Taste disorders: a survey of the examination methods and treatments used in Japan

Taste loss in cancer patients: clinicians' perceptions of educational materials and diagnostic tools

PURPOSE

Cancer therapy is essential and lifesaving; however, it can have short- and long-term consequences on patients' health. Up to 87% of cancer patients report changes in taste function, yet patients report a lack of support from clinicians regarding their experience with taste loss during and following treatment. Thus, the objective of this study was to assess clinicians' knowledge and experience with managing patients with taste loss and identify potential gaps in the availability of educational materials and diagnostic tools.

METHOD

In an online survey, sixty-seven participants who identify as clinicians and practice in the United States and work with cancer patients that complain of taste problems answered questions on their knowledge and experience supporting cancer patients experiencing changes in taste function and provided their opinion on access to educational materials.

RESULTS

The current study reports gaps in participants' knowledge of taste and taste disorder terminology, with 15.4% correctly defining both taste and flavor and roughly half were familiar with specific taste disorder classifications. Over half of the participants reported not having access to adequate information to help their patients manage taste alterations. Only two-thirds of participants reported routinely asking patients if they are experiencing changes in taste function.

CONCLUSION

Clinicians' responses emphasized the need to improve access to educational materials regarding taste changes and increase the availability of information regarding management strategies. Addressing these inequities in education and improving the standard of care is the first step in improving the care for cancer patients suffering from altered taste function.

Resting Saliva Volume as a Risk Factor for Hypogeusia: A Retrospective Study

OBJECTIVES

The causes of hypogeusia include zinc deficiency, systemic illness, and consumption of drugs. Notably, patients with oral cavity diseases such as oral candidiasis and salivary gland hypofunction may present with risk factors that remain unreported. Hence, this study aimed to investigate the relationship between age, sex, smoking status, serum zinc concentration, oral candidiasis, saliva volume, and taste function in patients with hypogeusia.

SUBJECTS AND METHODS

Overall, 335 participants who complained of taste abnormalities underwent a taste test. Based on the recognition threshold value, the participants were classified as normal individuals (recognition threshold of 1 and 2) and patients with hypogeusia (recognition threshold of ≥3). The clinical characteristics, including resting saliva volume (RSV) and stimulated saliva volume (SSV), were compared, and a multivariate logistic regression analysis focusing on RSV was performed.

RESULTS

Patients with hypogeusia had a lower RSV than normal individuals for all tastes, but not for SSV. Based on the results of regression analysis, RSV was identified as an independent predictor of hypogeusia for salty and bitter tastes. Moreover, the proportion of patients with decreased RSV increased as the number of taste qualities exceeding the reference recognition threshold increased. Furthermore, a decrease in RSV was associated with an increase in the recognition threshold for salty and bitter tastes.

CONCLUSIONS

Based on the results of the present study, moisturizing the oral cavity may be useful against hypogeusia.

Retrospective study on the therapeutic efficacy of zinc acetate hydrate administration to patients with hypozincemia-induced dysgeusia

BACKGROUND

Dysgeusia is a relatively early symptom of zinc deficiency, and zinc replacement is effective in treating dysgeusia. The administration of zinc acetate hydrate (ZAH) was approved in 2017 for patients with hypozincemia in Japan. This retrospective study was conducted to explore the efficacy and safety of ZAH administration in patients with hypozincemia-induced dysgeusia.

METHODS

Patients with hypozincemia-induced dysgeusia who visited our hospital from May 2013 to December 2019 were included in this study. ZAH (zinc content; 50 mg/day) was administered to 42 patients for 24 weeks. The taste test was performed using the filter paper disk method, and the total cognitive thresholds of the left and right chorda tympani regions were used. Changes in taste function, serum zinc and copper levels, and copper/zinc ratio were analyzed. A total of 28 patients who received polaprezinc (PPZ, zinc content; 34 mg/day) for 24 weeks, who were prescribed until ZAH was approved, were registered as controls.

RESULTS

Serum zinc levels at 12 and 24 weeks after ZAH or PPZ administration were higher than those before administration. These levels were significantly higher in the ZAH-treated group than in the PPZ-treated group. However, serum copper levels did not significantly change before and after administration. In the taste test, the taste thresholds for the acidity and salty at 12 and 24 weeks after ZAH administration were significantly decreased compared to before administration. In contrast, in the PPZ group, the taste thresholds for the acidity and salty were significantly decreased 24 weeks after administration.

CONCLUSIONS

ZAH (50 mg/day) administration was effective in improving the gustatory sensitivity of patients with dysgeusia and hypozincemia 12 weeks after administration without affecting the serum copper level. ZAH was also more effective than PPZ.

Ethyl loflazepate as a treatment for patients with idiopathic and psychogenic taste disorder

Background

Ethyl loflazepate (EL) is a benzodiazepine derivative that has been reported to activate the gustatory cortex. Our department routinely uses EL as a first-line treatment for idiopathic and psychogenic taste disorders, although little has been reported in the literature with respect to patient outcomes, so we conducted a retrospective study examining its safety and efficacy.

Methods

Between 2008 and 2020, 49 patients (14 males and 35 females; mean age, 62.1 years) were diagnosed with taste disorders and received EL as their only treatment for > 14 days. Severity of taste disorder was evaluated using the paper disc method by Sakai et al., and treatment efficacy was evaluated using the Visual Analog Scale, wherein patients gave subjective ratings for their symptoms (reductions by > 50% after administration of EL for 4 weeks were defined as improvements).

