Hearing Loss and Tinnitus

Hearing Loss and Tinnitus

1 Overview

Summary and Quick Facts

  • Hearing loss is one of the most common chronic conditions in older adults, with an estimated 36 million Americans reporting some degree of hearing impairment. Hearing loss and a related condition, tinnitus (ringing in the ears), can become severe obstacles in communicating and interacting with others, contributing to poor quality of life.
  • In this protocol, you will learn the causes of and risk factors for hearing loss and how it occurs, how to protect your hearing, and therapies for hearing loss and tinnitus, including targeted nutritional therapies.
  • Antioxidants are compounds that can neutralize damaging reactive oxygen species (ROS). Since ROS are involved in the development and progression of tinnitus and hearing loss, antioxidants represent a promising therapeutic strategy.

What are Hearing Loss and Tinnitus?

Hearing loss is one of the most common chronic conditions in older adults, second only to arthritis as the most handicapping condition. Hearing loss and tinnitus (ringing in the ears) can be obstacles to communication and social interactions, contributing to decreased quality of life.

Hearing loss can be conductive, sensorineural, or a combination of both. Conductive hearing loss is generally caused by damage to the outer or middle ear, while sensorineural is caused by damage to the inner ear and often progresses over time.

Natural interventions such as N-acetylcysteine and lipoic acid may help protect the ear and prevent or reverse hearing loss and tinnitus.

What are Causes and Risk Factors for Hearing Loss and Tinnitus?

  • Advanced age
  • Heart disease
  • High blood pressure
  • Diabetes
  • Smoking
  • Otosclerosis (abnormal bone growth in the middle ear)
  • Exposure to loud noises
  • Ototoxic drugs such as some antibiotics, chemotherapy drugs, and high doses of aspirin

What are Conventional Medical Treatments for Hearing Loss and Tinnitus?

  • Hearing aids
  • Tinnitus retraining therapy or other behavioral therapies
  • Masking devices or electrical stimulation for tinnitus
  • Stapedectomy (for otosclerosis)
  • Cochlear implants
  • Implantable bone conduction hearing devices

What are Emerging Therapies for Hearing Loss and Tinnitus?

  • Aldosterone replacement therapy
  • Neuromodulation, a process to correct the “misfiring” or “continuous” firing of neurons in the brain leading to tinnitus (eg, repetitive transcranial magnetic stimulation, deep brain stimulation, and acoustic stimulation).
  • Certain medications (eg, antidepressants and sleep aids) may help with tinnitus; however, more evidence is needed before drug strategies can be used reliably.

What Natural Interventions May Be Beneficial for Hearing Loss and Tinnitus?

  • N-acetylcysteine (NAC). NAC, a naturally occurring antioxidant that increases the production of glutathione, protected humans and animals against hearing loss from loud noises.
  • Acetyl-L-carnitine. Acetyl-L-carnitine may protect against mitochondrial damage that causes noise-induced and age-related hearing loss. Animal studies have shown that acetyl-L-carnitine can protect the cochlea and prevent drug-induced ototoxicity.
  • Lipoic acid. Lipoic acid can protect against age-related hearing loss and cochlear damage. A combination of lipoic acid with vitamin C and rebamipide improved hearing in elderly subjects.
  • Vitamins A, C, and E. Animal studies have shown that pretreatment with vitamins A, C, and/or E can protect against noise-induced and other types of hearing loss.
  • B vitamins. Elevated homocysteine levels, which are associated with B vitamin insufficiency, are linked with an increased risk of hearing problems. Specifically, low levels of folate and vitamin B12 are linked to hearing loss and tinnitus.
  • Magnesium. Magnesium can improve circulation, which is important as loud noises cause damage by decreasing blood flow to specialized ear cells. Magnesium deficiency can increase the risk of noise-induced hearing loss. Supplementation was shown to improve hearing that was damaged by noise.
  • Melatonin. Low plasma levels of melatonin are associated with high-frequency hearing loss among elderly subjects. Melatonin has protective effects and was shown to improve tinnitus in clinical studies.
  • Coenzyme Q10 (CoQ10). CoQ10 is an antioxidant that supports mitochondrial function. Supplementation reduced hearing loss in people with sudden sensorineural hearing loss and presbycusis (age-related hearing loss) and may alleviate tinnitus as well.
  • Taurine. Taurine can reverse certain biochemical processes behind hearing loss and may reduce or eliminate the ringing sound of tinnitus.
  • Other natural interventions that may be beneficial for hearing include ginkgo biloba, zinc, and omega-3 fatty acids.

