The sense of taste has to be one of the most important human senses. It gives an individual the ability to recognize consumables that are encountered on a regular basis such as a favorite steak platter or a favorite wine. However, when that individual reaches a particular age the sense of taste deteriorates, which can result in potentially dangerous conditions such as malnourishment or susceptibility to diseases. This problem of taste loss due to aging needs to be studied more because it can effect both the physical and mental health of many elderly people.

When elderly individuals try to live life with a weakened ability to recognize certain food flavors or any other consumable item, their dietary needs can be greatly affected. A certain number of foods are not going to taste good enough to satisfy the appetites of the elderly, so they might resort to using unhealthy eating habits. For example, they could lose the motivation to eat certain foods such as vegetables or meats and increase the consumption of foods that are low in nutritional value such as candies or pastries. This shift can result in health problems such as a loss in bone mass, a weakened immune system, weak muscles, and high blood pressure.

Elderly citizens need to acquire a specific amount of nutrients in order to maintain a healthy life style. Spence (1989) mentioned that diets which maintain adequate levels of vitamins and minerals and also consist of 50 to 55% carbohydrates, 12 to 15% proteins, and 25 to 35% fats are recommended for persons over the age of 50. In order for the elderly to live up to a healthy diet, they need to consume nutritious foods that will taste good to them. The problem with this situation is how to handle the effects of age on the sense of taste.

There have been numerous studies (e. g. Hendricks, Calasanti, and Turner, 1988; Schieber, 1992) in the past that have searched for possible causes and solutions to taste loss in aging people. Some researchers have looked for causes of taste loss in the elderly by focusing on the biological changes that occur in the mouth such as enhanced taste abilities or sensory deficits in the tongue, while others have looked for causes of taste loss by focusing on the impact of external factors on the mouth such as smoking (e. g. Hsu and Davis, 1981). Those that have searched for solutions to the problem of taste loss in the elderly have experimented with flavor or color enhancers in foods for the purpose of making them more appealing to the elderly. Surprisingly, some past research has made progress in finding possible explanations for the decline in taste ability in the elderly (e. g. Miller, 1988).

Some researchers have attempted to determine the cause of taste loss in the elderly by focusing specifically on the sensitivity of the tongue (e. g. Schiffman, 1977). Some have speculated that the decline of taste could be related to the number of taste buds that a person loses on the surface of his tongue when he reaches a certain age (e. g. Schieber, 1992). Scientists have known that as a person's tongue ages it will naturally lose taste buds. Hendricks, Calasanti and Turner (1988) noted that the number of taste buds on the tongue do stay constant until the age of fifty when their numbers begin to decline. When this happens, any certain number of taste buds could be lost, thus causing a decrease in taste ability.

The issue of just how many taste buds an individual loses due to aging has been a major debate. Schieber (1992) states that several scientists estimated that a person could lose 20 to 60% of their taste buds after the age of 60. Schiffman (1977) mentioned that three scientists found that the average number of taste buds declines dramatically from 208 buds to 88 buds when a person reaches the age of 74. Research and debates over how many taste buds a person could lose continues.

A smaller number of taste buds may provide some insight as to why the elderly are only capable of recognizing the flavors of certain foods. The density in their taste buds, however, could provide even better insight to this problem. Researchers have speculated about whether or not a person's taste bud density changes as he or she ages causing gradual changes in the ability to recognize certain flavors of foods. Miller (1988) found in one of his studies that taste bud density does not really diminish with age, but rather it stays at an equal level based on person's individual health. In this case, a person's health could influence taste sensitivity.

While some researchers continue to focus their attention on the density of or the decline of taste buds as a possible cause for the loss in taste ability, one focused his studies on the tongue's ability to produce adequate amounts of saliva in the mouth (e. g. Spence, 1989). Spence mentioned that a reduction in saliva could interfere with a dissolving food's reaction with receptor cells on the tongue. This information, in turn, could explain why some foods taste dry to some elderly individuals.

There are other factors besides aging that can contribute to a gradual loss of or distortion of taste in the elderly. Some external factors that can effect the mouth have been suspected of or known to cause taste buds to decline in number. Smoking, for example, has been suspected of either inhibiting or destroying the mouth's ability to function properly. Hsu and Davis (1981) found that smoking, along with certain diseases, can decrease gustatory sensitivity significantly. Schiffman (1997) noted that drugs that are secreted into the saliva can exert adverse effects on the taste system either by modifying taste transduction mechanisms or by producing a taste of their own.