Results

Results showed that the improvement rates for patients with idiopathic and psychogenic taste disorders were 55 and 70%, respectively. Additionally, the majority (78%) improved within 2 weeks, and side effects were mild (seven cases with drowsiness and one case with dizziness).

Conclusions

We conclude that EL is an appropriate first-line medication for patients with idiopathic and psychogenic taste disorders.

A clinical survey on patients with taste disorders in Japan: A comparative study

OBJECTIVE

To investigate changes in the clinical state of taste disorders between 1990, 2003, and 2019 using the same methodology as that in previous studies.

MATERIALS AND METHODS

In June 2019, we mailed a questionnaire to 1100 otolaryngologists belonging to the Japan Society of Stomato-pharyngology and investigated three question categories: "Institution", "Number of patients for 3 months", and "Treatment". In addition, we analyzed some results by the class of institution.

RESULTS

The rate of patients who complained of taste disorders in the 2019 survey (220/100,000 persons/year) was twice that of the 1990 survey (110/100,000 persons/year), and slightly higher than that of the 2003 survey (192/100,000 persons/year). The rate of female patients was higher than that of male patients in all age groups. The number of patients was correlated with age up to 70 years of age in both genders. The rates of performing taste tests to assess taste function in the 2019 survey were significantly decreased compared with a 2003 survey (electrogustometry: p<0.001, filter paper disk method: p<0.05 in university). The rate of examination of the serum zinc in the 2019 survey was increased compared with the 1990 survey (p<0.001). Zinc oral therapy was used for the treatment of taste disorders in 239/299 (79.9%) patients/institutes for 3 months. In addition, 213 institutions (69.6%) answered that zinc oral therapy was efficacious for taste disorders.

CONCLUSION

The patients who complained of taste disorder have increased. The zinc administration is an appropriate clinical treatment for taste disorders in Japan. To enhance treatment for taste disorders, simpler methods for assessing taste function need to be developed, and the pathological mechanisms of taste disorders other than zinc deficiency need to be clarified.

Effect of Oral Care in a Patient with Depression and Burning Mouth Syndrome during the COVID-19 Pandemic

Burning mouth syndrome (BMS) is a burning sensation that occurs in the mouth without any underlying cause. There is no satisfactory treatment for BMS, so far. Herein, we report the case of a 74-year-old female with untreated depression who presented with BMS. Despite taking antidepressants, she developed suicidal thoughts, particularly due to the increasing number of coronavirus disease 2019 (COVID-19) cases and suicides in Japan. The symptoms of BMS and the oral discomfort were eliminated using a multifaceted approach, which included the following: continuous application of the oral care gel "REFRECARE-H®" to the mucous membranes, regular dental visits, collaboration with medical and dental professionals, and administration of zinc preparations. Her suicidal thoughts had disappeared, and her quality of life, assessed using the visual analogue scale, was improved following the treatment. Dentists should strive to provide oral care, while providing treatment in collaboration with specialists, for the early detection of depression and zinc deficiency in patients with BMS.

Assessment of Taste Function

Taste disorders, impacting well-being and physical health, can be caused by many etiologies including the use of medication. Recently, taste disturbance is also considered as one of the predominant symptoms of COVID-19 although its pathogenesis requires further research. Localized taste disorders may be overlooked considering that whole-mouth taste perception is insured through several mechanisms. Individuals often fail to discern taste from flavor, and interviews/surveys are insufficient to properly assess taste function. Hence, various taste assessment methods have been developed. Among them, psychophysical methods are most widely applied in a clinical context. Less-biased electrophysiological, imaging, or morphological methods are used to a much lesser degree. Overall, more research is needed in the field of taste.

Prognostic factors of recovery with medication in patients with taste disorders

Objectives

We aimed to elucidate the prognostic factors of the patients with taste disorders who were treated with popular and common medication in Japan.

Materials and methods

A retrospective study on the medical charts of a total of 255 patients with taste disorders who were treated primarily with oral medication including a zinc agent.

Results

The factors below were significantly linked with poor prognosis: 1) male gender, 2) taste disorders that began 3 months before starting treatment and 3) a severe taste disorder grade at the initial visit.

Conclusions

We have concluded that the prognosis for the patients with taste disorders who were treated by popular and standard medication therapy in Japan recently was significantly linked to gender, the period of 3 months before starting the treatment and the severity of the disorder at the time of diagnosis. In addition, we recognized some limitations we should resolve in further research including a method of measuring “umami” and so on.

Clinical relevance

Better awareness of these factors should be clinically useful when we manage patients with taste disorders. Earlier treatment should be started to cure the symptoms.

Evaluation of treatment with zinc acetate hydrate in patients with liver cirrhosis complicated by zinc deficiency

AIM

In Japan, no zinc preparation had been approved for therapeutic purposes before March 2017. Zinc acetate hydrate was recently approved for the treatment of hypozincemia. We evaluated the efficacy and safety of treatment with zinc acetate hydrate.

METHODS

A total of 97 patients with cirrhosis complicated by hypozincemia were treated with zinc acetate hydrate, and their serum zinc normalization rates; factors contributing to normalization; changes in blood ammonia levels; branched-chain amino acids-to-tyrosine ratios; levels of albumin, hemoglobin, alkaline phosphatase, serum copper, and iron; incidence of adverse events; improvement in subjective symptoms; and serum zinc levels taken at 3 months post-treatment were determined.