2 Introduction

Hearing loss is one of the most common chronic conditions in older adults, with an estimated 36 million Americans reporting some degree of hearing impairment (Nash 2011; Mayo Clinic 2011). Next to arthritis, it is the second most common handicapping condition (Bielefeld 2010; NIHSenior Health 2012). Although hearing loss is more common with age, approximately 8.5% of American adults aged 20 to 29 have significant hearing loss, a number that appears to be rising (Agrawal 2008).

Hearing loss and a related condition, tinnitus or “ringing in the ears”, can become severe obstacles in communicating and interacting with others, contributing to poor quality of life. Moreover, hearing loss can lead to reduced neurologic activity in the parts of the brain that process speech, and atrophy in the parts that process sound in general (Samson 2001; Peelle 2011; Dalton 2003).

3 Understanding Hearing Loss and Tinnitus

Hearing loss can be conductive, sensorineural, or mixed, which is a combination of conductive and sensorineural. The type of hearing loss is correlated with the anatomic part of the ear affected (outer, middle, or inner ear). Generally, damage to the outer and middle ear causes conductive hearing loss, whereas inner ear damage results in sensorineural hearing loss (Medwetsky 2007).

Conductive Hearing Loss

Outer and middle ear conductive hearing loss could be caused by infections, trauma, congenital malformations or tumors in the outer ear. Otitis media, a common childhood disease that can also affect adults, is one of the most common types of ear infections to cause hearing loss; similarly, viral infections of the upper respiratory tract can affect the ear and cause temporary hearing loss. Trauma to the tympanic membrane, one of the middle ear structures that help translate sound waves into interpretable neurologic signals, can also result in conductive hearing loss. The tympanic membrane can become damaged by direct trauma, which can be caused by a foreign body such as a cotton swab (e.g., Q-tip®), infection, and sudden changes in air pressure (middle ear barotrauma) (Weber 2012).

Sensorineural Hearing Loss

Damage to the inner ear is usually responsible for hearing loss that progresses over time. Presbycusis, or age-related deterioration of hearing ability, is marked by the gradual loss of high frequency hearing on both sides in elderly individuals (Huang 2010). Presbycusis is also associated with tinnitus (i.e., ringing in the ears). Excessive noise can also cause sensorineural hearing loss that can gradually increase over time. Loud noise damages the delicate structures in the ear both due to trauma and accumulation of free radicals & excess glutamate, as well as altering intracellular magnesium and calcium levels (Prasher 1998). Infections and a condition called Meniere’s disease can also lead to inner ear damage and sensorineural hearing loss (Weber 2012; Mayo Clinic 2010).

Tinnitus

Closely linked to hearing loss is a condition known as tinnitus, characterized by a persistent ringing sensation in the ears. Although tinnitus can be triggered by a variety of causes, the majority of cases are associated with hearing loss (Roberts 2010). Researchers are still working to understand the process behind tinnitus. One popular hypothesis is when the hair cells (specialized nerve cells that help translate sound waves into interpretable signals for the brain, not to be confused with hair follicles) in the cochlea are damaged, some of the associated neurons partially lose the inhibitory regulation that keeps them from firing when no sound is present. As a result, these neurons send signals that the brain perceives as persistent noise. Supporting this hypothesis is that many people who suffer from tinnitus perceive the “ringing” in their ears to be of the same or similar frequency to their hearing deficits. Consequently, similar processes that lead to hearing loss may also lead to tinnitus; thus, interventions that prevent hearing loss may also prevent tinnitus (Roberts 2010).