Although the elderly can lose a certain number of taste buds on their tongue, they may still able to recognize certain flavors. Additives (such as salt, for example) can still be recognize fairly well by the elderly. Spitzer (1986) found that young men, aged 18 to 25 years old, had significantly lower salt thresholds than institutionalized and non-institutionalized elderly men. This meant that the elderly subjects senses were able to create a response to the flavor of salt, but their response to salt was not as strong as the younger participants' response.

The reason why the elderly can recognize certain flavors very well is due to the fact that several of the main taste abilities become relatively strong when the other abilities weaken as they age. Cunningham and Brookbank (1988) noted that the threshold levels for the four primary taste qualities: salty, sweet, bitter, and sour do increase in elderly individuals. There is evidence to support this fact. Schiffman (1977) mentioned that previous research has found that sucrose threshold for persons from 52-85 years of age is three times higher than for persons 15-19.

This increase in threshold for the four primary taste qualities can greatly affect the nutritional status of the elderly. As mentioned earlier, their ability to recognize flavors in foods might affect the types of foods that they will eat. Briley (1994) mentioned in one study that the most common foods consumed by elderly Americans were white bread, ground coffee, whole milk, sugar, potatoes, tea, orange juice, eggs both fried and prepared in other ways, butter, and bacon. Some of these foods (such as bacon or fried eggs) could result in high cholesterol or high blood pressure in the elderly if consumed in high amounts.

Biological research may have found several possible causes as to why taste deteriorates in an aging person, but a treatment for the problem still remains to be found. Schiffman (1997) mentioned that there are no proven pharmacological methods to treat age-related chemosensory decrements, and the prognosis for the recovery of smell and taste sensations is poor. In order to make the taste of food more enjoyable, treating the tongue may not be the solution.

One way to correct this problem has been to use flavor amplifiers in foods. This involves improving a food by adding an extra ingredient to it such as bacon seasoning or serving it with a sauce such as cream gravy. This has been a subject of experimentation for a while (Clydesdale, 1994). Clydesdale mentioned that color plays a key role in food choice by influencing taste thresholds, sweetness perception, food preference, pleasantness, and acceptability. Clydesdale tested this idea on both young and elderly people by having them taste a specially flavored and colored beverage. Clydesdale discovered that a change in sucrose concentration had a strong effect on all the sensory responses studied for both populations.

Some governments around the world (e. g. Japan) have attempted to improve nutrition in the elderly by implementing programs that can help encourage food consumption in the elderly despite their aging ability to taste well. Matsutami (1992) mentioned that the Japanese Ministry of Health and Welfare established in 1990 the "Eating Habit Guidelines for the Elderly" which points out the need for the aged to be wary of under-nutrition. Many of these guidelines encourage regular food consumption in order to live a better life.

The issue of age related taste changes is still a problem for the elderly around the world and will be a problem for many more people in 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 ability to enjoy certain foods will come to an end. It is imperative that adults of today become aware of this situation since this age-related change could affect their health when they reach the age of 60.

A lot of researchers have looked for causes of and solutions to this problem and many have found interesting results. More research on this subject, however, should be conducted in the near future. If more research is conducted on this problem, then the chances of finding a better way to improve taste functioning in the elderly could occur. The human sense of taste is a strong ability to have and keeping it strong for future generations is important is important for the survival of the human race as a whole.

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Clydesdale, F.M., (1994). Changes in color and favor and their effects 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: Harper and 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 Geriatric Nutrition. New Jersey: Noyes Publications.

Matsutani, M. (1992). Foods suitable for the elderly. Nutrition Reviews, 50 (12), 72-75.

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Schieber, F. (1992). Aging and the senses. In J. E. Birren, R. B. Sloane, & G. D. Cohen (Eds.), Handbook of mental health and aging. San Diego: Academic Press Inc.

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Schiffman, S. (1997). Taste and smell loss in normal aging and disease. 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 non institutionalized elderly men. Psychological Sciences, 43 (3), 71-74.