Effects of age and removable artificial dentition on taste

Does presbygeusia really exist? An updated narrative review

This review critically assessed the existence of presbygeusia, i.e., the impairment in taste perception occurring in the elderly, as a natural part of the aging process and its potential clinical implications. Several factors might contribute to age-related taste alterations (TAs), including structural changes in taste buds, alterations in saliva composition, central nervous system changes, and oral microbiota dysbiosis. A comprehensive literature review was conducted to disentangle the effects of age from those of the several age-related diseases or conditions promoting TAs. Most of the included studies reported TAs in healthy elderly people, suggesting that presbygeusia is a relatively frequent condition associated with age-related changes in the absence of pathological conditions. However, the impact of TAs on dietary preferences and food choices among the elderly seems to be less relevant when compared to other factors, such as cultural, psychological, and social influences. In conclusion, presbygeusia exists even in the absence of comorbidities or drug side effects, but its impact on dietary choices in the elderly is likely modest.

Evaluation of different taste sensations along with body mass index (BMI) in geriatric patients with and without complete dentures

BACKGROUND

The purpose of this study was to investigate the effect of acrylic full removable dentures on the perception of four primary tastes (sweet, sour, salty, and bitter), as well as to determine if there is a correlation between changes in body mass index (BMI) and taste perception.

MATERIALS AND METHODS

A total of 60 patients who wore acrylic removable dentures and 60 controls were included in the study as a convenient sample. Sixteen solutions for basic tastes were prepared, and the patients were asked to identify the taste of each solution from the lowest concentration. Anthropometric measures, such as height and weight, were measured and recorded in an MS-Excel sheet. The data were analyzed using SPSS version 23.

RESULTS

The results showed that patients with complete removable dentures had lower taste scores for sourness (P < 0.001) and sweetness (P < 0.001) compared to the control group. However, there was no significant difference in salt taste scores (P = 0.218) and bitterness (P = 0.002) between the two groups. Additionally, the study found a correlation between lower BMI values and higher taste scores among denture-wearing patients, indicating an inverse relationship between total taste scores and BMI.

CONCLUSIONS

The study suggests that geriatric patients with complete dentures have reduced taste sensations compared to those without dentures which can have a negative impact on their nutritional status. Therefore, it is crucial to provide adequate nutritional support and dietary counseling for geriatric patients based on health policy to maintain their overall health and well-being.

Differences in time-intensity sensory profiles of sweet taste intensity of glucose between older and young adults

Background

To understand age-related changes in sweet taste perception in daily life, it is important to understand taste intensity at the suprathreshold level. Previous studies have attempted to characterize the temporal aspects of human taste perception in terms of time-intensity evaluations. The perception of dynamic taste intensity in older adults increases slowly for salty taste; however, there have been no previous studies on time-intensity sensory evaluation of sweet taste in older adults. We hypothesized that older adults perceive sweet taste intensity more slowly than young adults.

Methods

Fifty young and 40 older adults participated in the study and glucose solutions of 0.6 M and 1.5 M were used as stimuli. The study comprised two experiments: (1) a cup tasting test (static taste perception in the mouth), and (2) a time-intensity sensory evaluation, in which the solutions were presented using a custom-made delivery system. The intra-oral device was made to fit each participant's dentition. Further, the level of gag reflex was taken into consideration for each participant in the design of the intra-oral device. A suction tube was placed across the posterior tongue near the throat to remove solution and saliva. The solution delivery system was controlled by an original computer program.

Results

Older adults presented significantly different maximum intensity timing and slope for both concentrations compared with young adults (slope for 1.5 M, p < 0.01; others, p < 0.05). No significant differences were found between the older and young adults for reaction timing and maximum intensity.

Conclusion

We conclude that older adults perceived sweetness more slowly than young adults, and ultimately perceived almost the same intensity as young adults. This is the first reported characterization of the time-intensity profile of sweet taste intensity of glucose in older adults. Using a standardized system enabled us to assess and compare feedback on taste intensities among different age groups in real-time. Based on this, we recommend older adults "savor" to perceive sweet tastes at the same level experienced by young adults.

Taste Perception and Water Swallow Screen Results in Old-Old Women

Changes in both swallowing and taste commonly occur in advanced age, though the relationship between the two is unknown. This study examined the association between a water swallow screen test and taste identification and intensity rating. Participants included 47 community-dwelling women aged 85–94 years. Participants completed three trials of a water swallow screen and were observed for signs of aspiration, which, if present, indicated failure. Four pure taste stimuli at low and high concentrations and water were presented, and participants selected one of five taste labels and rated their intensity on the generalized Labeled Magnitude Scale. Ratios of intensity ratings were computed for each taste stimulus to compare the perception of low and high concentrations. The association between water swallow screen failure, correct taste identification, and taste intensity ratio was evaluated with logistic regression modeling, with mediating factors of frailty and number of comorbidities. Failure of three water swallow screen trials was associated with a higher taste intensity ratio for caffeine (bitter) and a lower taste intensity ratio for sucrose (sweet). Correct identification of taste, frailty, and number of comorbidities were not associated with failure of any number of water swallow screen trials. Intensity ratings of certain tastes may be associated with swallowing in old-old women. Heightened vigilance in this population may be necessary to prevent complications related to dietary intake.

