THURSDAY, Aug. 14 (HealthDay News) -- Damage caused by chronic ear infections in children may alter their sense of taste, making fatty and sweet foods more desirable and increasing the risk of obesity.

That's the conclusion of four new studies presented Thursday at the American Psychological Association's annual meeting in Boston.

In the first study, Kathleen Daly, a professor of otolaryngology at the University of Minnesota, found that "middle ear nerve damage may play a role in affecting taste in children with recurrent ear infections or chronic ear disease who get [drainage] tubes. This damage may increase intake of fattening foods."

For the study, Daly's team followed children from birth to 2 years of age who had been treated with tubes for ear infections.

"There was a trend, but not significant, for recurrent ear infection to lead to overweight," Daly said. "Other studies have reported a similar relationship between ear infections and overweight. We did not find evidence for the reverse hypothesis: larger and heavier children were more prone to ear infections and tubes than smaller and lighter children."

In the second study, led by John Hayes of Brown University, researchers found that among 110 middle-aged women with a sense of taste consistent with nerve damage, those who preferred sweet and high-fat foods tended to have larger waists.

"Surprisingly, we found that the single best predictor of body weight was not how much saturated fat they took in and not how often they ate high-fat foods, but was how much they liked high-fat and sweet foods," Hayes said.

Hayes noted that taste can vary genetically, but also through exposure to environmental changes. "Particularly with damage to the taste system and we think this happens from ear infections," he said.

Another study by Hayes' group found that preschoolers with a history of severe ear infections ate fewer vegetables, more sweets and tended to be heavier.

In the third study presented Thursday, led by Howard Hoffman, an epidemiologist at the U.S. National Institute on Deafness and Other Communication Disorders, researchers found that removing the tonsils had an effect on whether children would be overweight.

"Taste does have an impact on selection of food and diet," Hoffman said. "A tonsillectomy may damage one of the nerves that carry taste information. In addition, ear infections can also alter taste. Altering taste does have an effect on the preferences for food," he said.

Hoffman's team reexamined data on 13,887 children who took part in the National Health Examination surveys during the 1960s. The researchers found that children who had had their tonsils removed were at greater risk of being overweight. Among children aged 6 to 11 who'd had a tonsillectomy, they were 40 percent more likely to be overweight at the time of the survey, compared with children who did not have a tonsillectomy.

What's more, teenage girls who'd had a tonsillectomy were 30 percent more likely to be overweight, the researchers found. Hoffman noted that tonsillectomies were a common treatment back in the 60s for chronic ear infections, which can alter the taste buds and affect eating habits.

"This data is not conclusive, but it's suggestive," he said.

In the final study, Linda Bartoshuk, of the University of Florida College of Dentistry, and colleagues collected data on 6,584 people who attended a lecture series. These men and women, between 16 and 92 years old, were asked about their history of ear infections. The researchers found that those with a history of moderate to severe ear infections were 62 percent more likely to be obese.

Dr. David L. Katz, director of the Yale University School of Medicine Prevention Research Center, thinks that alteration in taste only plays a small part in the overall obesity epidemic in the United States.

"It certainly makes sense that variations in taste, due to many factors including a history of ear infections, could influence food preferences, total food intake and weight," he said.

However, despite variation in taste perception, variation in dietary preference, and variation in the history of ear infections, researchers have projections forecasting all but universal obesity among U.S .adults within several decades should current trends persist, Katz noted.

"So while the link between taste buds and vulnerability to obesity is worthy of further exploration, the simple fact is that the entire population is vulnerable to obesity," Katz said. "The major causes of the obesity epidemic reside in the 'obesigenic' environment, rather than on our tongues."

More information

For more on obesity, visit the U.S. National Library of Medicine.