4 Causes of and Risk Factors for Hearing Loss

A number of risk factors can predispose a person to hearing loss. Although advancing age is the most important risk factor, people with heart disease, high blood pressure, diabetes and an extensive smoking history are more likely to develop hearing loss (Helzner 2005; Bielefeld 2010). Otosclerosis, a condition involving abnormal bone growth within the middle ear, is associated with both conductive and sensorineural hearing loss (Liktor 2012; Ealy 2011; Bloch 2012; Deggouj 2009). In addition, hearing loss is more common in men (Agrawal 2008).

Noise Exposure. Repeated exposure to loud noises from occupational sources, recreational activities, or firearms strongly correlates with an increased risk of unilateral (hearing loss in one ear), bilateral (hearing loss in both ears), and high-frequency hearing loss (Agrawal 2008). According to a 2007 report, approximately 30 million Americans are exposed to dangerous levels of noise everyday, with 10 million adults and 5.2 million children affected by irreversible hearing loss due to excessive noise exposure (Seidman 2010). In addition, noise-induced hearing loss is the largest single category of compensated occupational disease in Europe (Mitchell 2009).

The National Institute of Occupational Safety and Health considers noise levels above 85 decibels to be harmful (Marsh 2011). Although sustained levels of loud noise are dangerous, impulse noise (i.e., large bursts of loud noise) can also damage hearing. In fact, research suggests that short exposure to very loud noise, such as that experienced by soldiers, can be more damaging to the auditory system than continuous noise (Clifford 2009).

Not only does excessive noise damage hearing, it may also increase blood pressure and heart rate, increase physiologic stress, and raise cortisol levels (Seidman 2010). Elevated cortisol levels are associated with an increased risk of osteoporosis, high cholesterol, hypertension, and insulin resistance (Tsigos 2002).

Ototoxic drugs. Some drugs have the potential to cause hearing loss or tinnitus because they are toxic to the ear or “ototoxic”. Examples of ototoxic drugs include high doses of aspirin, some antibiotics, some chemotherapy drugs, and some anti-inflammatory medications (Verdel 2008; Ligezinski 2002; Rybak 2007; Wecker 2004; Puel 2007). For example, high doses of aspirin in the range of 2,000 to 4,000 mg daily can cause tinnitus and hearing loss via peripheral effects on the cochlea and central effects on nerves involved in hearing. These effects usually subside within one to three days of discontinuing aspirin (Stolzberg 2012; McFadden 1984; Carlyon 1993; Day 1989). Risk of developing drug-induced hearing loss is greater in those with impaired kidney health or inner ear disorders (Ligezinski 2002).

5 How Hearing Loss Occurs

Over the years, scientists have gained a better understanding of how noise can damage the auditory system, particularly a part of the inner ear known as the cochlea. The cochlea contains specialized nerve cells, known as hair cells, which help translate sound waves into interpretable signals for the brain. Loud sounds damage hair cells through direct mechanical trauma and secondary metabolic damage. Direct mechanical trauma typically causes immediate structural damage to cochlear hair cells and can potentially cause immediately detectable hearing loss. The metabolic effects of loud noise, however, can accumulate for days or even weeks after initial sound exposure (Oishi 2011).

Loud noise affects metabolism in hair cells by decreasing oxygen supply and increasing energy demands. Loud noise can disrupt the flow in blood vessels that supply oxygen to hair cells, depriving these cells of nutrients needed to function and leading to cell damage through a process known as ischemia. At the same time, the increased stimulation due to noise forces the hair cells to be metabolically more active. The end result is that, during this period of intense stimulation, these hair cells burn through their energy reserves, resulting in the formation of reactive oxygen species (ROS). These ROS have the ability to damage proteins and lipids and can ultimately lead to death of the hair cells (Henderson 2006).