Longitudinal study of factors affecting taste sense decline in old-old individuals

The sense of taste plays a pivotal role for personal assessment of the nutritional value, safety and quality of foods. Although it is commonly recognised that taste sensitivity decreases with age, alterations in that sensitivity over time in an old-old population have not been previously reported. Furthermore, no known studies utilised comprehensive variables regarding taste changes and related factors for assessments. Here, we report novel findings from a 3-year longitudinal study model aimed to elucidate taste sensitivity decline and its related factors in old-old individuals. We utilised 621 subjects aged 79-81 years who participated in the Septuagenarians, Octogenarians, Nonagenarians Investigation with Centenarians Study for baseline assessments performed in 2011 and 2012, and then conducted follow-up assessments 3 years later in 328 of those. Assessment of general health, an oral examination and determination of taste sensitivity were performed for each. We also evaluated cognitive function using Montreal Cognitive Assessment findings, then excluded from analysis those with a score lower than 20 in order to secure the validity and reliability of the subjects' answers. Contributing variables were selected using univariate analysis, then analysed with multivariate logistic regression analysis. We found that males showed significantly greater declines in taste sensitivity for sweet and sour tastes than females. Additionally, subjects with lower cognitive scores showed a significantly greater taste decrease for salty in multivariate analysis. In conclusion, our longitudinal study revealed that gender and cognitive status are major factors affecting taste sensitivity in geriatric individuals.

Factors related to taste sensitivity in elderly: cross-sectional findings from SONIC study

The sense of taste is important, as it allows for assessment of nutritional value, as well as safety and quality of foods, with several factors suggested to be associated with taste sensitivity. However, comprehensive variables regarding taste and related factors have not been utilised in previous studies for assessments of sensitivity. In the present study, we performed cross-sectional analyses of taste sensitivity and related factors in geriatric individuals who participated in the SONIC Study. We analysed 2 groups divided by age, 69-71 years (young-old, n = 687) and 79-81 years (old-old, n = 621), and performed a general health assessment, an oral examination and determination of taste sensitivity. Contributing variables were selected by univariate analysis and then subjected to multivariate logistic regression analysis. In both groups, females showed significantly better sensitivity for bitter and sour tastes. Additionally, higher cognitive scores for subjects with a fine taste for salty were commonly seen in both groups, while smoking, drinking, hypertension, number of teeth, stimulated salivary flow salt intake and years of education were also shown to be associated with taste sensitivity. We found gender and cognitive status to be major factors affecting taste sensitivity in geriatric individuals.

Ageing and taste

Taste perception has been studied frequently in young and older adult groups. This paper systematically reviews these studies to determine the effect of ageing on taste perception and establish the reported extent of sensory decline. Five databases were searched from 1900 to April 2012. Articles relating to healthy ageing in human subjects were included, reviewed and rated (Downs and Black scoring system). Sixty-nine studies investigated the effect of ageing on taste perception; forty examined detection thresholds of which twenty-three provided sufficient data for meta-analysis, eighteen reported identification thresholds and twenty-five considered supra-threshold intensity perception. Researchers investigating detection thresholds considered between one and thirteen taste compounds per paper. Overall, the consensus was that taste detection thresholds increased with age (Hedges’ g = 0·91, P < 0·001), across all taste modalities. Identification thresholds were reported to be higher for older adults in seventeen out of eighteen studies. Sixteen out of twenty-five studies reported perception of taste intensity at supra-threshold levels to be significantly lower for older adults. However, six out of nine studies concerning sucrose found perceived intensity of sweet taste not to diminish with age. The findings of this systematic review suggest taste perception declines during the healthy ageing process, although the extent of decline varies between studies. Overall, the studies reviewed had low Downs and Black scores (mean 16 (SD 2)) highlighting the need for more robust large scale and longitudinal studies monitoring the impact of ageing on the sensory system, and how this influences the perception of foods and beverages.

The impact of oral health on taste ability in acutely hospitalized elderly

Objective

To investigate to what extent various oral health variables are associated with taste ability in acutely hospitalized elderly.

Background

Impaired taste may contribute to weight loss in elderly. Many frail elderly have poor oral health characterized by caries, poor oral hygiene, and dry mouth. However, the possible influence of such factors on taste ability in acutely hospitalized elderly has not been investigated.

Materials and Methods

The study was cross-sectional. A total of 174 (55 men) acutely hospitalized elderly, coming from their own homes and with adequate cognitive function, were included. Dental status, decayed teeth, oral bacteria, oral hygiene, dry mouth and tongue changes were recorded. Growth of oral bacteria was assessed with CRT® Bacteria Kit. Taste ability was evaluated with 16 taste strips impregnated with sweet, sour, salty and bitter taste solutions in 4 concentrations each. Correct identification was given score 1, and maximum total taste score was 16.

