The sense of taste has to be one of the most important humansenses. It gives an individual the ability to recognize consumablesthat are encountered on a regular basis such as a favorite steakplatter or a favorite wine. However, when that individual reaches aparticular age the sense of taste deteriorates, which can result inpotentially dangerous conditions such as malnourishment orsusceptibility to diseases. This problem of taste loss due to agingneeds to be studied more because it can effect both the physical andmental health of many elderly people.
When elderly individuals try to live life with a weakened abilityto recognize certain food flavors or any other consumable item, theirdietary needs can be greatly affected. A certain number of foods arenot going to taste good enough to satisfy the appetites of theelderly, so they might resort to using unhealthy eating habits. Forexample, they could lose the motivation to eat certain foods such asvegetables or meats and increase the consumption of foods that arelow in nutritional value such as candies or pastries. This shift canresult in health problems such as a loss in bone mass, a weakenedimmune system, weak muscles, and high blood pressure.
Elderly citizens need to acquire a specific amount of nutrients inorder to maintain a healthy life style. Spence (1989) mentioned thatdiets which maintain adequate levels of vitamins and minerals andalso consist of 50 to 55% carbohydrates, 12 to 15% proteins, and 25to 35% fats are recommended for persons over the age of 50. In orderfor the elderly to live up to a healthy diet, they need to consumenutritious foods that will taste good to them. The problem with thissituation is how to handle the effects of age on the sense oftaste.
There have been numerous studies (e. g. Hendricks, Calasanti, andTurner, 1988; Schieber, 1992) in the past that have searched forpossible causes and solutions to taste loss in aging people. Someresearchers have looked for causes of taste loss in the elderly byfocusing on the biological changes that occur in the mouth such asenhanced taste abilities or sensory deficits in the tongue, whileothers have looked for causes of taste loss by focusing on the impactof external factors on the mouth such as smoking (e. g. Hsu andDavis, 1981). Those that have searched for solutions to the problemof taste loss in the elderly have experimented with flavor or colorenhancers in foods for the purpose of making them more appealing tothe elderly. Surprisingly, some past research has made progress infinding possible explanations for the decline in taste ability in theelderly (e. g. Miller, 1988).
Some researchers have attempted to determine the cause of tasteloss in the elderly by focusing specifically on the sensitivity ofthe tongue (e. g. Schiffman, 1977). Some have speculated that thedecline of taste could be related to the number of taste buds that aperson loses on the surface of his tongue when he reaches a certainage (e. g. Schieber, 1992). Scientists have known that as a person'stongue ages it will naturally lose taste buds. Hendricks, Calasantiand Turner (1988) noted that the number of taste buds on the tonguedo stay constant until the age of fifty when their numbers begin todecline. When this happens, any certain number of taste buds could belost, thus causing a decrease in taste ability.
The issue of just how many taste buds an individual loses due toaging has been a major debate. Schieber (1992) states that severalscientists estimated that a person could lose 20 to 60% of theirtaste buds after the age of 60. Schiffman (1977) mentioned that threescientists found that the average number of taste buds declinesdramatically from 208 buds to 88 buds when a person reaches the ageof 74. Research and debates over how many taste buds a person couldlose continues.
A smaller number of taste buds may provide some insight as to whythe elderly are only capable of recognizing the flavors of certainfoods. The density in their taste buds, however, could provide evenbetter insight to this problem. Researchers have speculated aboutwhether or not a person's taste bud density changes as he or she agescausing gradual changes in the ability to recognize certain flavorsof foods. Miller (1988) found in one of his studies that taste buddensity does not really diminish with age, but rather it stays at anequal level based on person's individual health. In this case, aperson's health could influence taste sensitivity.
While some researchers continue to focus their attention on thedensity of or the decline of taste buds as a possible cause for theloss in taste ability, one focused his studies on the tongue'sability to produce adequate amounts of saliva in the mouth (e. g.Spence, 1989). Spence mentioned that a reduction in saliva couldinterfere with a dissolving food's reaction with receptor cells onthe tongue. This information, in turn, could explain why some foodstaste dry to some elderly individuals.
There are other factors besides aging that can contribute to agradual loss of or distortion of taste in the elderly. Some externalfactors that can effect the mouth have been suspected of or known tocause taste buds to decline in number. Smoking, for example, has beensuspected of either inhibiting or destroying the mouth's ability tofunction properly. Hsu and Davis (1981) found that smoking, alongwith certain diseases, can decrease gustatory sensitivitysignificantly. Schiffman (1997) noted that drugs that are secretedinto the saliva can exert adverse effects on the taste system eitherby modifying taste transduction mechanisms or by producing a taste oftheir own.
Although the elderly can lose a certain number of taste buds ontheir tongue, they may still able to recognize certain flavors.Additives (such as salt, for example) can still be recognize fairlywell by the elderly. Spitzer (1986) found that young men, aged 18 to25 years old, had significantly lower salt thresholds thaninstitutionalized and non-institutionalized elderly men. This meantthat the elderly subjects senses were able to create a response tothe flavor of salt, but their response to salt was not as strong asthe younger participants' response.
