Hearing Support Formula
CLINICAL STUDIES ON THE FOLLOWING INGREDIENTS:
Antioxidants And Hearing Loss
Effect of antioxidant supplementation on the auditory threshold in sensorineural hearing loss: a meta-analysis: *
Hearing loss is conceptualized as any impairment of the ability to hear and/or detect speech or environment sounds, regardless of cause, type, or degree. It may occur at different stages of life; during pregnancy or childbirth, in childhood, adulthood or old age. It should be noted that aging is the most common cause of sensorineural hearing loss followed by noise-induced hearing loss, and both are closely related to the formation of reactive oxygen species. Dietary antioxidant supplementation has been employed as a therapeutic strategy to prevent and/or delay the risks of major human diseases.
Results: Based on 977 potentially relevant records identified through the search in the databases, ten full-text publications were retrieved for further evaluation. The increase in threshold at the 4 kHz frequency was statistically higher in the control group (1.89 [1.01–2.78], p < 0.0001) when compared to the NAC group and the ginseng group, whereas at 6 kHz, the threshold increase was higher in the control group (1.42 [−1.14–3.97], p = 0.28), but no statistically significant differences were found between groups.
Role of antioxidants in prevention of age-related hearing loss: a review of literature: *
Age-related hearing loss (ARHL), also known as presbycusis, is one of the most prevalent chronic degenerative conditions. It is characterized by a decline in auditory function. ARHL is caused by the interaction of multiple factors, including cochlear aging, environment, genetic predisposition, and health comorbidities. The primary pathology of ARHL includes the hair cells loss, stria vascularis atrophy, and loss of spiral ganglion neurons as well as the changes in central auditory pathways. The research to date suggests that oxidative stress and mitochondrial DNA deletion (mtDNA) play a major role in pathophysiology of ARHL. Therefore, similar to other otological conditions, several studies have also showed that antioxidants can slow ARHL, but some also indicate that antioxidant therapy is not a magic elixir that will prevent or treat hearing loss associated with aging completely, but why? All available clinical trials, including animal and human studies, in English language that examined the protective effects of antioxidants against ARHL were reviewed. Materials were obtained by searching ELSEVIER, PubMed, Scopus, Web of knowledge, Google Scholar databases, Clinical trials, and Cochrane database of systematic reviews. Although ARHL has been shown to be slowed by supplementation with antioxidants, particularly in laboratory animals, a few studies have investigated the effect of interventions against ARHL in humans. High-quality clinical trials are needed to investigate if ARHL can be delayed or prevented in humans. However, it seems that targeting several cell-death pathways is better than targeting the only oxidative stress pathway.
Folic Acid And Hearing Loss
Folic acid deficiency induces premature hearing loss through mechanisms involving cochlear oxidative stress and impairment of homocysteine metabolism *
Nutritional imbalance is emerging as a causative factor of hearing loss. Epidemiologic studies have linked hearing loss to elevated plasma total homocysteine (tHcy) and folate deficiency, and have shown that folate supplementation lowers tHcy levels potentially ameliorating age-related hearing loss. The purpose of this study was to address the impact of folate deficiency on hearing loss and to examine the underlying mechanisms. For this purpose, 2-mo-old C57BL/6J mice (Animalia Chordata Mus musculus) were randomly divided into 2 groups (n = 65 each) that were fed folate-deficient (FD) or standard diets for 8 wk. HPLC analysis demonstrated a 7-fold decline in serum folate and a 3-fold increase in tHcy levels. FD mice exhibited severe hearing loss measured by auditory brainstem recordings and TUNEL-positive-apoptotic cochlear cells. RT-quantitative PCR and Western blotting showed reduced levels of enzymes catalyzing homocysteine (Hcy) production and recycling, together with a 30% increase in protein homocysteinylation. Redox stress was demonstrated by decreased expression of catalase, glutathione peroxidase 4, and glutathione synthetase genes, increased levels of manganese superoxide dismutase, and NADPH oxidase-complex adaptor cytochrome b-245, α-polypeptide (p22phox) proteins, and elevated concentrations of glutathione species. Altogether, our findings demonstrate, for the first time, that the relationship between hyperhomocysteinemia induced by folate deficiency and premature hearing loss involves impairment of cochlear Hcy metabolism and associated oxidative stress.
Effects of folic acid supplementation on hearing in older adults: a randomized, controlled trial *
Background: Age-related hearing loss is a common chronic condition of elderly persons. Low folate status has been associated with poor hearing.
