Photobiomodulation in the Treatment of Dysgeusia in Patients with Long COVID: A Single-Blind, Randomized Controlled Trial.

Objective: The aim of this study is to evaluate local and systemic photobiomodulation (PBM) in patients with COVID-19-related dysgeusia, with the expectation of improving taste dysfunction. Background: PBM has garnered attention as a potential therapy in long COVID, a condition characterized by many persistent symptoms following the acute phase of COVID-19. Among these symptoms, dysgeusia, or altered taste perception, can significantly affect patients' quality of life. Emerging research suggests that PBM may hold promise in ameliorating dysgeusia by modulating cellular processes and reducing inflammation. Further clinical studies and randomized controlled trials are essential to establish the efficacy and safety of PBM for the treatment of dysgeusia in long COVID, but initial evidence suggests that this noninvasive modality may offer a novel avenue for symptom management. Methods: Seventy patients experiencing dysgeusia were randomly assigned to receive active local and systemic PBM (n = 34) or simulated PBM (n = 36). Low-power laser (red wavelength) was used at 18 spots on the lateral borders of the tongue (3 J per spot), salivary glands (parotid, sublingual, and submandibular glands-3 J per spot), and over the carotid artery for 10 min (60 J). Alongside laser therapy, all patients in both groups received weekly olfactory therapy for up to 8 weeks. Results: Dysgeusia improved in both groups. At weeks 7 and 8, improvement scores were significantly higher in the PBM group than in the sham group (p = 0.048). Conclusions: Combined local and systemic PBM, as applied in this study, proved effective and could serve as a viable treatment option for alleviating dysgeusia in long-COVID patients. Clinical Trial Registration: RBR-2mfbkkk.

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.

Dysgeusia induced and resolved by focused ultrasound thalamotomy: case report.

Dysgeusia, or distorted taste, has recently been acknowledged as a complication of thalamic ablation or thalamic deep brain stimulation as a treatment of tremor. In a unique patient, left-sided MR-guided focused ultrasound thalamotomy improved right-sided essential tremor but also induced severe dysgeusia. Although dysgeusia persisted and caused substantial weight loss, tremor slowly relapsed. Therefore, 19 months after the first procedure, the patient underwent a second focused ultrasound thalamotomy procedure, which again improved tremor but also completely resolved the dysgeusia. On the basis of normative and patient-specific whole-brain tractography, the authors determined the relationship between the thalamotomy lesions and the medial border of the medial lemniscus-a surrogate for the solitariothalamic gustatory fibers-after the first and second focused ultrasound thalamotomy procedures. Both tractography methods suggested partial and complete disruption of the solitariothalamic gustatory fibers after the first and second thalamotomy procedures, respectively. The tractography findings in this unique patient demonstrate that incomplete and complete disruption of a neural pathway can induce and resolve symptoms, respectively, and serve as the rationale for ablative procedures for neurological and psychiatric disorders.

Dietary Supplementation with Monosodium Glutamate Suppresses Chemotherapy-Induced Downregulation of the T1R3 Taste Receptor Subunit in Head and Neck Cancer Patients.

(Background) We investigated the effect of dietary supplementation with monosodium glutamate (MSG) on chemotherapy-induced downregulation of the T1R3 taste receptor subunit expression in the tongue of patients with advanced head and neck cancer. (Methods) Patients undergoing two rounds of chemoradiotherapy were randomly allocated to a control or intervention group (dietary supplementation with MSG at 2.7 g/day during the second round of chemotherapy). The relative expression of T1R3, a subunit of both umami and sweet taste receptors, in the tongue was assessed by quantitative polymerase chain reaction analysis. Dysgeusia was assessed with a visual analog scale and daily energy intake was evaluated. (Results) T1R3 expression levels in the tongue, taste sensitivity, and daily energy intake were significantly reduced after the first round of chemotherapy compared with before treatment. Furthermore, these parameters significantly decreased after the second round of chemotherapy, but the extent of decrease was significantly attenuated in the MSG group compared with the control group. (Conclusions) MSG supplementation suppresses chemotherapy-induced dysgeusia, possibly due to the inhibition of the T1R3-containing taste receptor downregulation in the tongue, thereby increasing energy intake in patients with advanced head and neck cancer.

Can atypical dysgeusia in depression be related to a deafferentation syndrome?

