory Loss Peggy K. Yen, RD, MPH
P
oor appetite and weight loss are significant problems for elders in many settings. A contributing factor frequently cited is the change in taste and smell (gustatory and olfactory) sensation that occurs with aging. Flavor perception is a combination of smell and taste, along with the particular tactile qualities of each food, such as the way it feels in the mouth. Pinching your nose closed while eating a favorite meal can give you an appreciation of the difference smell makes in the taste of food and stimulation of appetite. In general, women seem to retain smell and taste perception better than men. Sensory decline takes place gradually beginning around age 60, more noticeably around 70. In one review, half to three-quarters of people 65 and older had major olfactory impairment, with those over 80 showing the most compromised sensory capability.1 Elders may not even realize that their gustatory and olfactory senses are compromised. The nutrition question raised by sensory loss is whether or not it compromises dietary intake and nutritional status. H O W TA S T E A N D S M E L L A R E AFFECTED BY AGE When tested for smell and taste threshold, elderly people show measurable effects on sensitivity. Elderly women had only about 10% of the smell function and 50% of the acuity for sweet taste as younger women similarly tested. Acuity for salty taste was much better at 72%. Age was a factor in another study when young, middle aged, and elderly people were tested using a salt and water solution: the older the test subject, the less likely they were to detect the salt. When the salt was mixed with tomato soup, the results for young and old subjects were more similar, although the older subjects still detected saltiness only at higher concentrations. In testing studies, taste sensitivity varies among individual subjects, a reminder that physiologic aging takes place at different rates in different people. Information on the prevalence of smell/taste problems from the Disability Supplement to the National Health Interview Survey shows that 2.7 million (1.4%) U.S. adults have an olfactory problem and 1.1 million 118
(0.6%) adults report a gustatory problem.2 In this nationally representative sample, about 40% of those with a chemosensory problem (taste or smell) were at least 65 years old. Overall health status, functional limitations, depression, and other health-related characteristics were associated with an increased rate of smell and taste disorders. Changes in taste and smell perception caused by the aging process are difficult to separate from those caused by smoking, medication use, radiation therapy, nasal disorders, and neurologic conditions like Alzheimer disease. Smoking, for example, causes a reversible decrease in the ability to smell in people of all ages. Radiation to the head and neck damages taste buds, commonly causing taste disorders, including enhanced bitter taste. Some medicines leave a bitter flavor, affect saliva production, or cause nausea, altering taste and appetite. Medications causing taste changes include hypoglycemics (phenformin and glipizide), antiparkinsonian drugs (levodopa), anticoagulants (phenindione), antihistamines (chlorpheniramine), psychoactive drugs (lithium, trifluroperazine) and salicylates. Health conditions such as diabetes and liver disease also may alter taste and smell. D O E S S E N S O RY D E F I C I T A F F E C T F O O D I N TA K E ? Women with a low smell threshold have been shown to have lower intakes of fat and calories. Women with lower taste and smell acuity, in the same study, were more likely to report a decline in appetite. Dietary responses to taste and smell disorders varied widely in a study of more than 300 young and old people.3 Changes in weight (gain and loss) were seen in the group with sensory deficits and the group without. Decreased odor perception has been related to lower calorie and iron intake. When elderly people were allowed to choose unlimited sweet breakfast foods, the concentration of sugar in the food had no effect on the amount eaten, even though their sensitivity to sweet taste was compromised. It seems logical that taste and smell changes affect appetite. Whether people adapt over time to this change or Geriatric Nursing
Volume 25
Number 2
whether sensory changes lead inevitably to compromised nutritional status is unclear. Research doesn’t show a causal relationship between decreased taste and smell acuity and malnutrition. Elders continue to report decreased appetite and taste changes as a reason for not eating, especially in long-term care institutions, and caregivers help provide them with good nutrition care. CAREGIVERS CAN HELP Elderly people sometimes report that food tastes unpleasant or bitter. This reaction may be an oral condition that can be helped by brushing the tongue and rinsing the mouth. Oral conditions affecting composition and amount of saliva also can affect flavor perception. Modification of individual foods adds appeal, “mouth feel,” and extra flavor to compensate for loss of taste and smell. Herbs, spices, and flavoring can be added to food during cooking or directly at the table. A little hot sauce on eggs or lemon juice on vegetables perks up the flavor. Adding texture to food with nuts, fruit bits like raisins, crushed cereal, or crackers and leaving larger pieces in mashed food adds what is called “mouth feel” that enhances its appeal even though it doesn’t add flavor. Serving cold foods cool but not ice cold enhances flavor, as does serving foods at a range of temperatures for variety. Making food colorful adds interest and makes it more attractive to eat. That’s the idea behind parsley garnishes and pools of sauce with squiggly designs that are so popular in restaurants. Chewing food well brings out maximum flavor and aids digestion. Smoking and regular consumption of strongly flavored things, like coffee, reduces the ability to perceive flavors, so elders can be encouraged to modify these habits. REFERENCES 1. Doty RL, Shaman P, Applebaum SL, et al. Smell identification ability: changes with age. Science 1984;226:1441-3. 2. Hoffman HJ, Ishii EK, Macturk RH. Age-related changes in the prevalence of smell/taste problems among the United States adult population. Results of the 1994 Disability supplement to the National Health Interview Survey (NHIS). Ann N Y Acad Sci 1998;855:716-22. 3. Mattes RD, Cowart BJ. Dietary assessment of patients with chemosensory disorders. J Am Diet Assoc 1994;94:50-6.
PEGGY K.YEN, RD, MPH, is a nutrition consultant in the cardiovascular health and nutrition division of the Family Health Administration in the Maryland Department of Health and Mental Hygiene in Baltimore. 0197-4572/$ - see front matter © 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.gerinurse.2003.12.011
March/April 2004
119