Lifestyle and dietary interventions for Ménière's disease

BACKGROUND

Ménière's disease is a condition that causes recurrent episodes of vertigo, associated with hearing loss and tinnitus. Lifestyle or dietary modifications (including reducing the amount of salt or caffeine in the diet) are sometimes suggested to be of benefit for this condition. The underlying cause of Ménière's disease is unknown, as is the way in which these interventions may work. The efficacy of these different interventions at preventing vertigo attacks, and their associated symptoms, is currently unclear.

OBJECTIVES

To evaluate the benefits and harms of lifestyle and dietary interventions versus placebo or no treatment in people with Ménière's disease.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 14 September 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs in adults with Ménière's disease comparing any lifestyle or dietary intervention with either placebo or no treatment. We excluded studies with follow-up of less than three months, or with a cross-over design (unless data from the first phase of the study could be identified).  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were: 1) improvement in vertigo (assessed as a dichotomous outcome - improved or not improved), 2) change in vertigo (assessed as a continuous outcome, with a score on a numerical scale) and 3) serious adverse events. Our secondary outcomes were: 4) disease-specific health-related quality of life, 5) change in hearing, 6) change in tinnitus and 7) other adverse effects. We considered outcomes reported at three time points: 3 to < 6 months, 6 to ≤ 12 months and > 12 months. We used GRADE to assess the certainty of evidence for each outcome.  MAIN RESULTS: We included two RCTs, one related to diet, and the other related to fluid intake and sleep. In a Swedish study, 51 participants were randomised to receive 'specially processed cereals' or standard cereals. The specially processed cereals are thought to stimulate the production of anti-secretory factor - a protein that reduces inflammation and fluid secretion. Participants received the cereals for three months. The only outcome reported by this study was disease-specific health-related quality of life.  The second study was conducted in Japan. The participants (223) were randomised to receive abundant water intake (35 mL/kg/day), or to sleep in darkness (in an unlit room for six to seven hours per night), or to receive no intervention. The duration of follow-up was two years. The outcomes assessed were 'improvement in vertigo' and hearing.  As these studies considered different interventions we were unable to carry out any meta-analysis, and for almost all outcomes the certainty of the evidence was very low. We are unable to draw meaningful conclusions from the numerical results.

AUTHORS' CONCLUSIONS

The evidence for lifestyle or dietary interventions for Ménière's disease is very uncertain. We did not identify any placebo-controlled RCTs for interventions that are frequently recommended for those with Ménière's disease, such as salt restriction or caffeine restriction. We identified only two RCTs that compared a lifestyle or dietary intervention to placebo or no treatment, and the evidence that is currently available from these studies is of low or very low certainty. This means that we have very low confidence that the effects reported are accurate estimates of the true effect of these interventions. Consensus on the appropriate outcomes to measure in studies of Ménière's disease is needed (i.e. a core outcome set) in order to guide future studies in this area and enable meta-analyses of the results. This must include appropriate consideration of the potential harms of treatment, as well as the benefits.

Antisecretory factor is safe to use as add-on treatment in newly diagnosed glioblastoma

PURPOSE

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Despite the best available treatment, prognosis remains poor. Current standard therapy consists of surgical removal of the tumor followed by radiotherapy and chemotherapy with the alkylating agent temozolomide (TMZ). Experimental studies suggest that antisecretory factor (AF), an endogenous protein with proposed antisecretory and anti-inflammatory properties, may potentiate the effect of TMZ and alleviate cerebral edema. Salovum is an egg yolk powder enriched for AF and is classified as a medical food in the European Union. In this pilot study, we evaluate the safety and feasibility of add-on Salovum in GBM patients.

METHODS

Eight patients with newly diagnosed, histologically confirmed GBM were prescribed Salovum during concomitant radiochemotherapy. Safety was determined by the number of treatment-related adverse events. Feasibility was determined by the number of patients who completed the full prescribed Salovum treatment.