Atypical dysgeusia such as having the sensation of a sweet tooth is an uncommon clinical presentation in severe depression. First, we present the case of a 67 year-old-man admitted to the psychiatric ward for depression after a suicide attempt by drug ingestion. The patient manifested a sweet taste sensation in the upper and lower gums that increased with mood swings and notably with severe depressive symptoms. Blood tests showed an elevated serum creatinine level (115 µmol/L), a normocytic anemia (hemoglobin 6.5 mmol/L; MCV 96 fL) and a deficit in vitamin B12 (122.4 pmol/L). The patient received vitamin B12 supplementation and was treated with clomipramine, lithium, mirtazapine, modafinil, and olanzapine. He was discharged after improvement of his depressive symptoms and decrease in the sweet taste. On follow-up, the patient's dysgeusia had subsided. Second, we hypothesize that the atypical dysgeusia may have been induced by vitamin B12 deficiency and medical comorbidities, leading to deafferentation (development of erroneous mouth mucosae sensations felt by the patient). This could have been increased by depression. Dysgeusia in elederly patients with depression should be extensively investigated in order to elucidate somatic contributing factors but it may not resolve until improvement of the depressive symptoms.

The effects of zinc on radiation-induced dysgeusia: a systematic review and meta-analysis.

PURPOSE: Many head and neck cancer patients who receive radiation therapy experience radiation-induced dysgeusia (RID), which has no standard treatment. The only supplement controlled clinical trials have evaluated for the treatment of RID is zinc. However, the results of these and other studies investigating the use of zinc for RID have been inconsistent. To assess the validity of zinc as a treatment for RID, we conducted a systematic literature search and performed a meta-analysis to determine the extent to which zinc affects RID incidence and the degree to which ongoing RID responds to zinc. METHODS: We searched the Ovid MEDLINE, Ovid Embase, PubMed, and Cochrane Library databases to identify studies investigating the use of zinc-based therapy for RID in head and neck cancer patients treated with radiation that were published between January 1, 2003, and November 9, 2017. Using American Society of Clinical Oncology criteria, we selected studies with a high level of evidence for inclusion in the meta-analysis. RESULTS: Of the 32 full-text articles eligible for inclusion, three were included in the final review and meta-analysis. The meta-analysis showed that, compared with placebo, zinc reduces the incidence of RID (risk ratio, 0.72; 95% confidence interval, 0.67-0.92) but does not improve taste acuity more rapidly following radiation therapy (risk ratio, 2.58; 95% confidence interval, 0.97-6.88). CONCLUSION: Our findings indicate that zinc-based therapy reduces the incidence of RID but has a minimal effect on ongoing RID. Our findings also highlight the need for additional evidence-based research on this topic.

Safety and tolerability of prescription omega-3 fatty acids: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Omega-3 fatty acids [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] are widely recommended for health promotion. Over the last decade, prescription omega-3 fatty acid products (RxOME3FAs) have been approved for medical indications. Nonetheless, there is no comprehensive analysis of safety and tolerability of RxOME3FAs so far. METHODS: A systematic review of randomized controlled trials (RCTs) was carried out based on searches in six electronic databases. The studies involving marketed RxOME3FA products were included, and adverse-effect data were extracted for meta-analysis. Subgroup analysis and meta-regression were conducted to explore the sources of potential heterogeneity. RESULTS: Among the 21 included RCTs (total 24,460 participants; 12,750 from RxOME3FA treatment cohort and 11,710 from control cohort), there was no definite evidence of any RxOME3FA-emerging serious adverse event. Compared with the control group, RxOME3FAs were associated with more treatment-related dysgeusia (fishy taste; p = 0.011) and skin abnormalities (eruption, itching, exanthema, or eczema; p < 0.001). Besides, RxOME3FAs had mild adverse effects upon some non-lipid laboratory measurements [elevated fasting blood sugar (p = 0.005); elevated alanine transaminase (p = 0.022); elevated blood urea nitrogen (p = 0.047); decreased hemoglobin (p = 0.002); decreased hematocrit (p = 0.009)]. Subgroup analysis revealed that EPA/DHA combination products were associated with more treatment-related gastrointestinal adverse events [eructation (belching; p = 0.010); nausea (p = 0.044)] and low-density lipoprotein cholesterol elevation (p = 0.009; difference in means = 4.106mg/dL). CONCLUSION: RxOME3FAs are generally safe and well tolerated but not free of adverse effects. Post-marketing surveillance and observational studies are still necessary to identify long-term adverse effects and to confirm the safety and tolerability profiles of RxOME3FAs.

