Proponents and opponents of fluoride in public drinking water debated before the House Conservation and Environment Committee Monday.

The federal Centers for Disease Control and Prevention lists water fluoridation as among the top 10 public health achievements of the last century, but in the past decade opposition to water fluoridation has increased nationwide.

Water fluoridation reduces dental decay, health officials said.

“Water fluoridation is … the adjustment of this naturally occurring mineral in the water that has been found through years of research to reduce decay by 20-40 percent in populations,” Suzanne Hayes, director for oral health services at the Tennessee Department of Health, said, adding for every dollar invested in fluoridation, communities save $38 in dental treatment.

However, opponents claim fluoride can cause severe health symptoms, from cancer to thyroid disease and bone fractures. Dan Stockin with the Lillie Center, a Brentwood-based company offering public training on health issues, said a CDC study released in August shows that 32 percent of children show signs of dental fluorosis — a discoloring of teeth caused by too much fluoride.

Cavities, Stockin told the House committee, can be avoided by access to dental care, promotion of dental health, and the reduction of sugary food.

“The lack of fluoride does not cause cavities. Too many sugary foods and the lack of dental health is what causes cavities,” Stockin said.

Stockin called fluoride “a cumulative poison” that works primarily through topical mechanisms and, when digested, builds up in the human body over time, which can cause severe health effects.

Health officials countered that drinking fluoridated water has been proven safe by more than 60 years of scientific studies.

“This proven public health measure has resulted in remarkable declines in tooth decay regardless of age, race, sex, socioeconomic status or demographic,” Tennessee Health Commissioner Dr. Kenneth Robinson wrote in a letter dated Jan. 5 addressing legislators.

Water fluoridation is a decision made on the local level. Committee chair Rep. Gary Odom (D-Nashville) said he knew of several utility districts in Tennessee debating the issue whether to stop or start the practice.

Tennessee’s first local utility district to start fluoridation was Milan in 1951. Now 335 systems serving between 4.5 and 5 million people add fluoride to their water supplies, and 145 mostly small utility districts serving between 300,000 and 350,000 Tennesseans do not add it.

Tom Reeves, professional engineer with the State Health Department who supports water fluoridation, said about half of the fluoride consumed comes from other sources than water, such as tea or grape juice — a fact that health officials take into account when assessing the necessary amount of water additives.

Even some bottled waters include fluoride, Reeves said, because some municipalities are making money off bottling water.

But consumers can take fluoride out of their water supply through water filters using distillation or reverse osmosis.

“As a general rule — but there are some exceptions — units that are installed at the water fossils do not remove fluoride, units installed under the sink will,” Reeves said.

Several health organizations signed the health commissioner’s letter to legislators, including representatives from the Tennessee Dental Association, the Tennessee Dental Hygienists’ Association, the Tennessee Dietetic Association, the Tennessee Commission on Children and Youth, the Tennessee Chapter of the American Academy of Pediatrics, the Bureau of TennCare, the Pan-Tennessee Dental Association, the Interfaith Dental Clinic, the Tennessee Medical Association, and the Tennessee Farm Bureau Federation.