RESULTS

The cumulative serum zinc normalization rates, when normalization was defined as achievement of a serum zinc level ≥80 μg/dL, after 2, 4, and 6 months of treatment were 64.9%, 80.3%, and 82.5%, respectively. Multivariate analysis identified an albumin level of ≥3.3 g/dL and branched-chain amino acids to tyrosine ratio of ≥3.46 as factors contributing to zinc normalization within 3 months of treatment. Treatment resulted in a significant decrease in blood ammonia and serum copper levels, and significant increases in branched-chain amino acids-to-tyrosine ratios and alkaline phosphatase levels. Seven (7.2%) patients prematurely discontinued treatment due to hypocupremia. By the end of treatment, subjective symptoms had resolved in 46.2% of patients. By 3 months post-treatment, serum zinc levels had reverted to levels close to those at baseline.

CONCLUSIONS

Treatment with zinc acetate hydrate resulted in normalization of serum zinc levels at a high rate. The main reasons for discontinuation of treatment included hypocupremia.

Association between taste perception, nutrient intake, and mental health in young Japanese women

BACKGROUND/OBJECTIVES

Taste perception is influenced by both nutritional factors and psychological factors. This study was undertaken to measure the 4 basic taste perceptions, nutrient intake, and mental health, and to examine the factors that affect insensitive taste perception in young Japanese women.

SUBJECTS/METHODS

Young women in their late teens and twenties were enrolled as subjects. Taste perception was measured by applying the filter-paper disc method over areas of the chorda tympani nerve. Nutritional status was evaluated using brief, self-administered diet history questionnaires. The index of nutritional status was based on the 2015 Japanese dietary reference intakes. Mental health was assessed using the Japanese translation of the Profile of Mood States short version. This study was approved by the ethical committee at Osaka University.

RESULTS

The normal taste perception group (four basic tastes [sweet, salty, sour, and bitter] identified as normal taste perception) comprised 55.4% of the subjects, while the abnormal taste perception group (more than 1 abnormal taste perception was perceived, regardless of flavor) comprised 44.6% of the subjects. There were no significant differences in nutrient intake (except manganese) and mental health between the normal and abnormal taste perception groups. Subjects who took 5 mg to less than 7.1 mg zinc per day were at significantly decreased risk of insensitive taste perception compared to subjects who consumed less than 5 mg zinc per day [Regression coefficient 0.831, 95% confidence interval 0.694-0.996].

CONCLUSION

The present results suggest that insensitive taste perception could be associated with zinc deficiency in young women in their late teens and twenties.

Development of a Gustatory Function Test for Clinical Application in Korean Subjects

PURPOSE

To obtain validated clinical values suitable for developing a gustatory function test, including umami taste, in a Korean population.

MATERIALS AND METHODS

The investigation involved 297 participants with self-reported normal sense of taste and smell. Liquid solutions were used for the assessment of gustatory function. The test consisted of 30 taste solutions [six concentrations of five tastants (sweet, bitter, salty, sour, and umami)]. For evaluation of overall gustatory function, the number of detected or correctly recognized taste thresholds was combined to form a "taste score."

RESULTS

Mean values of each detection and recognition threshold for the five tastes in men were consistently lower than those of women. The 10th percentile of taste score for recognition was used as the cut-off value for distinguishing normogeusia from hypogeusia. In subgroup analysis, total taste score from recognition thresholds revealed a significant negative correlation with age, indicating lower scores for increasing age. Taste score for non-smokers was significantly higher than that of smokers, in terms of detection and recognition of taste sensitivities.

CONCLUSION

This gustatory function test was easy to perform, affordable, and time-saving, with the capacity to self-produce and obtain reliable data. Gustatory function was more sensitive in young people, women, and non-smokers.

Zinc, Carnosine, and Neurodegenerative Diseases

Zinc (Zn) is abundantly present in the brain, and accumulates in the synaptic vesicles. Synaptic Zn is released with neuronal excitation, and plays essential roles in learning and memory. Increasing evidence suggests that the disruption of Zn homeostasis is involved in various neurodegenerative diseases including Alzheimer's disease, a vascular type of dementia, and prion diseases. Our and other numerous studies suggest that carnosine (β-alanyl histidine) is protective against these neurodegenerative diseases. Carnosine is an endogenous dipeptide abundantly present in the skeletal muscles and in the brain, and has numerous beneficial effects such as antioxidant, metal chelating, anti-crosslinking, and anti-glycation activities. The complex of carnosine and Zn, termed polaprezinc, is widely used for Zn supplementation therapy and for the treatment of ulcers. Here, we review the link between Zn and these neurodegenerative diseases, and focus on the neuroprotective effects of carnosine. We also discuss the carnosine level in various foodstuffs and beneficial effects of dietary supplementation of carnosine.

Interventions for managing taste disturbances

BACKGROUND

The sense of taste is very much essential to the overall health of an individual. It is a necessary component to enjoy one's food, which in turn provides nutrition to an individual. Any disturbance in taste perception can hamper quality of life in such patients by influencing their appetite, body weight and psychological well-being. Taste disorders have been treated using different modalities of treatment and there is no consensus for the best intervention. Hence this Cochrane Review was undertaken. This is an update of the Cochrane Review first published in November 2014.