Dysgeusia in deep brain stimulation for essential tremor.

Dysgeusia, or foul taste, is a rarely reported side effect in patients who have undergone deep brain stimulation (DBS) in the thalamus for essential tremor. This retrospective study evaluated the incidence, nature, neurophysiological and anatomical location of dysgeusia following DBS. Of 52 patients who had undergone DBS for essential tremor, eight (15%) reported dysgeusia, which was described as a "metallic," "sour," "foul," or "cold" taste in the mouth. Dysgeusia was separate and distinguishable from paresthesia. Dysgeusia was more frequently reported with bilateral than unilateral DBS implants (6 of 27 (22%) vs. 2 of 25 (8%) patients, respectively). The anatomical locations of the contacts causing dysgeusia were measured on postoperative MRI, and compared to those from seven control patients who did not experience dysgeusia after receiving bilateral DBS implants. Leads causing dysgeusia were more posterior than non-dysgeusia-associated leads (4.5 ±â€¯1.2 vs. 5.7 ±â€¯1.8 mm anterior to the posterior commissure, respectively, P < .001). Intraoperative microelectrode recording indicated that these contacts were in the sensory region of the thalamus. Intraoperative testing found that low sensory threshold for paresthesia predicted the development of dysgeusia postoperatively (1.5 ±â€¯0.5 V vs. 3.3 ±â€¯1.9 V; P < .05). These data indicate that taste perception can be altered in the human through DBS, with posterior leads likely within the sensory region of the thalamus. Dysgeusia can be reduced by changing stimulation parameters, or surgical revision of the lead.

The Efficacy of Plasma Rich in Growth Factors for the Treatment of Alveolar Osteitis: A Randomized Controlled Trial.

PURPOSE: To investigate the efficacy of plasma rich in growth factors (PRGF; BTI Biotechnology Institute, San Antonio, Spain) for the treatment of alveolar osteitis compared with a positive control (Alvogyl; Septodont, Maidstone, Kent, UK). MATERIALS AND METHODS: This single-center, single-blinded, randomized, 2-treatment, parallel study was conducted in a UK dental hospital. All healthy adults who presented with alveolar osteitis after tooth extraction over a 3-month period were invited to participate. Each socket was randomized and treated with 1 of 2 treatment modalities, a test treatment (PRGF) or a positive control (Alvogyl). After treatment, patients were reviewed at 3 and 7 days by a second clinician blinded to the treatment given. Outcome measures included pain, exposed bone, inflammation, halitosis, dysgeusia, and quality-of-life assessment. RESULTS: Thirty-eight patients with data from 44 sockets (22 in the PRGF group and 22 in the Alvogyl group) were analyzed. The PRGF group showed significantly faster bone coverage and significantly decreased inflammation and halitosis (P < .05) compared with the control group receiving Alvogyl. There was no significant difference for pain, quality-of-life measures, or dysgeusia between groups. CONCLUSION: PRGF predictably treated alveolar osteitis after tooth extraction compared with the conventional standard treatment of Alvogyl, which has been used for many years. PRGF could be considered an alternative treatment for alveolar osteitis and indeed appears to have considerable advantages over Alvogyl.

A state-of-the-art review of the management and treatment of taste and smell alterations in adult oncology patients.

PURPOSE: The purpose of this review was to examine studies of interventions for the prevention and management of taste and smell alterations (TSA) experienced by adult oncology patients. METHODS: Articles published between 1993 and 2013 were identified by searching CINAHL, MEDLINE and Food Science & Technology Abstracts (FSTA) and were included if they were in English and focused on adult oncology patients. Only interventions within the scope of nursing practice were reviewed. RESULTS: Twelve articles were identified for inclusion. Four research groups examined zinc supplementation, with two claiming that zinc supplementation was an effective intervention and two claiming it had no effect on TSA. The remaining research groups examined eight other interventions, with varying results. Marinol, megestrol acetate and Synsepalum dulcificum interventions appear promising. CONCLUSION: Based on this review, there does not yet appear to be an effective approach for preventing or managing TSA in adult oncology patients. Although some interventions show promise, further research is necessary to determine their efficacy.

Nutrition aspects of lung cancer.