Hair cells may also be damaged by inflammatory mediators known as cytokines. Animal studies have found an increase in certain pro-inflammatory cytokines in response to loud noise. These cytokines include interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), two compounds that can be toxic to nerve cells at high levels (Fujioka 2006). In addition, overstimulation of hair cells can cause them to release large amounts of the neurotransmitter glutamate. Although glutamate release is needed to help translate sounds into neurological signals, too much glutamate can result in significant “excitotoxicity”, in which excessive stimulation damages nerve cells (Pujol 1999).

6 Protecting Your Hearing

Hearing loss was formerly assumed to be a normal part of aging, but we now realize there are measures one can take to prevent it. Because noise-induced hearing loss is a preventable form of acquired hearing loss, using physical ear protection can help preserve hearing. Historically, some of the most advanced forms of hearing protection were used by construction workers and individuals exposed to high levels of occupational noise. Studies have found that school-based communication sessions and video education about hearing protection can increase the use of hearing-preserving devices among workers; individually-tailored interventions appear to be more effective than general interventions (El Dib 2009). People working in other occupations that may expose them to harmful noise levels (e.g., employees at nightclubs) may also benefit from wearing hearing protection devices. However, studies have found that only a minority of these workers actually use adequate hearing protection (Gunderson 1997).

There are two main types of hearing protection: passive devices (e.g., earmuffs and earplugs) that mechanically block sound, and active devices that electronically cancel sound waves at the ear (Lusk 1997). From a practical standpoint, earplugs may be a better fit for reducing noise exposure throughout the day, both in terms of cost and ease of use (Bessette 2011; Schulz 2011).

The Importance of "Social Earplugs"

Physical ear protection has long been considered the “last line of defense” after noise reduction and regulation (Voix 2009; Seixas 2011). Until recently, however, most studies focused on noise in the workplace, where the threats are predictable and the solutions largely controllable. Evidence suggests that everyday noise (e.g., busy streets or entertainment venues) poses equally great hazards. Nightclubs, for example, often produce peak sound levels as high as 107 decibels (dB), while the maximum safe industrial sound level is considered to be 85 dB, and for regular environmental exposure is 70 dB (Katbamna 2008; Neitzel 2012; Lusk 1997; Gunderson 1997; Williams 2010). Urban dwellers may be exposed to chronic sound levels above 74 dB during their daily activities, and above 79 dB on public transit (Neitzel 2012; Katbamna 2008).

The best hearing protection available to most of us is the simple earplug, which produces passive noise reduction by blocking or dampening excessive sound energy before it lands on the eardrum. Experts believe that comfort should be the number one consideration, even above technical reduction of noise level. The argument, essentially, is that the “perfect” earplug that does not get worn is of little use compared to a comfortable one that will be worn regularly (Lusk 1997).

Another important feature of your hearing protection should be that it allows normal, natural communication. Too much sound reduction can reduce the ability to perceive speech naturally, or hear and respond to sounds that warn of hazards (Van Wijngaarden 2001). Excellent hearing protection is now available in the form of “social ear plugs” that allow reduction of ambient noise levels while remaining attentive to the speech of those nearby.

When it comes to how much sound will be blocked, not all earplugs are the same. Like sun tan lotion with different SPFs, there are different protection factors for earplugs. This is known as the Noise Reduction Rating (NRR). The NRR is a rating system set up by the Environmental Protection Agency (EPA) to represent how much noise earplugs will block when worn properly. An important factor in determining a product’s NRR is its attenuation. The opposite of amplification, attenuation is any reduction in signal strength. Attenuation for hearing protection devices is determined by a panel of human subjects over a range of frequencies. The average attenuation is then used in calculating the NRR. The higher the NRR, the more noise the earplug will block out.

Choose hearing protection based on its comfort, “social graces,” and of course, cost. Comfortable, effective, musician-grade earplugs can be found at a reasonable cost from reputable manufacturers.