OBJECTIVES

To assess the effects of interventions for the management of patients with taste disturbances.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 4 July 2017); the Cochrane Central Register of Controlled Trials (CENTRAL; 2017 Issue 6) in the Cochrane Library (searched 4 July 2017); MEDLINE Ovid (1946 to 4 July 2017); Embase Ovid (1980 to 4 July 2017); CINAHL EBSCO (1937 to 4 July 2017); and AMED Ovid (1985 to 4 July 2017). The US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for trials. Abstracts from scientific meetings and conferences were searched on 25 September 2017. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing any pharmacological agent with a control intervention or any non-pharmacological agent with a control intervention. We also included cross-over trials in the review.

DATA COLLECTION AND ANALYSIS

Two pairs of review authors independently, and in duplicate, assessed the quality of trials and extracted data. Wherever possible, we contacted trial authors for additional information. We collected adverse events information from the trials.

MAIN RESULTS

We included 10 trials (581 participants), nine of which we were able to include in the quantitative analyses (566 participants). We assessed three trials (30%) as having a low risk of bias, four trials (40%) at high risk of bias and three trials (30%) as having an unclear risk of bias. We only included studies on taste disorders in this review that were either idiopathic, or resulting from zinc deficiency or chronic renal failure.Of these, nine trials with 544 people compared zinc supplements to placebo for patients with taste disorders. The participants in two trials were children and adolescents with respective mean ages of 10 and 11.2 years and the other seven trials had adult participants. Out of these nine, two trials assessed the patient-reported outcome for improvement in taste acuity using zinc supplements (risk ratio (RR) 1.40, 95% confidence interval (CI) 0.94 to 2.09; 119 participants, very low-quality evidence). We meta-analysed for taste acuity improvement using objective outcome (continuous data) in idiopathic and zinc-deficient taste disorder patients (standardised mean difference (SMD) 0.44, 95% CI 0.23 to 0.65; 366 participants, three trials, very low-quality evidence). We also analysed one cross-over trial separately using the first half of the results for taste detection (mean difference (MD) 2.50, 95% CI 0.93 to 4.07; 14 participants, very low-quality evidence), and taste recognition (MD 3.00, 95% CI 0.66 to 5.34; 14 participants, very low-quality evidence). We meta-analysed taste acuity improvement using objective outcome (dichotomous data) in idiopathic and zinc-deficient taste disorder patients (RR 1.42, 95% 1.09 to 1.84; 292 participants, two trials, very low-quality evidence). Out of the nine trials using zinc supplementation, four reported adverse events like eczema, nausea, abdominal pain, diarrhoea, constipation, decrease in blood iron, increase in blood alkaline phosphatase, and minor increase in blood triglycerides.One trial tested taste discrimination using acupuncture (MD 2.80, 95% CI -1.18 to 6.78; 37 participants, very low-quality evidence). No adverse events were reported in the acupuncture trial.None of the included trials could be included in the meta-analysis for health-related quality of life in taste disorder patients.

AUTHORS' CONCLUSIONS

We found very low-quality evidence that was insufficient to conclude on the role of zinc supplements to improve taste acuity reported by patients and very low-quality evidence that zinc supplements improve taste acuity in patients with zinc deficiency/idiopathic taste disorders. We did not find any evidence to conclude the role of zinc supplements for improving taste discrimination, or any evidence addressing health-related quality of life due to taste disorders.We found very low-quality evidence that is not sufficient to conclude on the role of acupuncture for improving taste discrimination in cases of idiopathic dysgeusia (distortion of taste) and hypogeusia (reduced ability to taste). We were unable to draw any conclusions regarding the superiority of zinc supplements or acupuncture as none of the trials compared these interventions.

Interventions for the management of taste disturbances

BACKGROUND

The sense of taste is very much essential to the overall health of the individual. It is a necessary component to enjoying one's food, which in turn provides nutrition to an individual. Any disturbance in taste perception can hamper the quality of life in such patients by influencing their appetite, body weight and psychological well-being. Taste disorders have been treated using different modalities of treatment and there is no consensus for the best intervention. Hence this Cochrane systematic review was undertaken.

OBJECTIVES

To assess the effects of interventions for the management of patients with taste disturbances.

SEARCH METHODS

We searched the Cochrane Oral Health Group Trials Register (to 5 March 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2014), MEDLINE via OVID (1948 to 5 March 2014), EMBASE via OVID (1980 to 5 March 2014), CINAHL via EBSCO (1980 to 5 March 2014) and AMED via OVID (1985 to 5 March 2014). We also searched the relevant clinical trial registries and conference proceedings from the International Association of Dental Research/American Association of Dental Research (to 5 March 2014), Association for Research in Otolaryngology (to 5 March 2014), the US National Institutes of Health Trials Register (to 5 March 2014), metaRegister of Controlled Trials (mRCT) (to 5 March 2014), World Health Organization's International Clinical Trials Registry Platform (WHO ICTRP) (to 5 March 2014) and International Federation of Pharmaceutical Manufacturers and Associations (IFPMA) Clinical Trials Portal (to 5 March 2014).

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing any pharmacological agent with a control intervention or any non-pharmacological agent with a control intervention. We also included cross-over trials in the review.

DATA COLLECTION AND ANALYSIS

Two authors independently, and in duplicate, assessed the quality of trials and extracted data. Wherever possible, we contacted study authors for additional information. We collected adverse events information from the trials.

