Therapeutic supplementation with zinc in the management of COVID-19-related diarrhea and ageusia/dysgeusia: mechanisms and clues for a personalized dosage regimen.

Zinc supplementation is indicated for diarrhea and taste disorders, which are both features of COVID-19 . Nevertheless, this strategy has not been tested for the treatment of these secondary complications in the current pandemic. Through an updated review, a practical appraisal was considered as a means of providing a medical nexus of therapeutic zinc regimens as an adjunct in the management of COVID-19-related diarrhea and ageusia/dysgeusia. While diarrhea and taste disorders are consequences of COVID-19, zinc supplementation is useful for non-COVID-19 patients with these clinical problems. The overwhelming evidence for supplementing with zinc in diarrhea and pneumonia is associated with the treatment of children, while for taste disorders the use of supplementing with zinc is more examined in adults. Whereas COVID-19 is more prevalent in adults, precautions should be exercised not to translate the zinc dosage used for children with diarrhea and taste disorders into the current pandemic. Therapeutic doses of zinc used for adults (∼50-150 mg/day of elemental zinc) could be included in the treatment strategies for COVID-19, but this proposal should be examined through randomized studies.

Taste and smell disturbances in cancer patients: a scoping review of available treatments.

PURPOSE: Taste and smell disturbances in patients affected by cancer are very common, but often under-recognized symptoms. If not addressed properly, they may impact nutritional status, food enjoyment, and quality of life. Treatment tools available for clinicians to manage chemosensory alterations are limited and are often based on personal clinical experiences. The aim of this study was to assess current oncological and palliative care literature through a scoping review, in order to identify available treatments for taste and smell alterations in cancer patients. METHODS: Medline, Embase, CINAHL, ProQuest Dissertations and Theses, and Google Scholar were searched from inception until January 2020, with subject headings relevant to the domains of chemosensory alterations, palliative, and cancer care. A total of 10,718 English and French language publications were reviewed, yielding 43 articles on the researched topic. RESULTS: The heterogeneity of selected articles led to difficulties in interpretation and analysis of the available evidence. Included publications differed in study design, population sample, anticancer treatments, and measures of assessment for taste and smell disturbances. A broad variety of treatment options were described including zinc and polaprezinc, radio-protectors, vitamins and supplements, anti-xerostomia agents, active swallowing exercises, nutritional interventions, delta-9-tetrahydrocannabinol, and photobiomodulation. CONCLUSION: This scoping review identifies the current state of knowledge regarding chemosensory alterations within supportive cancer care. Despite not reaching firm conclusions, this article offers therapeutic venues to further explore in larger and more methodologically sound studies.

Effect of Zinc Acetate Dihydrate (NobelzinR) Treatment on Anemia and Taste Disorders in Patients with Chronic Kidney Disease with Hypozincemia.

Some patients with chronic kidney disease (CKD) receiving hemodialysis develop erythropoietin-resistant anemia, possibly due to zinc deficiency. The frequency of zinc deficiency in CKD (stages 1-5 and 5D) and CKD improvement via zinc supplementation are not completely verified. Here 500 CKD patients (Stage 1/2, n=100; Stage 3, n=100; Stage 4, n=100, Stage n=5, 100; Stage 5D, n=100) will be recruited to determine the frequency of serum zinc deficiency at each CKD stage. Patients with serum zinc concentrations <80 µg/dL will be treated with zinc acetate dihydrate (NobelzinR) to evaluate its effects on hypozincemia, taste disturbances, and anemia.

[The role of zinc in chronic kidney disease].

Renal anemia is one of the most important complication as a cause of cardiovascular event in patients with chronic kidney disease (CKD). The status of renal anemia has been ameliorated by using recombinant human erythropoietin (EPO), however, the EPO resistant anemia is sometimes seen in high stage CKD patients. Heavy metal deficiency including zinc deficiency is one of the cause of EPO resistant anemia. Recently, it is reported that zinc deficiency is seen in patients with CKD. In this article, we describe zinc deficiency in patients with CKD. The ability that zinc supplementation improves their anemia in CKD patients is also described.

Zinc and Taste Disturbances in Older Adults: A Review of the Literature.

According to the National Health and Nutrition Examination Survey III, 35% to 45% of adults 60 years of age or older had zinc intakes below the estimated average requirement of 6.8 mg/day for elderly females and 9.4 mg/day for elderly males. Zinc deficiency may lead to loss of appetite, impaired immune function, weight loss, delayed healing of wounds, eye and skin lesions, and smell and taste disturbances. Older adults are especially affected by changes in taste sensations because of age-related gustatory dysfunction, use of multiple medications, increased frailty, and zinc deficiency. This article reviews the finding of clinical studies investigating the use of zinc supplementation for improvement with taste disturbances in older adults.