Lung cancer is the most common type of cancer, excluding nonmelanoma skin cancer, and is the leading cause of cancer death in the United States. Notable carcinogens involved in the development of lung cancer include smoking, secondhand smoke, and radon. Lung cancer is divided into 2 major types: non-small-cell lung cancer, the most prevalent, and small-cell lung cancer. Treatment includes surgery, chemotherapy, radiation, or a combination of the same. Medical nutrition therapy is often required for nutrition-related side effects of cancer treatment, which include but are not limited to anorexia, nausea and vomiting, and esophagitis. The best protection against lung cancer is avoidance of airborne carcinogens and increased consumption of fruits and vegetables. Studies have shown that smokers taking large amounts of beta-carotene and vitamin A supplements had increased lung cancer incidence and mortality. However, ingestion of beta-carotene from foods, along with a diet rich in fruits and vegetables, has a protective role against lung disease. The use of complementary and alternative medicine by lung cancer patients is prevalent; therefore, clinicians should investigate whether complementary and alternative therapies are used by patients and advise them on the use of these therapies to avoid any potential side effects and interactions with conventional therapies. The article concludes with a case study of a patient with non-small-cell lung cancer and illustrates the use of medical nutrition therapy in relation to cancer treatment side effects.

Dysgeusia related to urinary obstruction from benign prostatic disease: a case control and qualitative study.

Anecdotal reports suggest that dysgeusia may be related to a variety of systemic factors, including bladder outflow obstruction. This is a hospital-based case-controlled study involving 111 patients who were admitted to urological wards for transurethral resection of the prostate for benign prostatic disease with age- and sex-matched control of 137 subjects. We used a semi-structured questionnaire by a trained interviewer at admission (preoperative), at the postoperative period and at follow-up between 4-6 months (median 5 months). Analysis used unpaired t-test and chi(2) test. The incidence of dysgeusia was 22% in the study group and 13% in the control group (P=N.S.). However, strikingly, the dysgeusia in the study group was relieved promptly by relief of urinary obstruction in 100% of cases and did not return within the follow-up period. The mechanism of the dysgeusia associated with dysuria in benign prostatic disease is unknown, but we suggest that the dysgeusia could be from the stress of dysuria or due to a release of an unknown chemical from the urinary tract or an overflow of neural impulse from pontine/cortical micturition centres to the taste centres. An association between dysgeusia and dysuria has not been described before.

Disorders of smell, taste, and food intake in a patient with a dorsomedial thalamic infarct.

BACKGROUND: We report that a lasting deficit in the hedonic character of olfactory and gustatory perception can be observed in bilateral dorsomedial and intralaminar thalamic lesions. CASE DESCRIPTION: A 68-year-old patient abruptly presented with vigilance disorders associated with a reduction of olfactory and gustatory perceptions. A severe drop in appetite for foods and a weight loss of 10 kg were observed, which were partially reversed with time. Two years later, the main persisting disorder was a change in the quality of perceptions: odors and taste were perceived either in a neutral way, their pleasant character having disappeared, or as unpleasant. However, identification was preserved. MRI showed that lesions principally involved the dorsomedial thalamic nuclei and the adjacent part of the intralaminar nuclei. CONCLUSIONS: This case suggests that the dorsomedial thalamus may play a role in the hedonic perception of food, thus affecting short-term regulation of food intake, and may possibly have a role in the long-term control of body weight.

Nutrition and cancer: physiological interrelationships.

There are many tumors that have paraneoplastic syndromes. Furthermore, location of certain tumors can result in very specific effects on the host, especially tumors in the hypothalamus, the intestinal tract, or the liver. Finally, tumors of the immune system can have significant distant consequences. However, from direct experimental evidence, from model systems, and from the utilization of nutritional manipulation in the treatment of cancer, the data suggest very strongly that there is no unique cancer malnutrition. Early diagnosed cancer does not show malnutrition as a presenting symptom. Furthermore, all metabolic disturbances can be explained on the basis of the metabolic differences of tumor cells and normal cells and are very frequently proportional to the bulk of the tumor. The cachexia that is associated with malignancies is more likely cachexia in cancer patients than it is a specific cancer cachexia, unless the tumor burden is very large. This point was clearly made in a short review of the causes of cachexia in nearly 1500 cancer patients in Russia (145). Brennan also feels that most cases of malnutrition are uncomplicated starvation, and cancer cachexia has many features seen in major injury or sepsis (16). This distinction has great implications in the management of cancer patients.