MAIN RESULTS

We included nine trials (seven parallel and two cross-over RCTs) with 566 participants. We assessed three trials (33.3%) as having a low risk of bias, four trials (44.5%) at high risk of bias and two trials (22.2%) as having an unclear risk of bias. We only included studies on taste disorders in this review that were either idiopathic, or resulting from zinc deficiency or chronic renal failure.Of these, eight trials with 529 people compared zinc supplements to placebo for patients with taste disorders. The participants in two trials were children and adolescents with respective mean ages of 10 and 11.2 years and the other six trials had adult participants. Out of these eight, two trials assessed the patient reported outcome for improvement in taste acuity using zinc supplements (RR 1.45, 95% CI 1.0 to 2.1; very low quality evidence). We included three trials in the meta-analysis for overall taste improvement (effect size 0.44, 95% CI 0.23 to 0.65; moderate quality evidence). Two other trials described the results as taste acuity improvement and we conducted subgroup analyses due to clinical heterogeneity. One trial described the results as taste recognition improvement for each taste sensation and we analysed this separately. We also analysed one cross-over trial separately using the first half of the results. None of the zinc trials tested taste discrimination. Only one trial tested taste discrimination using acupuncture (effect size 2.80, 95% CI -1.18 to 6.78; low quality evidence).Out of the eight trials using zinc supplementation, four reported adverse events like eczema, nausea, abdominal pain, diarrhoea, constipation, decrease in blood iron, increase in blood alkaline phosphatase, and minor increase in blood triglycerides. No adverse events were reported in the acupuncture trial.None of the included trials could be included in the meta-analysis for health-related quality of life in taste disorder patients.

AUTHORS' CONCLUSIONS

We found very low quality evidence that was insufficient to conclude on the role of zinc supplements to improve taste perception by patients, however we found moderate quality evidence that zinc supplements improve overall taste improvement in patients with zinc deficiency/idiopathic taste disorders. We also found low quality evidence that zinc supplements improve taste acuity in zinc deficient/idiopathic taste disorders and very low quality evidence for taste recognition improvement in children with taste disorders secondary to chronic renal failure. We did not find any evidence to conclude the role of zinc supplements for improving taste discrimination, or any evidence addressing health-related quality of life due to taste disorders.We found low quality evidence that is not sufficient to conclude on the role of acupuncture for improving taste discrimination in cases of idiopathic dysgeusia (distortion of taste) and hypogeusia (reduced ability to taste). We were unable to draw any conclusions regarding the superiority of zinc supplements or acupuncture as none of the trials compared these interventions.

[Time course of changes in gustatory function test results and subjective symptoms, and predictive factors for response in patients with taste disorder receiving 24-week zinc replacement treatment]

In a taste disorder, an agreement between patients' complaints and gustatory function test results is not necessarily found both at the initial hospital visit and during the course of treatment; therefore, it is difficult to assess treatment responses and review treatment strategies based on the assessed treatment responses. The present study investigated the time course of changes in disc gustometry results and subjective symptom scores measured at 4-week intervals in 44 patients with a taste disorder who were considered eligible for zinc replacement treatment and who received polaprezinc at a dose of 150 mg/day (equivalent to a 34 mg/day dose of zinc) for up to 24 weeks. The study also examined the potential differences in treatment outcomes according to the predictive factors for response such as patient background and assessed disc gustometry results during the course of treatment. Results indicated that disc gustometry results and subjective symptom scores showed different time courses of changes. The response rate as measured by disc gustometry was 47.7% at week 12 of treatment, and showed a subsequent slow increase to 56.8% at week 24. On the other hand, subjective symptom scores showed a time-proportional improvement up to week 24. Among the patients included in the present study, a clear difference was found according to the presence or absence of an improving trend as determined by disc gustometry at week 12 of treatment, although there were no differences in ultimate treatment responses, including categories of taste disorder, according to patient background. Patients showing a trend toward improvement had significantly better treatment responses in terms of both ultimate response rates and subjective symptom scores, whereas patients showing no trend toward improvement were less likely to respond to the subsequent 12-week continued treatment.

Taste hyposensitivity in Japanese schoolchildren

Background

There is some research on taste disorder/hyposensitivity in special groups such as the elderly or patients presenting with specific taste problems, however few studies have been conducted among young populations. The objectives of this study were to estimate the prevalence of taste hyposensitivity and to investigate the relationship between taste hyposensitivity and oral health status in Japanese schoolchildren.

Methods

Subjects were 237 primary and 112 junior high school students in Saitama Prefecture, Japan. In total, 349 (boys: 181, girls: 168) students aged 6–15 years participated in the study. Oral examinations and whole-mouth taste tests using four tastes (sweet, salt, sour and bitter) solutions were conducted on the subjects. A subject who could not recognize the taste of the solution was defined as demonstrating hyposensitivity.

Results

Hyposensitivity was observed in 6.3% of all subjects for sweet-taste, 14.3% for salt-taste, 20.9% for sour-taste and 6.0% for bitter-taste. The prevalence of sweet, sour and bitter-taste hyposensitivity decreased as the subjects’ grade advanced. In contrast, the prevalence of salt-taste hyposensitivity increased in 7^th-9^th grade subjects. Furthermore, the prevalence of bitter-taste hyposensitivity was significantly higher in males than females among 1^st-3^rd graders.

Taste hyposensitivity had little association with oral health status, such as decayed teeth, filled teeth, dental plaque, gingival status and tongue coating.

