A Rutgers pediatric dental expert discusses why fluoride in U.S. drinking water isn't a concern
A just-released study of the effects of fluoride on populations outside of the United States is fueling the debate on the use of this naturally occurring mineral that strengthens tooth enamel in tap water, raising unnecessary concern, said Mary Beth Giacona, an assistant professor of pediatric dentistry at Rutgers School of Dental Medicine.
Giacona discusses the issues in the debate about water fluoridation.
What is the purpose of adding fluoride to water supplies?
Cavities occur when bacteria in the mouth metabolize carbohydrates and secrete acids that create holes (cavities) in teeth. Fluoride chemically binds to enamel and physically makes it harder and thus more resistant to tooth decay.
When people drink fluoridated water, their teeth will absorb some of that fluoride. When young children drink fluoridated water, that fluoride gets incorporated into the enamel of unerupted teeth that are still forming. This can help protect those permanent teeth from cavities before they even grow into the mouth.
Most people proclaiming the dangers of fluoride are referring to studies that were done outside the United States, in areas where naturally high levels of fluoride are present in the water people drink.
Mary Beth Giacona
Assistant Professor, Pediatric Dentistry, Rutgers School of Dental Medicine
What are the potential harms of water fluoridation?
Young children who ingest too much fluoride when the enamel on their permanent teeth is still forming can end up with fluorosis. Fluorosis occurs when too much fluoride is absorbed into teeth that are still forming and the excess fluoride causes discoloration of the enamel, usually white spots but sometimes brown spots in cases with very high levels of fluoride.
Should people in the U.S. be concerned about reports linking fluoridated water to lower IQs and other neurological disorders?
Most people proclaiming the dangers of fluoride are referring to studies that were done outside the United States, in areas where naturally high levels of fluoride are present in the water people drink. The levels of fluoride in these studies are significantly higher than levels intentionally put into community water supplies. Here in the United States, water supplies are fluoridated at a maximum of 0.7ppm fluoride. That is even lower than what the World Health Organization recommends: a maximum of 1.5ppm fluoride.
Experts, including scientists from the Centers for Disease Control and Prevention, are critical of the findings of the studies linking fluoride to lower IQ and other neurological disorders. The studies were not conducted with rigorous methods and the evidence is low quality.
How can we be sure that drinking fluoridated water is safe?
Scientists and public health officials have worked hard to ensure that water supplies in the United States are optimally fluoridated. This optimal level is the therapeutic index. This is the "just right" amount of something (including medications): Too little won't have the desired effect, but too much can cause unwanted side effects.
Decades of research have led public health officials to determine the optimal amount of fluoride to add to water supplies, helping to prevent tooth decay without causing fluorosis or other problems. This optimal amount has changed over the years. When the first fluoridation efforts took place in the 1940s and 1950s, higher levels of fluoride were added than what goes into U.S. water supplies today. Now that fluoridated toothpaste is widely used and people are ingesting fluoride from other sources, such as processed foods, the amount of fluoride added to water has been reduced so that people can continue to receive a therapeutic dose.
Decades of research have led public health officials to determine the optimal amount of fluoride to add to water supplies, helping to prevent tooth decay without causing fluorosis or other problems.
Mary Beth Giacona
Public water supplies in the United States have several chemicals added to them to ensure that the water is safe to drink. Each of those additives is carefully monitored to ensure that the appropriate level, or therapeutic dose, is achieved.
What might happen if we stop adding fluoride to drinking water?
Water fluoridation has been shown to reduce tooth decay by 20% to 40%. New Jersey has very low rates of water fluoridation; only 16% of residents have fluoridated water supplies. A recent survey of children throughout New Jersey found that they had higher rates of untreated tooth decay than the national average. New Jersey residents also have higher rates of autism and Alzheimer's disease than the national average, debunking the theory that these neurological disorders can be linked to fluoridated water.
Published data from communities that stopped water fluoridation show an increase in tooth decay, especially in vulnerable low-income young children. This is not only detrimental to those children, but it also burdens our health system with the cost of treating those cavities. Water fluoridation is very inexpensive, costing about $1 per person per year.
Water fluoridation is a safe and effective way to prevent tooth decay that can benefit the entire population, regardless of family income or socioeconomic status. This is why the CDC calls water fluoridation one of the 10 greatest public health achievements of the 20th century.