Results

Mean age was 84 yrs. (range 70–103 yrs.). Total taste score was significantly and markedly reduced in patients with decayed teeth, poor oral hygiene, high growth of oral bacteria and dry mouth. Sweet and salty taste were particularly impaired in patients with dry mouth. Sour taste was impaired in patients with high growth of oral bacteria.

Conclusion

This study shows that taste ability was reduced in acutely hospitalized elderly with caries activity, high growth of oral bacteria, poor oral hygiene, and dry mouth. Our findings indicate that good oral health is important for adequate gustatory function. Maintaining proper oral hygiene in hospitalized elderly should therefore get high priority among hospital staff.

Optimal preferred MSG concentration in potatoes, spinach and beef and their effect on intake in institutionalized elderly people

BACKGROUND

Elderly people may benefit from sensory stimulation to increase food intake since anorexia of ageing is prevalent among them. An optimal MSG concentration may increase the palatability of foods but this depends on the food and chemosensory status of the taster. Currently, the results on taste enhancing to increase intake are inconsistent.

OBJECTIVE

To find an optimal preferred MSG concentration in mashed potatoes, spinach and ground beef and to determine whether this concentration increases consumption of these foods among institutionalized elderly people.

DESIGN

Single blind within subject cross-over study performed at the laboratory and in the residents' own apartments.

PARTICIPANTS

33 elderly and 29 young people in the sensory study and 53 elderly people in the intake study.

MEASUREMENTS

Pleasantness of the foods was rated of the foods each with 0, 0.5, 0.8, 1.3 and 2.0 g of MSG/100g. Intake was measured by weighing back leftovers of 2 meals with MSG (0.5% in mashed potatoes, 2% in spinach and ground meat) and without MSG.

RESULTS

0.5% MSG (p < 0.05) was preferred in mashed potatoes but no optimal preferred concentration was found for spinach and ground beef, possibly because of their complex taste. Intake was not different between the foods with and without MSG or the total meal (all p > 0.68).

CONCLUSION

MSG (0.5% and 2%) does not guarantee a higher intake among elderly. The chemosensory heterogeneity of the elderly population requires more individual flavor enhancement to improve the dietary intake and sensory experience.

No effect of 16 weeks flavor enhancement on dietary intake and nutritional status of nursing home elderly

There is a lack of data to support the long-term effect of flavor enhancement on food intake and nutritional status. Our aim was to determine if daily addition of 700 mg flavor and/or 300 mg monosodium glutamate (MSG) to the animal protein part of the cooked meal for 16 weeks leads to an increase in energy intake and in body weight in nursing home elderly. We performed a single blind randomized 16 weeks parallel study consisting of a control group (n=23), a MSG group (n=19), a flavor group (n=19) and a flavor plus MSG group (n=22). Main outcome measures were intake of the cooked meal, which was measured by weighing back leftovers during 14 days and body weight. Both were measured before and at the end of the intervention period. After 16 weeks, energy intake and body weight did not increase within the control group, the flavor group, the flavor plus MSG group and the MSG group. Between the groups, no differences were found in changes in energy intake and body weight. Enhancing the taste of a cooked meal with flavor and/or MSG does not lead to a higher energy intake and body weight among nursing home elderly. More research is needed to determine the efficacy of flavor enhancement on intake and nutritional status.

Oral health, taste, and olfaction

Oral health, taste, and smell are critical components to an older person's overall sense of well-being and quality of life. Oral health problems can cause pain and discomfort and can hinder the maintenance of a satisfying and nutritious diet. Loss of taste and smell interferes with pleasure derived from food and food-related activities. Attention should be given to preserving teeth and optimizing oral function. Likewise, close evaluation of older adults' medications may identify the causes of taste and smell disorders. In instances in which nutrient intake is inadequate and chemosensory perception is considered a likely contributor, a trial of flavor enhancers or monosodium glutamate may improve both quality and quantity of intake. Much more information is needed to understand the interrelationship between chemosensory perception, food intake regulatory mechanisms, and nutritional status. Multidisciplinary studies will be required to understand how to improve nutrition through manipulation of oral characteristics, taste, and smell.

Testing toothbrushing ability of elderly patients

An individual's ability to perform adequate oral care may become jeopardized by medical and physical insults associated with the aging process. Declines in oral care abilities may be difficult to identify, and usually go unnoticed and unaddressed. This study examined a tool developed to assess toothbrushing ability in elderly patients. The Toothbrushing Ability Test (TAT) was examined for its ability to predict brushing effectiveness (measured by plaque levels) and to determine its interrater and intrarater reliability. Fifty-eight dentate subjects, age 65 and older, from the Portland Veterans Affairs Medical Center and a community nursing home participated. Results showed highly significant Spearman correlations between TAT scores and plaque levels (r = 0.719; p < 0.000). Correlations also revealed high interrater (r = 0.87) and intrarater reliability (r = 0.82). The results suggest that the TAT is a practical and effective screening tool for assessing oral self-care ability in the elderly.