Conclusions

In this study, taste hyposensitivity was observed in 6.0%-20.9% of the students. There was little association between taste hyposensitivity and oral health status. The current study implies that the factors affecting the taste hyposensitivity in children may different from those in the elderly. Therefore it is necessary to further investigate the causes of taste hyposensitivity among younger generation.

[The effect of zinc agent in 219 patients with zinc deficiency-inductive/ idiopathic taste disorder: a placebo controlled randomized study]

Diagnosis and treatment of taste disorders are challenging because the disorder can only be determined by the awareness of the patient. Hence, these disorders still require comprehensive evidence. We conducted a randomized, placebo-controlled double-blind study to investigate the effect of polaprezinc, a zinc-containing agent, in 219 patients with either zinc deficiency-inductive or an idiopathic taste, disorder. As a result, the zinc-treated arm experienced a statistically significant improvement against the placebo-treated arm in the perceptible threshold scores of the filter-paper disk method 8 weeks after the administration of the investigational drug. Moreover, the effect lasted for 4 weeks after discontinuation of the drug. However, the effective ratios based on the initial criteria were 55.6% in the treatment group and 43.2% in the placebo, where no statistical significance was recorded. Sex and degree of depression could be two of the potential factors to explain this discrepancy. Furthermore, the effect was not significant among male patients and patients with a high depression score based on the Self-rating Depression Scale (SDS) test. These results indicate that determining the symptom among such patients remains undisclosed. Whereas, in approximately 77%, or 168 patients with "normal" SDS scores and with completely impaired taste qualities, the ratio of effective cases reached 60.9% in the zinc-treated group, the ratio of the placebo-treated group reached 39.5%, resulting in a statistical significance. This may be partly because of a problem in the adaption of male subjects to the gustatory analyses, especially to the identification of saltiness and sourness. Care must also be taken regarding the depressive state of patients when diagnosing and treating taste disorders. Taste disorders caused by depression may not be cured by zinc supplementation due in part to the fact that the symptom is based on a mental issue, and due in part to the conservative responding bias generated by the depression itself, which may inhibit accurate and precise diagnosis of the disorder. In conclusion, administration of a zinc agent is effective for patients with taste disorders, provided selection of appropriate patients is performed, and that proper examination and evaluation are conducted. The present study also indicated that examining depressiveness based on the SDS scores and investigating disturbance of each taste quality using the filter-paper disk method are recommended for the diagnosis and determination of the treatment effect of a taste disorder.

Oral complications of cancer and cancer therapy: from cancer treatment to survivorship

Answer questions and earn CME/CNE Oral complications resulting from cancer and cancer therapies cause acute and late toxicities that may be underreported, underrecognized, and undertreated. Recent advances in cancer treatment have led to changes in the incidence, nature, and severity of oral complications. As the number of survivors increases, it is becoming increasingly recognized that the aggressive management of oral toxicities is needed to ensure optimal long-term oral health and general well-being. Advances in care have had an impact on previously recognized oral complications and are leading to newly recognized adverse effects. Here, the authors briefly review advances in cancer therapy, including recent advances in surgery, oral care, radiation therapy, hematopoietic cell transplantation, and medical oncology; describe how these advances affect oral health; and discuss the frequent and/or severe oral health complications associated with cancer and cancer treatment and their effect upon long-term health. Although some of the acute oral toxicities of cancer therapies may be reduced, they remain essentially unavoidable. The significant impact of long-term complications requires increased awareness and recognition to promote prevention and appropriate intervention. It is therefore important for the primary oncologist to be aware of these complications so that appropriate measures can be implemented in a timely manner. Prevention and management is best provided via multidisciplinary health care teams, which must be integrated and communicate effectively in order to provide the best patient care in a coordinated manner at the appropriate time.

Effects of dietary zinc deprivation on zinc concentration and ratio of apo/holo-activities of angiotensin converting enzyme in serum of mice

OBJECTIVE

The aim of the present study was to evaluate the effects of dietary zinc deprivation on zinc concentration, the activity of angiotensin converting enzyme (ACE) and ratio of apo/holo-activities of ACE (ACE ratio) in the serum of mice.

METHODS

Twenty-two male mice were deprived of dietary zinc for up to 9 days. Zinc concentration in the serum was measured by means of atomic absorption spectrometry. Also, the activity of ACE in the serum was measured by HPLC as the activity of holo-ACE. After addition of zinc to the serum in vitro, the increase of ACE activity over the initial value was determined as that of apo-ACE. Finally, the ratio of apo/holo-ACE activities was calculated.

RESULTS

There was a significant decrease of zinc concentration, but a slight decrease of the activity of ACE in the serum of mice by intake of zinc-deficient diet for 9 days. ACE ratio tended to increase on day 5 and was significantly increased on day 9 in mice deprived of dietary zinc.

CONCLUSION

These findings suggest that ACE ratio is as sensitive as serum zinc concentration for the evaluation of zinc deficiency and can be used for the biochemical diagnosis of zinc nutritional status in patients with zinc deficiency-induced taste impairment.

Exploring taste hyposensitivity in Japanese senior high school students

AIM

The main objective of this study was to investigate the prevalence of taste hyposensitivity and the relationships between sex, oral health status, and eating habits with taste hyposensitivity in Japanese senior high school students.

METHODS

Oral examinations, sweet and salt whole-mouth taste tests, and a questionnaire about eating habits were conducted on 234 senior high school students. Factors affecting taste hyposensitivity were investigated using a multivariate analysis.