7 Therapies for Hearing Loss and Tinnitus

Hearing Loss

Hearing aids. One of the most common treatments for hearing loss is the use of hearing aids. Hearing aids are devices that amplify sound waves, making it easier to hear sounds. There are a variety of hearing aids available, and people who are hard of hearing typically need to go to a trained specialist to determine exactly what type of hearing aid is appropriate (Weber 2012a). Studies estimate, however, that only about 15% to 20% of people who could benefit from hearing aids use them. This may be due to cost or because people often consider mild hearing loss inconsequential, and therefore do not seek treatment (Chien 2012; Natalizia 2010).

Hormone Replacement Therapy for Hearing Loss

One interesting development in the field of hearing loss research is the potential link between aldosterone levels and hearing loss. Aldosterone is a hormone that helps to regulate blood pressure and electrolyte levels. Research has found that higher aldosterone levels may help protect the cochlea from age-related hearing loss (Tadros 2005). A case study has also been published detailing a child with genetically low aldosterone levels and otherwise unexplained sensorineural hearing loss (Rubio-Cabezas 2010). Currently, the Tahoma Clinic in Seattle is recruiting volunteers for a study examining the effects of aldosterone supplementation on hearing loss (Tahoma Clinic 2012).

Tinnitus

Behavioral Therapies. Treatment for tinnitus includes behavioral therapies (i.e. therapeutic behavior modification). One specialized therapy, known as tinnitus retraining therapy, aims to train the brain to ignore symptoms of tinnitus unless specifically focusing on ringing in the ears. Cognitive-behavioral therapy and biofeedback can also be used to help learn to manage responses of the mind and body to tinnitus, thus allowing people to minimize its effects on their daily lives (Andersson 1995; Dinces 2012; Pantev 2012).

Masking and electrical stimulation. Sound-masking devices are commonly used to treat tinnitus. These devices emit low levels of noise designed to help reduce the perception of tinnitus (Vernon 2003). However, it has been seen that masking by itself is not as effective in reducing the severity of tinnitus as some other treatment options, such as relaxation techniques, counseling, and tinnitus retraining (Hobson 2010).

Electrical stimulation of the cochlea, via electrodes placed on parts of the ear, can also provide relief from tinnitus in people who also have hearing loss (Konopka 2001; Dinces 2012).

Neuromodulation. One emerging treatment for tinnitus is neuromodulation, a process that helps correct the “misfiring” or continuous “firing” of neurons in the brain leading to tinnitus. Different methods and devices for this purpose are being researched (University of Nottingham 2012). One of them, called repetitive transcranial magnetic stimulation (rTMS), uses magnetic pulses to modulate brain activity; preliminary results show that it is effective for reducing tinnitus symptoms (De Ridder 2007). Deep brain stimulation, a technique in which electrodes are carefully placed in certain areas of the brain in order to deliver therapeutic electrical signals, has also been researched as a potential treatment for tinnitus (Cheung 2010). One of the most novel therapies to treat tinnitus is acoustic stimulation. A device used for this treatment has been found to be both safe and effective (Tass 2012) and has the added advantage of being relatively small and portable (University of Nottingham 2012).

Medications. Some drugs have been shown to partially relieve tinnitus or ease emotional distress associated with tinnitus or hearing loss; these include antidepressants, sleep aids, and antipsychotics (Salvi 2009; Belli 2012). However, efficacy has proven inconsistent in trials and more evidence is needed before the best drug strategy can be determined (Darlington 2007; Hoare 2011).

8 Targeted Nutritional Therapies

Antioxidants

Antioxidants are compounds that have the ability to neutralize damaging reactive oxygen species (ROS). Since ROS are involved in the development and progression of tinnitus and hearing loss, antioxidants represent a promising therapeutic strategy (Sergi 2004; Savastano 2007; Joachims 2003).