RESULTS

No serious treatment-related adverse events were observed. Out of 8 included patients, 2 did not complete the full treatment. Only one of the dropouts was due to issues directly related to Salovum, which were nausea and loss of appetite. Median survival was 23 months.

CONCLUSIONS

We conclude that Salovum is safe to use as an add-on treatment for GBM. In terms of feasibility, adherence to the treatment regimen requires a determined and independent patient as the large doses prescribed may cause nausea and loss of appetite.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04116138. Registered on 04/10/2019.

The relationship between nutrition and Ménière's disease

Ménière's disease is an inner ear disease with attacks characterized by ear fullness, tinnitus, fluctuant sensorineural hearing loss and vertigo. Although pathophysiology of the disease is not fully known, endolymphatic hydrops are believed to play a role. Although there is no certain treatment procedure for Ménière's disease, some treatments are applied to prevent attacks, to treat the symptoms that occur during the attacks, and to prevent the permanent effects of the symptoms on the hearing and balance system. Lifestyle changes, dietary modifications, diuretics, vasodilator corticosteroids, intratympanic steroids, surgical methods are some of these treatment methods. Dietary modification includes a low sodium diet, a reduction in daily alcohol and caffeine intake, a gluten-free diet, and a new dietary approach to specially processed grains, all of which are first-line treatments. The goal of this review article is to examine the relationship between MD and dietary intervention, which is frequently used in the prevention and treatment of MD attacks.

The role of endogenous Antisecretory Factor (AF) in the treatment of Ménière's Disease: A two-year follow-up study. Preliminary results

PURPOSE

To evaluate the effects of increased endogenous Antisecretory Factor (AF) synthesis using specially processed cereals (SPC) in a sample of patients with defined unilateral Meniere's disease (MD), compared to the results of a treatment protocol of intravenous glycerol and dexamethasone.

MATERIALS AND METHODS

Twenty-six patients with unilateral MD were divided in 2 groups and treated with SPC and with intravenous glycerol and dexamethasone for 24 months. Audio-vestibular evaluation was performed before (T0) and every six months. The number of vertigo spells were evaluated before and after therapy and the Efficacy Index (EI) was calculated. Questionnaires for hearing loss, tinnitus and quality of life were administered.

RESULTS

EI decreased in the SPC group after 18 (T18) (p = .0017) and 24 (T24) months of therapy (p = .0111). There was a significant reduction for tinnitus score in the SPC group at T24 (p = .0131). No significant differences were found between the two groups at T0 (p = .4723), while a significant difference was found at T24 (p = .0027). Quality of life showed a significant improvement in daily activities in the SPC group (p = .0033) compared to the infusion therapy group. No statistically significant changes in PTA thresholds were found in both groups between T0 and T24.

CONCLUSION

The preliminary results of our study show a significant reduction of vertigo spells and a positive effect on tinnitus severity and on quality of life in patients with unilateral MD treated with SPC and when compared to patients treated with intravenous glycerol and dexamethasone. No effects on hearing thresholds were noted in both groups.

Food-induced stimulation of the antisecretory factor to improve symptoms in Meniere's disease: our results

PURPOSE

Specially processed cereals (SPC) that increase endogenous antisecretory factor (AF) synthesis have been proposed to improve symptoms of Meniere's disease (MD) with controversial results. The aim of this study was to evaluate the effects of SPC in patients with definite unilateral MD and compare the results to a treatment protocol with intravenous glycerol and dexamethasone.

METHODS

Thirteen patients with unilateral MD were treated with SPC and 13 patients were treated with intravenous glycerol and dexamethasone for 12 months. Audio-vestibular evaluation was performed before (T0) and at the end of the treatments (T12). The number of vertigo spells were evaluated before and after therapy and the Efficacy Index (EI) was calculated. Questionnaires for hearing loss (HHIA), tinnitus (THI) and quality of life (TFL) were administered.

