A report published online in the journal Free Radical Biology and Medicine described the discovery of researchers at the University of Michigan that including a combination of antioxidant vitamins and magnesium in oneโ€s nutritional regimen may help prevent noise-induced hearing loss.
Josef M. Miller MD, who is a professor in the Department of Otolaryngology at the University's Medical School, along with Colleen G. Le Prell, PhD and Larry F. Hughes treated guinea pigs with one of the following: vitamins A, C and E; magnesium; A, C and E plus magnesium, or a placebo one hour before and five days after a five hour exposure to 120 decibel sound pressure level noise (comparable to a jet engine at take-off). Although neither antioxidants nor magnesium alone appeared to be protective, animals that received both had significantly less hearing loss and sensory cell death than the other groups. The finding may be useful in developing a protective nutritional therapy for men and women whose employment involves significant exposure to noise, such as military occupations.
The protective mechanisms produced by pretreatment with the nutrients are a reduction in free radicals that form in the cochlea of the inner ear during and after noise exposure, and decreased constriction of blood flow to the inner ear. The nutrients may also have minimized damage to the auditory neurons caused by overstimulation. Treatment administered after noise exposure scavenged the free radicals that continue to from. "Free radical formation bursts initially, then peaks again during the days after exposure," Dr Le Prell explained.
"These agents have been used for many years, but not for hearing loss. We know theyโ€re safe, so that opens the door to push ahead with clinical trials with confidence weโ€re not going to do any harm," Dr Miller stated. "Ultimately, we envision soldiers would have a nutritional bar with meals and it would give them adequate daily protection."
"Other people would likely benefit by consuming a pill or nutritional bar before going to work in noisy environments, or attending noisy events like NASCAR races or rock concerts, or even using an iPod or other music player," Dr Le Prell added. "Based on an earlier study with other antioxidant agents, we think this micronutrient combination will work even post-noise."
"Similar combinations have been very effective in preventing macular degeneration, and many of these agents have been used with Alzheimerโ€s and Parkinsonโ€s diseases, stroke-like ischemia, and other conditions that involve neural degeneration," she noted. "Youโ€re always hoping as a basic scientist to find a commonality like that, across other disease processes.