N-acetyl cysteine

N-acetyl cysteine (NAC) is a naturally occurring antioxidant that has been used for years to treat acetaminophen overdose and break up mucus; it also increases the production of glutathione, one of the most prevalent antioxidants in the body (Kopke 2007). NAC has been studied as a potential therapeutic agent to protect hair cells from damage due to excessive noise as well. A 2011 study on military recruits found that NAC was able to protect the cochlea from damage due to noise from firing a gun in an enclosed space (Lindblad 2011). Animal studies have also found that NAC has a protective effect against continuous loud noises (Lorito 2006; Bielefeld 2007) as well as impulse noise (Kopke 2005). Another animal study showed that NAC may reduce noise-induced hearing loss even when administered after exposure to dangerous levels of noise (Coleman 2007). NAC has generated interest in the field of hearing loss because it is safe for human consumption and has already been approved for some uses in humans (e.g., treatment of acetaminophen toxicity) (Kopke 2007).

Acetyl-L-carnitine

Mitochondria are the energy powerplants of the cell. They are also the site of ROS production, especially when the cell is under stress. In cochlear hair cells, mutations in mitochondrial DNA and declining function of the mitochondria have been found to cause age-induced hearing loss (Yamasoba 2007). As a result, compounds that help maintain mitochondrial health, such as acetyl-L-carnitine, may help protect cells from damage. Animal studies have found that acetyl-L-carnitine is able to protect the cochlea from both continuous and impulse noise damage as well as prevent loss of hair cells (Kopke 2002; Kopke 2005). Acetyl-L-carnitine was also found to reduce mutations in mitochondrial DNA, suggesting that it could prevent not only noise-induced hearing loss, but also age-related hearing loss (Seidman 2000). Much like NAC, acetyl-L-carnitine appears to be effective even when administered after exposure to loud noise(s) (Coleman 2007; Du 2012). In one animal study, acetyl-L-carnitine was shown to protect against ototoxicity induced by the chemotherapeutic drug cisplatin (Gunes 2011).

Lipoic acid

Lipoic acid has been found to reduce age-related hearing loss (Seidman 2000). Preliminary animal studies have also found that lipoic acid can help protect against noise-induced hearing loss and preserve inner-ear mitochondrial function (Diao 2003; Peng 2010). This may be partly due to the effect it has on glutathione (i.e., a naturally occurring antioxidant in the body). Studies have found increasing glutathione levels help protect the cochlea from damage due to loud noises (Le Prell 2007). In one laboratory study, lipoic acid was shown to increase glutathione levels in nerve cells, protecting them from damage (Jia 2008). Lipoic acid may also be able to counteract the action of toxins (e.g., carbon monoxide) that aggravate the effects of noise and make normally safe levels of volume harmful to the ear (Pouyatos 2008). In a clinical trial among 46 elderly subjects with hearing loss, 8 weeks of treatment with lipoic acid (60 mg/day) combined with two other free radical scavengers (vitamin C [600 mg/day] and rebamipide [300 mg/day]) significantly improved hearing at all frequencies tested (Takumida 2009).

Vitamins

Dietary supplementation with vitamins that have antioxidant capabilities can help protect the hair cells of the cochlea. One animal study showed that a 35-day pretreatment regimen of vitamin C may be able to protect against noise-induced hearing loss (McFadden 2005). Similarly, supplementing animals with certain forms of vitamins A and E have shown significant protective effects (Hou 2003; Ahn 2005). The length of time vitamins need to be taken prior to noise exposure may vary depending on the vitamin. For example, vitamin E appears to be effective with three days of pretreatment, vitamin A may only require two days to be effective, and Vitamin C may require a longer pretreatment period. In addition, taking vitamins in combination may be more effective than any one of them alone (Le Prell 2007). For example, a combination of B-vitamins, vitamins C & E, and L-carnitine protected rodents from cisplatin ototoxicity (Tokgoz 2012).