[Clinical analysis of 1059 patients with taste disorders].

Taste disorders are caused by several factors, and there have been few reports concerning the clinical course of taste disorders. In this study, patients with taste disorders were classified into 10 groups according to causes, and they were retrospectively studied in terms of therapeutic effects. In total, 1059 patients (412 men and 647 women, mean age: 60.0 years) who complained of taste disorders were reviewed in our clinic. The patients were asked detailed questions about their history of symptoms, and their emotional status was assessed using a self-rating depression scale. In all subjects, taste functions were measured by electrogustometry (EGM) and filter paper disks (FPD). The grades of their symptoms were assessed with a visual analogue scale (VAS). In addition, the levels of serum iron, copper, and zinc were examined. The patients were treated with zinc sulfate, polaprezinc, iron preparation, herbal medicine, and minor tranquilizers according to the factors causing the taste disorders. The most frequent cause was idiopathic taste disorder (192 cases, 18.2%), the second was psychogenic (186 cases, 17.6%), and the third was drug-induced (179 cases, 16.9%). The recovery rate of the symptoms was 64/92 (70.2%) in post-common cold, 31/35 (88.6%) in iron deficiency, and 85/116 (73.3%) in zinc deficiency. In these groups, the rates of recoveries were better than in the other groups. The recovery period in drug-induced taste disorders was approximately twice as long as the recovery period in the other groups. In the patients who were able to start treatment within 6 months from the onset of taste disorder, the recovery rate was significantly higher and the therapeutic period was significantly shorter than in those who had the disorders for more than 6 months (p<0.05, respectively).

[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.

The role of zinc in the treatment of taste disorders.

In the 1990s the number of patients diagnosed with taste disorders in the USA and Japan was over one million people each year, and the number is increasing annually. Taste disorders are caused by several factors such as genetic disease, head trauma, structural changes, glossodynia, cancer, change of lifestyle, and more. The role of zinc in the treatment of taste disorders has been studied since the oral administration of zinc by patients was reported to improve their taste disorders. Carbonic anhydrase (CA), a zinc metalloenzyme, has also been studied in association with taste disorders, since the regulation of serum CA levels was shown to influence the effect of orally administrated zinc in the treatment of taste disorders. Zinc is an essential trace element that contributes to the active center of approximately 300 enzymes. Studies have revealed that zinc is involved in various physiological functions. Moreover, some medications have been shown to induce a zinc deficiency, which has been associated with a variety of clinical conditions. Hence, since the relationship between taste disorder and serum zinc concentration has been discussed for long time, taste disorder may be useful in diagnosing zinc deficiency. Moreover, it appears that medicines of the zinc-containing supplement type contribute to the treatment of taste disorders caused by zinc deficiency. Orally administered zinc has been shown to directly stimulate food intake via neuropeptide in the hypothalamus. Therefore, zinc administration may potentially be used to treat taste disorders, as well as several other diseases by stimulating feeding. The article presents some promising patents on the role of zinc in the treatment of taste disorders.

Loss of taste responds to high-dose biotin treatment.

BACKGROUND AND OBJECTIVE: We saw 2 patients who lost their sense of taste, which was restored by pharmacologic doses of biotin. The key objective is to describe the 2 case reports and suggest a potential treatment for unexplained loss of taste. METHODS AND DESIGN: The first patient was a 67-year-old woman who lost her sense of taste taking Juvenon, a dietary herbal supplement containing acyl-L-carnitine, lipoic acid, calcium, phosphorus, and biotin 300 µg per day. The second patient was a 60-year-old man who lost his sense of taste after a sleeve gastrectomy for obesity. RESULTS: The first patient did not respond to 5 mg per day of biotin, but taste was restored with 10 mg of biotin per day. Biotin was prescribed based on information that lipoic acid bound to the biotin transporter. Baseline urine gave no evidence of a pre-existing biotin deficiency. The second patient did not have restoration of taste after taking biotin 5 mg per day for 7 weeks but did have taste restoration on biotin 20 mg per day. Neither subject had an abnormal biotinidase level. CONCLUSIONS: Further research into the relationship of biotin to taste is clearly indicated. Loss of taste was very distressing and significantly altered the quality of life for both patients. Since biotin up to 40 mg per day has been shown to be safe, a therapeutic trial of pharmacologic doses of biotin should be considered as a potentially curative treatment in patients who present with a loss of taste that has no obvious cause.

Aminofeel improves the sensitivity to taste in patients with HCV-infected liver disease.