RESULTS

EI decreased in the SPC group in the second semester compared to the first although not significantly (p = 0.6323). There was a significant reduction for THI score in the SPC group at T12 (p = 0.0325). No significant differences were found between the two groups at T0 (p = 0.4723), while a significant difference was found at T12 (p = 0.0041). Quality of life showed an improvement in daily activities in the SPC group compared to infusion therapy group.

CONCLUSION

Our study shows a reduced number of vertigo attacks and a positive effect on the discomfort generated by tinnitus and quality of life in patients with unilateral MD treated with SPC and when compared to patients treated with intravenous glycerol and dexamethasone. No effects on hearing thresholds were noted in both groups.

Antisecretory Factor Modulates GABAA Receptor Activity in Neurons

The antisecretory factor is an endogenous protein found in all mammalian tissues investigated so far. It acts by counteracting intestinal hypersecretion and various forms of inflammation, but the detailed mechanism of antisecretory factor (AF) action is unknown. We tested neuronal GABA_A receptors by means of AF-16, a potent AF peptide derived from amino acids 36-51 from the NH₂ part of AF. Cultured rat cerebellar granule cells were used, and the effects on the GABA-mediated chloride currents were determined by whole-cell patch clamp. Both the neurotransmitter GABA and AF-16 were added by perfusion of the experimental system. A 3-min AF-16 preincubation was more efficacious than 30 s in significantly elevating the rapidly desensitizing GABA-activated chloride current. No effect was found on the tonic, slowly desensitizing current. The GABA-activated current increase by AF-16 demonstrated a low k of 41 pM with a maximal increase of 37% persisting for some minutes after AF washout, independent from GABA concentration. This indicates an effect on the maximal stimulation (E%_Max) excluding an altered affinity between GABA and its receptor. An immunocytochemical fluorescence approach with anti γ2 subunit antibodies demonstrated an increased expression of GABA_A receptors. Thus, both the electrophysiological and the immunofluorescence approach indicate an increased appearance of GABA_A receptors on the neuronal membrane. The rationale of the experiments was to test the effect of AF on a defined neuronal population of GABA_A receptors. The implications of the results on the impact of AF on the enteric nervous system or on brain function are discussed.

Ménière's Syndrome or Disease: Time Trends in Management and Quality of Evidence Over the Last Two Decades

OBJECTIVE

To evaluate the evidence and trends in published literature on the treatment of Ménière's syndrome or disease (MS/D) by comparing studies published in the last two decades.

DATA SOURCES

A literature search was performed on AMED, EMBASE, HMIC, MEDLINE, PsycINFO, BNI, CINAHL, HEALTH BUSINESS ELITE, CENTRAL and Cochrane Ear, Nose and Throat disorders groups trials register using a combination of MeSH. The date of last search was October 2014.

STUDY SELECTION AND DATA EXTRACTION

Two hundred five studies (104 in decade I and 101 in decade II) were evaluated to report trends in the management of this condition, the differing levels of evidence published for each treatment modality, evaluate whether the guidelines published by the AAOHNS-Committee on Hearing and Equilibrium had been correctly employed, and whether the randomized controlled trials (RCTs) were compliant with the CONSORT guidelines.

RESULTS

The number of published RCTs almost tripled from decade I (1994-2003) to decade II (2004-2103). There was a significant decline in the use of surgical intervention (p = 0.013); however, the number of studies involving the use of intratympanic injection remained largely unchanged. There was a shift in the level of evidence in published studies; studies with level 1 evidence tripled from decade I to II (4.8 to 17.8%, respectively) (p = 0.03); however, compliance with the AAOHNS-CHE criteria for reporting treatment outcomes and the CONSORT checklist was still poor.

CONCLUSION

Although the evidence base on published literature on MS/D has improved over the last decade with an increase in emphasis on RCTs and quality of life (QoL) studies, a significant number of studies failed to follow AAOHNS-CHE criteria for reporting treatment outcome and the CONSORT criteria for reporting RCTs.