Folate and Vitamin B12

Folate and vitamin B12 are important for the functioning of many cells in the body, including nerve cells. They also help reduce levels of homocysteine, a potentially toxic compound found in the body. Elevated homocysteine levels are linked to an increased risk of hearing problems (Gok 2004; Gopinath 2010). Vitamin B12 injections (1 mg for 7 days followed by 5 mg on day 8) protected against noise-induced hearing loss in healthy volunteers aged 20 to 30 years (Quaranta 2004). Researchers have found that patients with low levels of folate in their blood are more likely to develop hearing loss (Gok 2004; Lasisi 2010; Gopinath 2010), and that low vitamin B12 levels are associated with hearing loss (Gok 2004) and tinnitus (Shemesh 1993).

Magnesium

Because loud noise impairs blood flow to the cochlea, researchers have also examined compounds that could help improve circulation to the hair cells and prevent their death. Magnesium is known to help expand blood vessels and improve circulation; it also helps control the release of glutamate, one of the major contributors to noise-induced hearing loss (Le Prell 2011). Animal studies have found that magnesium deficiency increases the risk of noise-induced hearing loss (Sendowski 2006b; Scheibe 2002). A combination of magnesium and other antioxidants may synergistically prevent hearing loss, potentially because magnesium’s ability to increase blood flow also helps transport the protective antioxidants (Le Prell 2011). Other animal studies have determined that magnesium can protect against impulse noise damage (Sendowski 2006a; Haupt 2003). Magnesium’s benefits have been demonstrated in human trials as well; magnesium supplementation (122 mg daily for ten days) reduced noise-induced hearing loss in men aged 16-37 years (Attias 2004). Studies have also found that both intravenous magnesium and oral magnesium supplementation may be beneficial for other types of hearing loss, such as sudden sensorineural hearing loss (Gordin 2002; Coates 2010).

Melatonin

Melatonin, a hormone critical for healthy sleep (Wurtman 2012), has powerful antioxidant properties. Animal studies have found that it is effective at preventing hearing damage after exposure to loud noises (Karlidag 2002; Bas 2009). It is also effective at treating other types of hearing loss caused by ROS, such as due to the chemotherapy drug cisplatin (Lopez-Gonzalez 2000). Researchers have discussed the potential for melatonin to act as a protectant against age-related hearing loss (Martinez 2009). For example, it was noted in a study that low plasma levels of melatonin were associated with significant high-frequency hearing loss among elderly subjects (Lasisi 2011).

Additionally, melatonin has been tested as a treatment for tinnitus, both in combination with the medication sulpiride (an atypical antipsychotic) and on its own. On its own, melatonin provides relief from tinnitus, especially in people with significant sleep problems (Rosenberg 1998; Megwalu 2006; Reiter 2011).When combined with sulpiride, melatonin reduces the perception of tinnitus by diminishing the activity of dopamine, a chemical in the brain. In one study, sulpiride alone relieved tinnitus in 56% of subjects while melatonin alone reduced tinnitus in 40%. However, when used together, 81% of subjects reported relief from their tinnitus symptoms (Lopez-Gonzalez 2007).

Ginkgo Biloba

Ginkgo biloba, a commonly used herbal supplement, has attracted interest as a means of protecting against hearing loss as well as a treatment for tinnitus. Early animal studies found that when a standardized preparation of Ginkgo biloba extract was given as a supplement to animals, it reduced behavioral manifestations of tinnitus (Jastreboff 1997). This extract, at a dose of 160 mg daily over a 12 week period, was also effective at reducing symptoms in humans (Morgenstern 2002). However, other studies have found negligible or no effect (Hilton 2010; Canis 2011); therefore, more research is needed in this area. Ginkgo biloba may also be effective at preventing hearing loss that causes tinnitus; an animal study found that a Gingko biloba extract was able to reduce drug-induced oxidative damage to hair cells in the cochlea (Yang 2011).