RESULTS

Sweet-taste hyposensitivity was observed in 7.3% of the students, and salt-taste hyposensitivity in 22.2%. Approximately 3% of the students had both sweet- and salt-taste hyposensitivity, and 22.6% had either sweet- or salt-taste hyposensitivity. In total, 26% had a taste hyposensitivity. There were significant relationships between the intake of instant noodles with sweet-taste hyposensitivity, and the intake of vegetables or isotonic drinks with salt-taste hyposensitivity.

CONCLUSIONS

There was a significant association between eating habits and taste hyposensitivity in Japanese senior high school students. Taste tests would be a helpful adjunct for students to recognize variations in taste sensitivity, and a questionnaire about their eating habits might provide an effective self-review of their eating habits, and therefore, provide motivation to change.

Evaluation of electrogustometry and the filter paper disc method for taste assessment

CONCLUSION

The results indicate that electrogustometry and the filter paper disc method are reliable methods to measure taste with a high degree of reproducibility.

OBJECTIVES

To thoroughly evaluate the reliability of electrogustometry and the filter paper disc method for taste assessments.

METHODS

Thirty-nine healthy test persons without any history of chronic middle ear disease, aged between 27 and 62 years, were recruited. In all, 772 electrogustometry and 30 filter paper disc assessments were made. A nerve decay test was performed, with measures taken before and after eating sweet, sour, bitter, salt, a mild or spicy meal, after smoking, and after taking Swedish tobacco snuff ('snus'), as well as before and after local anesthesia of the tongue. Measurements were performed on 5 consecutive days and repeatedly during 1 day. The correlation between electrogustometry and the filter paper disc method was also studied.

RESULTS

The results indicate that electrogustometry and the filter paper disc method are reliable methods to measure taste with a high degree of reproducibility. The only actions causing significant changes in the electrogustometry readings were eating a bitter substance and having local anesthesia of the tongue. The correlation between the methods was statistically significant except for the bitter flavor, where the correlation was just below the level of significance.

A zinc-containing compound, Polaprezinc, is effective for patients with taste disorders: randomized, double-blind, placebo-controlled, multi-center study

CONCLUSIONS

The effect of a zinc-containing compound, Polaprezinc, was shown to clinically improve the disease conditions of idiopathic taste disorders with no serious side effects in a well controlled double-blinded clinical study.

OBJECTIVES

The purpose of the present study was to evaluate the efficacy and safety of a zinc-containing compound in the treatment of patients with idiopathic taste disorders, including patients with low serum zinc, by a Good Clinical Practice (GCP)-compliant, randomized, placebo-controlled, double-blind, multi-center clinical study.

SUBJECTS AND METHODS

A group of 109 patients suffering from taste disorders was assigned into placebo and three treatment groups. Each group of patients was given either placebo (n=28), or 17 mg (n=27), 34 mg (n=26) or 68 mg (n=28) of oral zinc, Polaprezinc preparations, daily for 12 weeks.

RESULTS

The group of patients given 68 mg zinc showed a significant improvement in their gustatory sensitivity compared with the placebo group. The most common side effects observed were increase in serum triglyceride and serum alkaline phosphatase, decrease in serum iron, and some gastrointestinal incidents, although they were not serious.

Effects of zinc supplementation on serum zinc concentration and ratio of apo/holo-activities of angiotensin converting enzyme in patients with taste impairment

OBJECTIVE

The aim of the present study was to evaluate the effects of zinc supplementation on hypogeusia, serum zinc concentration and the ratio of apo/holo-activities of angiotensin converting enzyme (ACE ratio) in patients with taste impairment. ACE ratio was used as an index of zinc nutritional status.

METHODS

Forty patients complaining of taste impairment were divided into two groups: zinc deficiency taste impairment (n=12) and idiopathic taste impairment (n=28). Patients with zincemia values of less than 63 microg/dl with no history of other disorder or medication known to cause dysgeusia were diagnosed as zinc deficiency group, while those with the same condition and values more than 64 microg/dl were considered to belong to the idiopathic group. Patients orally received 150 mg of polaprezinc containing 33 mg of zinc every day. Subjective symptom was scored according to visual analogue scale (VAS).

RESULTS

Zinc supplementation improved hypogeusia in both idiopathic and zinc deficiency groups. The mean improvements of VAS were 3.02+/-3.03 in the idiopathic group and 3.13+/-2.53 in the zinc deficiency group. Thus, there were no significant differences in idiopathic and zinc deficiency groups. Significant correlations were found between the improvement of VAS score and the ACE ratio after zinc supplementation in both idiopathic and zinc deficiency groups. On the contrary, significant correlations were not found between the improvement of VAS score and the zinc concentration in the serum after zinc supplementation in both groups.

CONCLUSION

The results of the present study indicated that zinc deficiency is a predominant factor underlying taste impairment and ACE ratio may be a predictor of the prognosis for taste impairment after zinc supplementation, in addition to a more sensitive indicator of zinc nutrition than zinc concentration in the serum.