Objective: To determine whether folic acid supplementation slows age-related hearing loss.
Design: Double-blind, randomized, placebo-controlled trial conducted from September 2000 to December 2004.
Setting: The Netherlands.
Participants: 728 older men and women recruited from municipal and blood bank registries with plasma total homocysteine concentrations 13 micromol/L or greater serum and vitamin B12 concentrations 200 pmol/L or greater at screening, and no middle ear dysfunction, unilateral hearing loss, or pathologic ear conditions unrelated to aging.
Intervention: Daily oral folic acid (800 microg) or placebo supplementation for 3 years.
Measurements: 3-year change in hearing thresholds, assessed as the average of the pure-tone air conduction thresholds of both ears of the low (0.5-kHz, 1-kHz, and 2-kHz) and high (4-kHz, 6-kHz, and 8-kHz) frequencies.
Results: Initial median hearing thresholds were 11.7 dB (interquartile range, 7.5 to 17.5 dB) for low frequencies and 34.2 dB (interquartile range, 22.5 to 50.0 dB) for high frequencies. Sixteen participants (2%) were lost to follow-up. After 3 years, thresholds of the low frequencies increased by 1.0 dB (95% CI, 0.6 to 1.4 dB) in the folic acid group and by 1.7 dB (CI, 1.3 to 2.1 dB) in the placebo group (difference, -0.7 dB [CI, -1.2 to -0.1 dB]; P = 0.020). Folic acid supplementation did not affect the decline in hearing high frequencies.
Ginkgo Biloba And Hearing Loss
An efficacy comparison of betahistin, trimetazidine and ginkgo biloba extract in patients with tinnitus *
Objectives: This study aims to investigate the efficacy of trimetazidine, betahistine and ginkgo biloba extract in the treatment of tinnitus.
Patients and methods: Complete clinical data of 90 patients (48 males, 42 females; mean age 52.3±15.1 years; range 20 to 61 years) who received betahistine, trimetazidine and ginkgo biloba extract for three months were retrospectively analyzed. The patients were divided into three groups including 30 in each group according to treatments received. Pre-treatment and post-treatment scores of tinnitus disability questionnaire were compared statistically.
Results: There was no statistically significant difference between pre-treatment scores of tinnitus disability questionnaire among all three groups (p>0.05), while there was a statistically significant difference among the groups following treatment (p=0.019, p<0.05). After a-three-month treatment, a decrease of 19.7±15.5 units in trimetazidine group, 12.2±12.7 units in betahistine group, and 3.80±5.9 units in ginkgo biloba extract group were found to be statistically significant, compared to the mean pretreatment tinnitus disability questionnaire scores (p=0.002, p<0.01).
Conclusion: Our study results suggest that trimetazidine, betahistin and ginkgo biloba extract reduce tinnitus symptoms. However, symptomatic relief can be mostly achieved with trimetazidine treatment.
Green Tea Extract And Hearing Loss
Role of green tea polyphenols in noise-induced hearing loss *
Objective: To investigate the role and mechanism of action of green tea polyphenols in noise-induced hearing loss. Methods: Male specific pathogen-free guinea pigs were randomly divided into normal control group with 9 guinea pigs, noise exposure group with 36 guinea pigs, and green tea polyphenol intervention group with 36 guinea pigs. Auditory brainstem response (ABR) threshold shift was examined before noise exposure and at 1, 3, 7, and 14 days of noise exposure. The surface preparation of cochlear basilar membrane was used for hair cell count and the morphology of hair cells was also observed. Western blot was used to observe the expression of cysteinyl aspartate-specific protease-9 (caspase-9) and cysteinyl aspartate-specific protease-3 (caspase-3) in cochlear tissue. Results: Both the noise exposure group and the green tea polyphenol intervention group had an increase in ABR threshold after noise exposure, and the green tea polyphenol intervention group had a significantly lower ABR threshold shift than the noise exposure group at all time points (P<0.05). Both groups had enlargement, atrophy, or loss of hair cells after noise exposure, and at 7 and 14 days of noise exposure, the noise exposure group had a significantly higher rate of abnormal hair cells than the green tea polyphenol intervention group (P<0.05). Both groups had an increase in the expression of caspase-9 and caspase-3 after noise exposure, and the noise exposure group had a significantly greater increase than the green tea polyphenol intervention group (P<0.05). Conclusion: Green tea polyphenols can reduce noise-induced hearing loss and hair cell injury, possibly by regulating the expression of caspase-9 and caspase-3.