Coenzyme Q10

Coenzyme Q10(CoQ10) supports mitochondrial function and has significant antioxidant properties (Quinzii 2010). Animal studies have found that supplementation with CoQ10 reduced noise-induced hearing loss and the death of hair cells (Hirose 2008; Fetoni 2009, 2012). Human studies have also yielded promising results, as 160-600 mg of CoQ10 daily was found to reduce hearing loss in people with sudden sensorineural hearing loss and presbycusis (Ahn 2010; Salami 2010; Guastini 2011). Also, a small preliminary trial found that CoQ10 supplementation alleviated tinnitus in those whose CoQ10 blood levels were initially low (Khan 2007). Another small trial found CoQ10 may slow progression of hearing loss associated with a mitochondrial genetic mutation (Angeli 2005).

Zinc

Zinc, a mineral involved in many physiological processes (including nervous system function), has antioxidant and anti-inflammatory properties (Frederickson 2000; Prasad 2008). Evidence suggests that inadequate zinc intake may be associated with impaired hearing (Kang 2012). Researchers have found that zinc supplementation may be helpful in treating some forms of hearing loss (Yang 2010). In addition, low levels of zinc correlate with perceived loudness of tinnitus in afflicted individuals (Arda 2003).

Omega-3 fatty acids

Long-chain omega-3 (n-3) polyunsaturated fatty acids, long recognized as important for health, may also affect hearing loss; a preliminary study found that participants with the highest blood levels of these beneficial fats suffered the least amount of hearing loss over time (Dullemeijer 2010). In another study, greater fish or fish oil consumption was associated with less hearing loss among nearly 3,000 subjects over 50 years of age. The authors remarked that “dietary intervention with n-3 PUFAs could prevent or delay the development of age-related hearing loss” (Gopinath 2010).

Taurine

Taurine plays a vital role in hearing. In fact, studies have found that in some cases, taurine can reverse the biochemical processes behind hearing loss (Liu 2006; Liu 2008a). Other studies have demonstrated that taurine can almost completely eliminate the ringing in the ears associated with tinnitus (Brozoski 2010).

Much of the damage to hearing occurs not in the mechanical parts of the ear, but rather in the nerve cells that convert sound waves into the electrical energy that is perceived in our brains. Like other nerve cells, these so-called “hair cells” depend on the flow of calcium ions into and out of the cell. Taurine helps restore and control normal calcium ion flow in auditory cells (Liu 2006; Liu 2008b).

Taurine improves the hearing ability in animals exposed to drugs like the antibiotic gentamicin, which is notoriously toxic to hearing (Liu 2008a). And in a boon for the 17% of us troubled by chronic tinnitus (ringing in the ears), taurine may be helpful in quieting the noise (Galazyuk 2012). Animal studies using human equivalent doses of 700 mg to 3.2 grams per day of taurine over the course of several weeks demonstrate near-complete resolution of tinnitus with taurine supplementation (the animals had been trained in tasks that are sensitive to distraction by tinnitus) (Brozoski 2010). And a human pilot study has shown encouraging results, with 12% of people responding to taurine supplementation (Davies 1988).

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This information (and any accompanying material) is not intended to replace the attention or advice of a physician or other qualified health care professional. Anyone who wishes to embark on any dietary, drug, exercise, or other lifestyle change intended to prevent or treat a specific disease or condition should first consult with and seek clearance from a physician or other qualified health care professional. Pregnant women in particular should seek the advice of a physician before using any protocol listed on this website. The protocols described on this website are for adults only, unless otherwise specified. Product labels may contain important safety information and the most recent product information provided by the product manufacturers should be carefully reviewed prior to use to verify the dose, administration, and contraindications. National, state, and local laws may vary regarding the use and application of many of the therapies discussed. The reader assumes the risk of any injuries. The authors and publishers, their affiliates and assigns are not liable for any injury and/or damage to persons arising from this protocol and expressly disclaim responsibility for any adverse effects resulting from the use of the information contained herein.

The protocols raise many issues that are subject to change as new data emerge. None of our suggested protocol regimens can guarantee health benefits. Life Extension has not performed independent verification of the data contained in the referenced materials, and expressly disclaims responsibility for any error in the literature.

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