Ear infections could spark cravings for fatty foods

Ear infections could be making children overweight by damaging taste nerves and creating a bigger liking for fatty foods, scientists are warning.


Running through the middle ear on its way to the brain is a nerve called: “The Chorda Tympani” that carries taste sensations from the front of the tongue to the brain.
When a child gets a lot of ear infections – or cold and flu viruses – that taste nerve can be chronically bathed in inflammatory chemicals and infectious organisms, causing nerve damage. And taste damage may cause people to focus more on the creaminess and texture cues from fat, researcher say.

When Linda Bartoshuk, of the University of Florida College of Dentistry, had her Chorda Tympani nerves anesthetized as part of an experiment, milk felt like cream in her mouth. “Empirically we know that people with histories of ear infections do gain weight. Empirically we know that they rate high-fat, high-sweet foods as more pleasant. Are those two connected?,” Bartoshuk says. “Is it the increased pleasantness that makes them eat more, and makes them gain weight?     “That’s what we want to find out. It looks like it is.”

A string of studies on the possible link between ear infections and a craving for fatty food were presented Thursday at the American Pyschological Association’s annual meeting in Boston. One study involving about 450 children found toddlers who had tube surgery for ear infections were 2.5 times more likely to be overweight than two-year-old without tubes. The finding held after birth weight, family income, breast-feeding and other factors were taken into account.

“This isn’t in all kids, it’s a small proportion of kids and you probably have to have a fair number of ear infections,” says epidemiologist Kathleen Daly, of the University of Minnesota-Twin Cities. “But I think it’s something that’s very interesting, based on the epidemic in obesity that we seem to be experiencing in our country — even among very young children.”

In another study, scientists who re-analyzed data from a U.S. health survey in the 1960s that involved nearly 14,000 children aged six to 17 found that children who had their tonsils removed – once a common treatment for ear infections – were 40 per cent more likely to be overweight. Tonsillectomies can damage taste nerves at the back of the tongue. Teen girls who reported having ear infections or runny ears in the year before the survey were 1.9 times more likely to be overweight.

A study of 110 middle-aged women found those with signs of taste damage had a higher liking for sweet and high-fat foods – including salty foods like bacon, ham and potato chips. The women were also more likely to have wider waists.

In a large survey of adults, mostly academics, who attended a lecture series, Bartoshuk found that about 10 per cent of those who reported never having had an ear infection were obese. By contrast, 17 per cent who had ear infections when they were younger were obese.

Other researchers reported that preschoolers with a history of severe ear infections ate vegetables less, liked sweets more and appeared to be more overweight.

“We have an obesity problem in this country. Part of it could be genetic differences between people but the reality is our genetics haven’t changed that much in the last 100 years,” says John Hayes, a post-doctoral research fellow at Brown University in Providence, R.I. “That implies a large part of the obesity problem has to be from our environment. I think this is one small piece from the environmental puzzle – people who have a history of a lot of ear infections may be at higher risk for future obesity through the foods they choose to eat.”

In 2004, 26 per cent of two- to 17-year-olds in Canada were overweight or obese, up from 15 per cent in 1978. There’s no proof ear infections increase obesity risk. And, while obesity among preschoolers has doubled over the past 20 years, children have been getting ear infections for millennia.

As well, “we’re probably more effective at treating ear infections now than we’ve ever been,” says Kelowna, B.C. pediatrician Dr. Tom Warshawski, chair of the Childhood Obesity Foundation. “The increase in childhood obesity goes across the world. As societies get more wealthy, kids get more plump. It doesn’t seem to be associated with ear infections,” he said.

“Every so often in medicine we get surprised. When somebody proposed that ulcers were caused by bacteria they were laughed off the stage. Ten years later they win a Nobel prize for just that.”
Still, the theory that ear infections might be linked to increased obesity risk “just doesn’t seem to fit with all the other bits of information,” Warshawski said. It may be that children with a history of ear infections need to be more careful about the foods they eat, researchers say.

“It’s telling us that taste does way more than we used to think,” Bartoshuk says.


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