[Clinical analysis of hyposmia-associated taste dysfunction]

We clarified the clinical features of "flavor dysfunction," defined as olfactory dysfunction with self-reported hypogeusia but normal taste function in gustatory tests compared to those of "smell and taste dysfunction" hyposmia and hypogeusia in olfactory and gustatory tests. Patients with flavor dysfunction reported significantly milder taste loss than those with other smell and taste dysfunction. The major smell and taste loss etiology was upper respiratory tract infection (URI) in the flavor dysfunction group and the URI rate was significantly higher in the flavor dysfunction group than in the smell and taste dysfunction group. Smell identification thresholds in T & T olfactometry were not different between groups. Flavor dysfunction, hyposmia was treated medically but not with conventional hypogeusia medication. Medication including zinc was administered for other smell and taste dysfunction. Both groups significantly recovered from taste dysfunction. Our results indicate that treating olfactory dysfunction effectively improves flavor dysfunction but hypogeusia need not necessarily be treated. Hyposmia and hypogeusia must be treated together for other smell and taste dysfunction, making it vital that we conduct appropriate gustatory testing to correctly differentiate between flavor and other smell and taste dysfunctions.

Carnosine and its possible roles in nutrition and health

The dipeptide carnosine has been observed to exert antiaging activity at cellular and whole animal levels. This review discusses the possible mechanisms by which carnosine may exert antiaging action and considers whether the dipeptide could be beneficial to humans. Carnosine's possible biological activities include scavenger of reactive oxygen species (ROS) and reactive nitrogen species (RNS), chelator of zinc and copper ions, and antiglycating and anticross-linking activities. Carnosine's ability to react with deleterious aldehydes such as malondialdehyde, methylglyoxal, hydroxynonenal, and acetaldehyde may also contribute to its protective functions. Physiologically carnosine may help to suppress some secondary complications of diabetes, and the deleterious consequences of ischemic-reperfusion injury, most likely due to antioxidation and carbonyl-scavenging functions. Other, and much more speculative, possible functions of carnosine considered include transglutaminase inhibition, stimulation of proteolysis mediated via effects on proteasome activity or induction of protease and stress-protein gene expression, upregulation of corticosteroid synthesis, stimulation of protein repair, and effects on ADP-ribose metabolism associated with sirtuin and poly-ADP-ribose polymerase (PARP) activities. Evidence for carnosine's possible protective action against secondary diabetic complications, neurodegeneration, cancer, and other age-related pathologies is briefly discussed.

Nizatidine enhances salivary secretion in patients with dry mouth

OBJECTIVE

It was reported that salivary secretion increased in 30 volunteers with administered nizatidine. The aim of the present study was to investigate whether or not nizatidine enhances salivary secretion and improves the function of salivary glands in patients with dry mouth.

METHODS

Both basal and stimulated salivary secretions were measured before and after the administration of nizatidine for a month in 18 healthy adult volunteers and 38 patients with dry mouth. In 6/38 patients, salivary gland scintigraphy was performed.

RESULTS

After the administration of nizatidine for a month, salivary secretions significantly increased in the control and dry mouth patient groups compared to the pretreatment baseline. In addition, 25 of 38 dry mouth patients showed subjective improvements of oral dryness. In 3/4 patients, the function of salivary glands was improved on salivary gland scintigraphy.

CONCLUSION

Nizatidine may reactivate salivary gland cells and be useful in the treatment of patients with dry month.

Is electrogustometry useful for screening abnormalities of taste?

Background:

Electrogustometry is an accurate and increasingly popular method used to examine taste. However, its usefulness as a screening test is unknown.

Methods:

We asked 114 subjects, some healthy but most with medical conditions possibly affecting taste, to rate their overall taste ability, on a scale of zero to 10. Those who had current symptoms related to taste– and who rated their taste as five or worse – were defined as ‘aberrant tasters’. We recorded automated electrogustometry thresholds, and visual analogue scale intensity ratings, for solutions of the four basic tastes (sweet, sour, salty and bitter). A visual analogue scale score of 50 was used as a cut-off point to identify ‘poor tasters’.

Results:

The sensitivity and specificity of electrogustometry in identifying abnormal taste function were low.

Conclusions:

We conclude that automated electrogustometry is not a useful clinical screening method for taste disturbance in a population such as ours.

Zinc nutrition in healthy subjects and patients with taste impairment from the view point of zinc ingestion, serum zinc concentration and angiotensin converting enzyme activity

OBJECTIVE

To estimate the zinc nutrition in healthy subjects and patients with taste impairment. Dietary zinc intake, zinc concentration in the serum and the ratio of apo/holo-activities of angiotensin converting enzyme (ACE), a zinc dependent enzyme in the serum (ACE ratio) were used as indices.

SUBJECTS

Healthy paramedical volunteers from a local hospital and patients with taste impairment seen in the Department of Otolaryngology, Tokushima University Hospital.

MEASUREMENTS

Dietary zinc intake was estimated with the food frequency questionnaire (FFQ). Zinc concentration in the serum was measured by means of atomic absorption spectrometry. The ACE activity in the serum was measured spectrophotometrically as the activity of holo-ACE, which contains zinc and shows full ACE activity. The activity of apo-ACE, which dose not contain zinc, was determined as the increase of its activity over that of the initial holo-ACE activity after the addition of zinc to the serum in vitro. ACE ratio was used as a more sensitive indicator of zinc nutrition than measuring zinc concentration in the serum.

RESULTS

There were no differences in dietary intake of zinc after adjusting for energy and zinc concentration in the serum between patients and age-adjusted healthy subjects. The ACE ratio in patients with taste impairment was significantly higher than that in age-adjusted healthy subjects (P<0.05).

CONCLUSION

Our date demonstrate that zinc deficiency is a predominant factor underlying taste impairment and we hypothesize that patients with taste impairment may have malabsorption of dietary zinc.