Cheers to Better Hearing: Or not? Research is split on whether drinking helps or hurts hearing a
If you've ever had a drink in a noisy bar, you may have noticedthat the noise level seemed to increase as the evening wore on and more drinks were consumed. "Cocktail party deafness" not only causes drinkers to speak louder so they can be heard, it can also result in a morning-after sensation of mild hearing loss.
British researchers, led by Tahwinder Upile, M.D., of University College London, have found that consuming alcohol immediately reduces a person's ability to hear, at least in the short term. Thirty volunteers had their hearing tested before beginning to drink. They then drank the same amount of alcohol, and had their hearing tested again. According to the study, published in BMC Ear, Nose and Throat Disorders in 2007, "alcohol increased the hearing threshold in all individuals." In other words,
the minimum volume a drinker needed to be able to hear grew. What's more, they found that "alcohol specifically blunts lower frequencies affecting mostly 1000Hz, which is the most crucial frequency for speech discrimination." Within a week, however, hearing appeared to have returned to its prior level.
Over the past decade, scientists have been examining the effect drinking has on hearing health. They have found that alcohol has both protective and destructive effects on hearing ability, although as might be expected, heavier drinking does more damage.
One of the most recent studies is also one of the most long term. The Prospective Study of Alcohol Use and Hearing Loss in Men, published in August 2010 in the journal Ear and Hearing, examined nearly 27,000 men every two years since 1986. According to research lead Sharon Curhan, M.D., of Boston's Brigham and Women's Hospital, there was "no association between level of alcohol intake and risk of hearing loss."
Interestingly, the study noted that "among those with lower intake of vitamin B12, however, higher consumption of alcohol, specifically liquor, was associated with an increased risk of hearing loss." Researchers said a possible relation between alcohol consumption, vitamin B12which occurs naturally in animal products such as meat, fish, poultry, and dairy, and is also in fortified breakfast cerealsand hearing loss is worth additional investigation.
The Effects of Heavy Drinking
It's well known that heavy, long-term alcohol intake can seriously worsen your health. This includes your hearing. A 2004 German study published in the journal Alcoholism: Clinical & Experimental Research found that heavy drinking caused damage to the brainstem, resulting in hearing loss. Elisabeth Stephanie Smith, M.D., a member of the Ear, Nose and Throat Clinic at Germany's University of Ulm, told the health news website Medical News Today that not only does chronic alcohol consumption cause brain shrinkage, "but it also leads to defects of the central auditory tracks, which causes delays in neurotransmission time."
Smith studied brainstem auditory evoked potentials (BAEPs), currents that circulate within the brain, to evaluate how much damage had been done by alcohol intake to the hearing ability of those in the study. "When an acoustic stimulus on the brain is presented, a particular current response is activated. This response can be detected by electrodes," she said. As a result, Smith was able to track the BAEP response in the brains of individuals who had consumed varying quantities of alcohol throughout their lifetimes.
"Drinkers with lower lifelong alcohol consumption still have a normal amount of healthy nerves in the brain, whereas drinkers with high lifelong alcohol consumption have a much larger amount of defective nerves," says Tilman Keck, M.D., Smith's colleague and an assistant clinical professor in the Department of Otorhinolaryngology at the University of Ulm. But they found that damage to the auditory nerves still occurred in the brains of social drinkers.
The German study bore out the results of an earlier study conducted by Karen J. Cruickshanks, Ph.D., and her colleagues at the University of Wisconsin, published in the Journal of the American Geriatrics Society in 2000. While examining an older population for evidence of alcohol's effect on hearing loss, Cruickshanks found that "there was an increase in the odds of having a highfrequency hearing loss in those with a history of heavy drinking." In this study that was defined as four or more drinks a day.
A Possible Protective Effect
But among those whose consumption of alcohol was moderate, here defined as more than one glass of wine, beer, or liquor per week, the Wisconsin researchers said this was "inversely associated with hearing loss." Not only is there evidence of "a modest protective association of alcohol consumption and hearing loss," but hearing loss is also not inevitable with aging, they concluded.
Likewise, a 2008 study from the University of Antwerp in Belgium, published in the Journal of the Association for Research in Otolaryngology, found that moderate alcohol consumption, defined here as at least one drink a week, "was seen to have a protective effect."
Australian scientists examined the effects of both alcohol and smoking on hearing loss among 2,956 people over age 50. Their study, led by Bamini Gopinath, Ph.D., and others at the University of Sydney and published in Ear and Hearing in 2010, found "a significant protective association between the moderate consumption of alcohol [defined as between one and two drinks a day] and hearing function in older adults," compared with nondrinkers.
They also discovered that "when the joint effects of alcohol consumption and smoking on hearing were explored, there was a trend for alcohol to have a protective relationship with hearing loss in smokers, but this was not statistically significant."
Writing in the Summer 2010 issue of this magazine, Jochen Schacht, Ph.D., of the Kresge Hearing Research Institute at the University of Michigan, said resveratrol, a naturally occurring substance in red wine, shows promise as a protector of inner ear hair cells. Resveratrol has also been shown to fight heart disease and, in studies performed on mice, extend life span.
The mixed verdict on the effects of alcohol on hearing is also manifest in relation to tinnitus, or ringing in the ears. Researchers at the Welsh Hearing Institute at University Hospital Wales examined 100 people who experienced chronic tinnitus and the results were published in the British Journal of Audiology in 1995. Twenty-two percent of the sample reported that drinking worsened tinnitus and 16 percent reported that alcohol improved tinnitus. The majority of those in the study found no effect.
Few health professionals would encourage those with hearing loss to take up drinking as a treatment. While research is still ongoing, the wisest course in terms of alcohol intakelike many other thingsis very likely to be one of moderation.
Jamie Morrison is a staff writer.
Alcohol During Pregnancy and Newborn Hearing Loss
While children born with fetal alcohol syndrome (FAS) tend to suffer from mental retardation and physical deformities, relatively few studies have been undertaken to ascertain the effects of FAS on hearing. What studies there have been have shown different conclusions.
A 1997 study by researchers at Wayne State University in Detroit examined 22 infants born with FAS and found that 77 percent "had intermittent conductive hearing loss due to recurrent serious otitis media [ear infections] that persisted from early childhood into adulthood." The study, published in Alcoholism: Clinical & Experimental Research, also found that 27 percent "had sensorineural hearing loss in addition to the conductive hearing loss."
Another report the same year, conducted by doctors at the Bowman-Gray School of Medicine in Winston- Salem, N.C., evaluated 14 children diagnosed with FAS and another 48 with the less severe fetal alcohol exposure (FAE). The researchers presented their conclusions at the 101st annual meeting of the American Academy of OtolaryngologyHead and Neck Surgery Foundation in San Francisco. They said "mild to profound sensorineural hearing loss (average hearing loss of 43 decibels) was found in 43 percent of the patients with FAS, 19 percent with FAE. Also, 71 percent of the FAS patients had chronic middle ear disease requiring treatment or surgery; the corresponding rate for FAE patients was 43 percent."
But in contrast, a more recent study, published in the Canadian Journal of Clinical Pharmacology in 2007, and spearheaded by experts at the Hospital for Sick Children in Toronto, found that only 11 percent of the 41 children evaluated had hearing loss of at least 16 decibels. This figure is within the normal range and so the researchers concluded FAS was not a cause of hearing loss.
Since whether alcohol plays a role in hearing loss remains unclear, expectant mothers should play it safe to protect their children's hearing and general health. J.M.