BACKGROUND: Patients with chronic liver diseases have a taste disorder and altered zinc metabolism. We investigated the effects of a supplement enriched with branched-chain amino acids (BCAA) (Aminofeel) on sensitivity to different tastes in patients with hepatitis C virus (HCV) infected liver disease. MATERIAL/METHODS: Nine patients (mean age 63.3+/-9.1 years) with HCV-related liver diseases were identified and examined for sensitivity to different tastes. Eight patients had no awareness of taste disorders, and 3 patients had oral lichen planus. We examined 4 tastes (sweet, salty, sour, and bitter) using a Taste Disk and sensitivity to different tastes was rated on a 6-point scale (I, II, III, IV, V, and VI). Each patient was given one sachet of Aminofeel after breakfast and another at bedtime for 90 days. RESULTS: Only one patient was aware of a taste disorder before administration of Aminofeel, but 4 patients had decreased gustatory sensitivity in the sour taste test, and 2 had it in the bitter taste test. Sensitivity to sour tastes significantly increased after the administration of Aminofeel(R) (P=0.03). Sensitivity to sweet tastes increased after the administration of Aminofeel (P=0.06). Zinc value significantly increased after the administration of Aminofeel (P=0.02). CONCLUSIONS: Patients with HCV-infected liver disease have decreased sensitivity to different tastes and decreased zinc levels. Some patients were unaware that they had a taste disorder. Aminofeel improved sensitivity to different tastes and increased zinc values. Thus, Aminofeel is a useful therapeutic agent for taste disorders.

Evaluation of efficacy of estrogen and phytotherapy in oral cavity alterations of women in menopause.

AIM: Hypo-estrogenism during menopause is the cause of numerous disturbances affecting various structures such as the oral cavity which can present with the following symptoms: changes in salivary secretion, gingivitis, bleeding and altered taste sensation. The object is to study whether hormone replacement therapy prescribed for female patients in menopause have any beneficial effect on the oral discomfort which affects the quality of life of these patients. METHODS: The study enrolled 95 female patients; 14 were the control group and received no hormone replacement therapy while 81 patients underwent two types of therapy: 38 were prescribed estrogen therapy and 43 phytotherapy. The main outcome measures were alterations of the oral cavity: salivary change, gingivitis, bleeding and taste changes. RESULTS: It was observed that the patients receiving treatment had an improvement or disappearance of symptoms in the oral cavity and that estrogen was more effective than phytotherapy regarding the salivary change while the gingivitis, bleeding and taste changes was the same for both therapies. CONCLUSIONS: Estrogen and phytotherapy have beneficial effect on oral discomfort in women in menopause. The proposed treatment can have a beneficial effect on osteopenia and osteoporosis and therefore also on possible increase of future tooth loss during menopause.

Neurological causes of taste disorders.

In caring for patients with taste disorders, the clinical assessment should include complete examination of the cranial nerves and, in particular, gustatory testing. Neurophysiological methods such as blink reflex and masseter reflex allow the testing of trigeminofacial and trigeminotrigeminal pathways. Modern imaging methods (MRI and computed tomography) enable the delineation of the neuroanatomical structures which are involved in taste and their relation to the bony skull base. From a neurological point of view, gustatory disorders can result from damage at any location of the neural gustatory pathway from the taste buds via the peripheral (facial, glossopharyngeal and vagal nerve) and central nervous system (brainstem, thalamus) to its representation within the cerebral cortex. Etiopathogenetically, a large number of causes has to be considered, e.g. drugs and physical agents, cerebrovascular disorders including dissection of the carotid artery and pontine/thalamic lesions, space-occupying processes - in particular tumors compressing the cerebellopontine angle and the jugular foramen of the skull base - head trauma and skull base fractures, isolated cranial mononeuropathy (e.g. Bell's palsy) or polyneuropathy, epilepsy, dementia, multiple sclerosis and major depression. In addition to this, aging can also lead to diminished taste perception. Due to the broad differential diagnostic considerations, it is essential to look for additional, even mild, neurological signs and symptoms. Treatment must relate to the underlying cause. Zinc may be tried in idiopathic dysgeusia.

[Clinical experiences of the medication to taste disturbance by serum trace deficiency, especially serum iron deficiency].

Serum zinc deficiency is known to be a major cause of taste disturbances, but the effects of serum iron deficiency on taste disturbances are not widely known. In the present study, we clinically investigated the relationship between taste disturbances and serum iron deficiency as well as the results of pharmacological therapy. The clinical and serological test results of 25 patients with serum iron deficiency (3 men and 22 women; mean age +/- SD, 56.1 +/- 16.5 years) were reviewed at the Department of Otolaryngology, Hospital of Hyogo College of Medicine. All of the patients had been seen at the hospital between January 1999 and February 2003. Electrogustometry (EGM) and the filter paper disc method (FPD) were used to measure taste function. The patients were treated with iron and zinc supplements. The age distribution of the patients peaked at the ages of 40 and 70 years. The ratio of males to females was 1:7. Based on the EGM results, 70% of the patients exhibited taste disturbances. The FPD results showed that the recognition threshold of sour tastes was slightly higher than that of the other tastes. No significant difference in the results of treatment was seen, regardless of the duration of the deficiency. These results suggest that treatment with iron and zinc medicine is useful for correcting taste disturbances caused by serum deficiencies of trace elements.

