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Damage to Taste Nerves May Be to Blame, Researchers Say
WebMD Health News
Reviewed By Louise Chang, MD
Early research suggests they are, and that damage to the nerves controlling taste may be to blame.
The research was presented for the first time today at the 116th annual convention of the American Psychological Association in Boston.
Taste researcher Linda M. Bartoshuk, PhD, of the University of Florida College of Dentistry, tells WebMD that over time, frequent ear infections may alter taste perception in a way that leads to a heightened preference for high-fat and highly sweetened foods, which, in turn, leads to obesity.
"Ear infections are relevant to taste because one of the most important taste nerves goes through the middle ear on the way to the brain," she says.
Another taste nerve is in the throat, Bartoshuk says, and researchers also presented findings showing an increased risk for obesity in children who have had tonsillectomies.
Ear Infections and Obesity
Bartoshuk says she first suspected a connection between ear infections and obesity about six years ago after analyzing findings from a survey she conducted to explore taste and health.
About 6,600 adults -- mostly academic professionals -- completed the survey, which included questions about past ear infections and current body mass index (BMI), a measure of obesity.
"We didn't expect to find ear infections associated with BMI, but that is what we saw," she says.
Bartoshuk then began looking for other research databases that included information on ear infection history and weight.
Several of these studies were presented at today's symposium, along with Bartoshuk's original research.
In one study involving middle-aged women tested for taste sensitivity, those who showed evidence of damage to taste nerves were more likely than women without evidence of nerve damage to prefer high-fat and highly sweetened foods. They were also more likely to have larger waists.
In another study, preschoolers with a history of frequent ear infections were found to eat fewer vegetables and more sweets than children who did not have frequent ear infections. They also tended to be heavier.
Epidemiologist Kathleen Daly, PhD, of the University of Minnesota-Twin Cities, reported on her work with children up to age 2, suggesting that chronic ear infections prior to this age are associated with higher BMIs (body mass index) around the second birthday.
"All of this is intriguing, but we don't really know what it means yet," Daly says.
Finally, re-examination of data from a large, national health survey conducted in the 1960s found a 30% increase in obesity risk among children who had tonsillectomies.
'Big Leap of Faith'
The research presented in Boston largely involved reanalysis of existing databases.
All agree that studies designed specifically to examine the question of whether chronic ear infections and tonsil surgery play a role in obesity are needed to prove the hypothesis.
"Given the epidemic of obesity in this country and the fact that children are becoming overweight at younger and younger ages, this really should be something we look at more carefully," Daly tells WebMD.
But ear specialist John W. House, MD, of the House Ear Institute in Los Angeles isn't so sure.
"We see thousands of children and adults with chronic ear infections at our clinic every year," he says. "If this association were real we would see it in our patients, but we don't."
University of Pittsburgh ear, nose and throat physician Barry Hirsch, MD, FACS, tells WebMD that the studies presented at the Boston symposium fall far short of proving a link between ear infections, tonsil surgery, and obesity.
House and Hirsch are both spokesmen for the American Academy of Otolaryngology -- Head and Neck Surgery.
"It is a big leap of faith to say from this type of research that ear problems cause obesity," he says.
SOURCES: 116th Annual Convention of the American Psychological Association, Boston, Aug. 14-17, 2008. Linda Bartoshuk, PhD, University of Florida College of Dentistry. Kathleen Daly, PhD, University of Minnesota - Twin Cities. John House, MD, president, House Ear Institute, Los Angeles; spokesman, American Academy of Otolaryngology - Head and Neck Surgery (AAO-HNS). Barry Hirsch, MD, FACS, associate professor of otolaryngology, University of Pittsburgh; spokesman, AAO-HNS. "Explaining Variance in Central Adiposity Through Taste Phenotype and Food Preference," Duffy, V., University of Connecticut.
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