The reason why the elderly can recognize certain flavors very wellis due to the fact that several of the main taste abilities becomerelatively strong when the other abilities weaken as they age.Cunningham and Brookbank (1988) noted that the threshold levels forthe four primary taste qualities: salty, sweet, bitter, and sour doincrease in elderly individuals. There is evidence to support thisfact. Schiffman (1977) mentioned that previous research has foundthat sucrose threshold for persons from 52-85 years of age is threetimes higher than for persons 15-19.
This increase in threshold for the four primary taste qualitiescan greatly affect the nutritional status of the elderly. Asmentioned earlier, their ability to recognize flavors in foods mightaffect the types of foods that they will eat. Briley (1994) mentionedin one study that the most common foods consumed by elderly Americanswere white bread, ground coffee, whole milk, sugar, potatoes, tea,orange juice, eggs both fried and prepared in other ways, butter, andbacon. Some of these foods (such as bacon or fried eggs) could resultin high cholesterol or high blood pressure in the elderly if consumedin high amounts.
Biological research may have found several possible causes as towhy taste deteriorates in an aging person, but a treatment for theproblem still remains to be found. Schiffman (1997) mentioned thatthere are no proven pharmacological methods to treat age-relatedchemosensory decrements, and the prognosis for the recovery of smelland taste sensations is poor. In order to make the taste of food moreenjoyable, treating the tongue may not be the solution.
One way to correct this problem has been to use flavor amplifiersin foods. This involves improving a food by adding an extraingredient to it such as bacon seasoning or serving it with a saucesuch as cream gravy. This has been a subject of experimentation for awhile (Clydesdale, 1994). Clydesdale mentioned that color plays a keyrole in food choice by influencing taste thresholds, sweetnessperception, food preference, pleasantness, and acceptability.Clydesdale tested this idea on both young and elderly people byhaving them taste a specially flavored and colored beverage.Clydesdale discovered that a change in sucrose concentration had astrong effect on all the sensory responses studied for bothpopulations.
Some governments around the world (e. g. Japan) have attempted toimprove nutrition in the elderly by implementing programs that canhelp encourage food consumption in the elderly despite their agingability to taste well. Matsutami (1992) mentioned that the JapaneseMinistry of Health and Welfare established in 1990 the "Eating HabitGuidelines for the Elderly" which points out the need for the aged tobe wary of under-nutrition. Many of these guidelines encourageregular food consumption in order to live a better life.
The issue of age related taste changes is still a problem for theelderly around the world and will be a problem for many more peoplein the future. Schiffman (1997) mentioned that by the year 2030, 20%of the U.S. population (69.4 million) will be older than 65 years.This means that millions of adults may not realize that their abilityto enjoy certain foods will come to an end. It is imperative thatadults of today become aware of this situation since this age-relatedchange could affect their health when they reach the age of 60.
A lot of researchers have looked for causes of and solutions tothis problem and many have found interesting results. More researchon this subject, however, should be conducted in the near future. Ifmore research is conducted on this problem, then the chances offinding a better way to improve taste functioning in the elderlycould occur. The human sense of taste is a strong ability to have andkeeping it strong for future generations is important is importantfor the survival of the human race as a whole.
Briley, M.E., (1994). Food preferences of the elderly.Nutrition Reviews, 52 (8), 21-22.
Clydesdale, F.M., (1994). Changes in color and favor and theireffects on sensory perception in the elderly. Nutrition Reviews,52 (8), 19-20.
Cunningham, W.R. & Brookbank, J. W., (1988). Gerontology:The Psychology, Biology, and Sociology of Aging. New York: Harperand Row Publishers.
Hendricks, J., Calasanti, T. M., & Turner, H. B. (1988).Foodways of the elderly. American Behavioral Scientist, 32(1), 61-68.
Hsu, J. & Davis, R. (1981). Handbook of GeriatricNutrition. New Jersey: Noyes Publications.
Matsutani, M. (1992). Foods suitable for the elderly. NutritionReviews, 50 (12), 72-75.
Miller, J. (1988). Human taste bud density across adult agegroups. Journal of Gerontology, 43 (1), 26-30.
Schieber, F. (1992). Aging and the senses. In J. E. Birren, R. B.Sloane, & G. D. Cohen (Eds.), Handbook of mental health andaging. San Diego: Academic Press Inc.
Schiffman, S. (1977). Food recognition by the elderly. Journalof Gerontology, 32 (5), 586-592.
Schiffman, S. (1994). Changes in taste and smell: Druginteractions and food preferences. Nutrition Reviews, 52 (8),11-14.
Schiffman, S. (1997). Taste and smell loss in normal aging anddisease. Journal of the American Medical Association, 278(16), 1357-1362.
Spence, A. P. (1989). Biology of human aging. New Jersey:Prentice Hall.
Spitzer, M. E. (1986). Taste acuity in institutionalized and noninstitutionalized elderly men. Psychological Sciences, 43 (3),71-74.