Influence of early high-dose steroid treatment on Bell's palsy evolution.

The objective of this double-blind, randomized, placebo-controlled study was to test the efficacy of high-dose prednisone, administered as early as possible, in modifying the natural progression of Bell's palsy. Sixty-two consecutive patients, enrolled within 72 hours of facial palsy onset, were assigned to high dose intravenous prednisone in combination with intramuscular polyvitaminic therapy (group A) or polyvitaminic therapy alone (group B). Clinical grading of facial muscle strength and length of absence from work were evaluated. An early worsening of facial muscle strength was observed in controls, leading to the divergence in the trends of the grading scores in the two groups; this result was not confirmed in the long-term follow-up. Treated patients returned to work earlier than controls. In conclusion, early treatment based on high-dose corticosteroids slightly accelerates spontaneous improvement in Bell's palsy.

Taste disturbance in two patients after dental anesthesia by inferior alveolar nerve block.

We report two cases of temporary taste disturbance after inferior alveolar nerve block. The first patient to present with this rare complication of anesthesia for dental surgery was a 41-year-old woman. She lost the sense of taste on the left side of her tongue after local anesthesia for treatment of a left mandibular molar and first visited our outpatient clinic complaining of taste disorder 3 months later. Electrogustometry (EGM) and filter paper disk (FPD) testing revealed a taste disturbance in the innervation area of the left chorda tympani nerve and atrophy of the fungiform papillae on the left side of the tongue was observed. Eleven months after the dental treatment, the fungiform papillae and the results of EGM were normal. The second patient, a 22-year-old woman, received local anesthetic for extraction of a right mandibular molar and subsequently developed loss of taste on the right side of the tongue. When she visited our outpatient clinic 3 months later, atrophy of the fungiform papillae on the right side was observed. Her gustatory sense began to improve 4 months after the dental surgery and was normal at 13 months. From these findings we conclude that taste disturbance on the same side as the inferior alveolar nerve block in each case was due to direct injury to the chorda tympani and lingual nerves during administration of the local anesthetic. The results of EGM and FPD testing were diagnostic: atrophy of the fungiform papillae on the same side and disappearance of taste on the same side in the intravenous taste test provided complementary diagnostic information. The outcome was satisfactory in both cases.

Zinc deficiency and taste disorders.

Elemental zinc supplementation in daily dosages of 25-100 mg po appears to be an efficacious treatment for taste dysfunction secondary to zinc depletion. Insufficient evidence is available to determine the efficacy of zinc supplementation for the treatment of hypogeusia or dysgeusia secondary to drug therapy or medical conditions that do not involve low serum zinc concentrations.

Zinc salts for the treatment of olfactory and gustatory symptoms in psychiatric patients: a case series.

BACKGROUND: Zinc salts have been used extensively in medical settings to treat disorders of gustatory and olfactory function. However, zinc supplements have not been tested in psychiatric patients with smell or taste symptoms. METHOD: The authors examined the effects of zinc supplements on five consecutive patients with symptoms of abnormal taste and smell perception in the context of acute psychiatric illness or treatment. RESULTS: All five patients had complete or partial amelioration of these olfactory and gustatory symptoms after treatment with zinc sulfate or zinc gluconate, apparently independent of the improvement in their underlying psychiatric disorder. CONCLUSION: We recommend treating unusual olfactory and gustatory symptoms with zinc salts, independent of the treatment for the underlying psychiatric disorder.

Anorexia nervosa responding to zinc supplementation: a case report.

An emaciated 16-year-old female with anorexia nervosa was hospitalized for treatment of vomiting, epigastralgia and diarrhea. The finding of a taste disorder, low serum alkaline phosphatase activity and relatively low serum zinc level strongly suggested a zinc deficiency. Zinc was initially administered intravenously (40 mumol/day) for 7 days, then orally (15 mg elemental zinc/day) for about 60 days. Her digestive symptoms disappeared after the second day of intravenous treatment and she began to gain weight. She rapidly regained her normal weight after one month of receiving the oral zinc supplementation. Both exocrine pancreatic function and intestinal absorption were improved by the prolonged oral administration of zinc. In such cases zinc supplementation may be a therapeutic option in addition to psychologic and other approaches to management.