Posted on 02/22/2024 2:18:17 AM PST by Red Badger
Hearing loss, frequently due to exposure to loud noises, is a significant health problem. Its biological underpinning may well be due to what we consider a trace mineral: zinc.
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How do we hear?
Sound waves, really variations in air pressure, are collected and directed towards the eardrum by our outer ear, where we hang our glasses and the ear canal. Those waves strike the eardrum (tympanic membrane), transmitting those vibrations to the three small bones of the middle ear - the malleus (hammer), incus (anvil), and stapes (stirrup). The mechanical linkage of the three amplifies the incoming vibrations and transfers them through the oval window, a membrane-covered opening that leads to the fluid-filled cochlea.
Cochlea" is derived from the Latin word for "snail shell" or "spiral," reflecting the distinctive and intricate spiral form of the cochlea, which is a critical component of the auditory system responsible for converting sound vibrations into electrical signals that the brain can interpret as sound. Its spiral shape is essential for its function, allowing different regions within the cochlea to be sensitive to specific sound frequencies, a concept known as tonotopic organization. High-frequency sounds stimulate cells near the base of the cochlea, while low-frequency sounds stimulate cells toward the apex.
Tiny sensory cells with hair-like structures (stereocilia ) on their surface, termed hair cells, bend in response to the motion of the cochlea’s fluid. The bending of the hair cells triggers the release of neurotransmitters, creating electrical signals. The auditory nerve picks up these signals, which carry the information to the brain. Today’s story lies in the presence of zinc, which modulates those neurotransmissions. [1]
There are four main types of hearing loss:
* Conductive Hearing Loss, caused by obstructions in the outer or middle ear
* Sensorineural Hearing Loss, related to issues in the inner ear or hearing nerve
* Mixed Hearing Loss, a combination of conductive and sensorineural loss
* Auditory Neuropathy Spectrum Disorder, where damage to the inner ear or hearing nerve disrupts the organization of sound in the brain.
Sensorineural hearing loss is the most common form and may be due to aging, exposure to loud noises, certain medications, and various medical conditions. While exposure to loud sounds often explains hearing loss in aging rockers, it is a far more significant problem for our armed forces. Hearing loss is the second most common service-related disability, following closely on the heels of another hearing affliction, tinnitus.
Noise-induced hearing loss (NIHL) impacts roughly one out of every five adults. In addition to being a hindrance to social activity, hearing loss in adults 45 to 64 was associated with a 42% increase in dementia compared to their hearing-able colleagues. NIHL works through various mechanisms, including the loss of hair and supporting cells in the cochlea and their synaptic connection to the underlying neurons. Zinc, an essential but trace mineral, is critical in the enzymatic activity of many metabolic pathways but is most often bound up in the enzymes that accelerate those reactions. A small amount of zinc, “labile” zinc, is found in the chemical pouches, the vesicles, that are released when nerves are excited and pass signals on to the next cell in the chain. Labile zinc modulates neurotransmission and sensory processing. Zinc concentrations are the highest in our inner ears, the transformer of vibrations into sounds, but little is known about zinc’s role in signaling.
The researchers using a mouse and a specific gene, Slc30a3, involved in zinc transport across those vesicles, found that it was found and expressed predominantly in the cochlea on those sound-translating hair cells. When mice were exposed to loud noises significant enough to cause changes in auditory signaling consistent with impairment, zinc levels rose, and their distribution within their cochlea changed – a response the researchers termed “zinc dysregulation.” Further testing identified the protein expressed by Slc30a3 as the proximate cause of the dysregulation. In a final series of experiments, the researchers found that “knocking out” the Slc30a3 gene and reducing the levels of zinc by chelation [2] restored hearing to pre-noise exposure levels.
As with all good scientific research, we are left with more questions than answers. Labile zinc has been known to be involved in other traumatic neurologic injuries, and how these elevated levels of zinc harm hearing is unknown. On the other hand, chelation may prove to be a useful target to mitigate hearing loss due to loud noises.
Source: Cochlear zinc signaling dysregulation is associated with noise-induced hearing loss, and zinc chelation enhances cochlear recovery PNAS DOI: 10.1073/pnas.2310561121
[1] This YouTube video does a great job explaining the underlying anatomy and function of the cochlea
[2] Chelation describes the process of bonding zinc to other molecules, in this instance, reducing the amount of labile zinc present.
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I’ll give it a whirl. While only limited evidence it helps with tinnitus, I’ve had tinnitus since childhood which maybe different than those who developed over time
FTA:
“hearing loss in adults 45 to 64 was associated with a 42% increase in dementia compared to their hearing-able colleagues.”
While my Dad had non-existent dementia at age 97, when his hearing aids failed him, he’d stare down at the carpet when there were conversations all around him.
My BIL, who also wore hearing aids, suggested he buy an overnight cleaning device (which was merely a tiny heater). And that—that—had made all the difference!
I wonder if LWB has enough zinc.
I skimmed the article and thought it was saying too much zinc was the culprit.
From the last paragraph: “As with all good scientific research, we are left with more questions than answers. “
I’m going to try this. My hearing has been messed up since my last trip to the range two weeks ago.
Thanks for posting. Health/life BUMP!
I take zinc daily.
I don’t think it helps my hearing.
I take zinc daily to keep from getting viruses. My hearing is fine so I don’t know if it helps that or not.
I likewise take 50mg zinc daily, for the same reasons (immune system, antivirus, etc.).
My hearing is quite compromised from 60 years of playing loud (LOUD!) rock and roll in bands, from high-school garage bands, to large combos in noisy clubs, etc. Can't hear much above 2kHz, and have terrible loud tinnitus. So I have high-end DSP programmable hearing aids (Oticon "More") which are a life saver in conversations and noisy rooms.
I have no idea whether the daily zinc is helping or hurting my hearing, but I believe it's helping keep me healthy, so I intend to continue it.
See #13 above.
Yep. All I know is Mr. GG2 and I haven’t had a sniffle since Nov 2022. We take the Zelenko protocol everyday and it keeps us healthy.
BKMK
I lost my hearing when I was 16. I must preface that with the fact I didn't have hearing in my left ear, which I'd either lost at birth, or at a very early age.
Anyway, the doctors told me I'd had Labyrinthine Encephalitis, which became complicated by viral Influenza and the mumps, which unfortunately went down on me. the hearing went about a week later, fading in the course of a day.
My parents, who worked on that Saturday, made an appointment with a doctor, who unfortunately flew the coop for a vacation in Florida when I couldn't get there in time.
As it turned out, they later told my parents I was quite lucky to have survived the ordeal. I can attest...I was quite sick.
As events would have it, the literature states in such cases, the hearing usually does not return. I'm hoping something like this might resurrect a modicum of hearing, which a hearing aid might assist.
When I say I'm deaf, I'm not kidding. There's nothing there.
CA....
Got mine the day after the J+J Covid jab.
Looking back would NEVER have gotten a vacs. We listened to liars on steroids.
Did you learn and use sign language?
I’ve had chronic ear problems for 30 years. Went to a new ENT who talked me into getting an Osia Baha II. I have a plate in my head and the hearing aid is attached magnetically. My doctor said hearing issues contributes to Alzheimer’s.
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