According to researchers, the finding suggests that it may be possible to create a pill that protects against noise-induced and even age-related hearing loss in humans.
Two studies found that giving supplements containing antioxidants [beta carotene and vitamins C and E] and the mineral magnesium to test animals before they were exposed to a loud noise prevented both temporary and permanent hearing loss.
In the first study, vitamin supplements protected guinea pigs exposed to four hours of 110-decibel noise, similar to levels reached at a rock concert. In the second study, vitamin supplements prevented hearing loss in mice exposed to a single loud noise.
The findings were to be presented Wednesday at the Association for Research in Otolaryngology annual meeting. Previous research showed that antioxidants can also protect hearing days after exposure to loud noise.
"What is appealing about this vitamin 'cocktail' is that previous studies in humans, including those demonstrating successful use of these supplements in protecting eye health, have shown that supplements of these particular vitamins are safe for long-term use," University of Florida researcher Colleen Le Prell, senior author of the studies, said in a news release.
About 26 million Americans have noise-induced hearing loss, according to the U.S. National Institute on Deafness and Other Communication Disorders, which funded the two studies. Temporary noise-induced hearing loss typically goes away after a few hours or days as cells in the inner ear heal. But repeated noise-induced temporary hearing loss can lead to permanent hearing loss. Le Prell and colleagues believe that prevention of temporary hearing loss may help prevent permanent hearing loss.
Le Prell and colleagues are currently studying the use of vitamin supplements in college students who wear MP3 music players and in noise-exposed military troops and factor workers in Spain and Sweden.
"Ear protection, such as ear plugs, is always the best practice for the prevention of noise-induced hearing loss, but in those populations who don't or can't wear hearing protection, for people in which mechanical devices just aren't enough, and for people who may experience unexpected noise insult, these supplements could provide an opportunity for additional protection," Le Prell said.
The American Academy of Family Physicians has more about noise-induced hearing loss.
-- Robert Preidt
SOURCE: University of Florida, news release, Feb. 17, 2009
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