Nov. 27 (UPI) -- For American children, tap water's health benefits come with risks.
New research shows children and adolescents in the United States who avoid tap water are more likely to have tooth decay. The data also shows young people who avoid tap have lower levels of lead in their blood.
Most municipal water in the U.S. is fluoridated, which numerous studies have proven prevents cavities. However, aging infrastructure presents risks, including elevated lead levels in drinking water.
The lead crisis in Flint, Michigan, is an extreme example of a problem that's fairly common in the United States. Studies show 5,300 water systems in the U.S. are in violation of the EPA's lead and copper limits.
When researchers at the University of North Carolina examined blood and dental data of some 16,000 children and adolescents -- collected as part of the National Health and Nutrition Examination Survey -- they found children who said they didn't drink tap water were more likely to have had at least one cavity.
Those same children were also less likely to have elevated lead levels, defined as more than three micrograms in a deciliter of blood.
Researchers found 3 percent of those surveyed had elevated lead levels in their blood. Nearly 50 percent had tooth decay.
"Elevated blood lead levels affect only a small minority of children, but the health consequences are profound and permanent," UNC researcher Anne E. Sanders said in a news release. "On the other hand, tooth decay affects one in every two children, and its consequences, such as toothache, are immediate and costly to treat."
Sanders and her colleagues published their findings in the American Journal of Preventive Medicine.
"Our study draws attention to a critical trade-off for parents: children who drink tap water are more likely to have elevated blood lead levels, yet children who avoid tap water are more likely to have tooth decay," researcher Gary D. Slade said. "Community water fluoridation benefits all people, irrespective of their income or ability to obtain routine dental care. Yet we jeopardize this public good when people have any reason to believe their drinking water is unsafe."