In a previous article, we discussed what fluoride is and how it helps protect teeth from decay. But while fluoride is widely recognized by public health experts as a safe and effective tool, it’s also a subject that has sparked confusion and concern among some people.
At Lakes Regional Healthcare, we take your concerns seriously. Questions about what goes into your drinking water deserve honest, evidence-based answers. In this article, we’ll address the most common questions and claims about fluoride – including safety, toxicity, and its effects on children – and explain what decades of research show.
Question/Claim #1: Fluoride lowers children’s IQ and harms children’s brain development.
This claim is based largely on a meta-analysis of 74 epidemiological studies conducted primarily in areas of China, India, and Iran, where natural fluoride levels are much higher than U.S. standards – sometimes up to 10-12 mg/L (over 10 times the level in U.S. drinking water). This analysis was published in the Journal of the American Medical Association Pediatrics on January 6, 2025. Of the 74 studies, 22 were rated as high quality (low risk of bias) and 52 were rated as low quality (high risk of bias). None of the studies were conducted in the United States. These studies measured fluoride in drinking water and in urine. They concluded, with moderate confidence, that higher levels of fluoride in drinking water (>1.5 mg/L) are associated with lower IQ in children. There was no association at less than 1.5 mg/L (and consequently, no association with lower IQ at the level of 0.7 mg/L currently recommended in the U.S. fluoridated water supply). However, for fluoride measured in urine, there was a higher association between lower IQ and fluoride exposure in all measurement categories (less than 4 mg/L, less than 2 mg/L, and less than 1.5 mg/L). The measurement of fluoride in urine is an estimate of total fluoride exposure from all sources such as drinking water, food, dental products, pharmaceuticals, and more. The analysis found that for every 1 mg/L increase in urinary fluoride, there is a decrease of 1.63 IQ points in children.
Recent U.S.-based studies with more rigorous methodology, like those conducted by the Centers for Disease Control and Prevention (CDC) and University of Iowa, show no impact on IQ or brain development at 0.7 mg/L, like the drinking water fluoridation studies analyzed in the meta-analysis.
Furthermore, studies from New Zealand and Sweden have shown the IQ scores of teens and adults living in fluoridated communities during infancy and childhood were no different than the scores of people who lived in communities without fluoridated water. These two studies were unique because they followed participants over time and tracked IQs and other possible effects, well into adulthood.
There are also studies that show higher cognitive scores among those exposed to fluoride. A large Australian study in 2022 followed boys and girls with different lifetime fluoride exposures from birth to age 5. The level of fluoride in the water used in this study was comparable to that in the U.S. and assessed the children’s emotional and behavioral development until they reached age 18. The study concluded exposure to fluoridated water during the first five years of life was not associated with altered measure of child emotional and behavioral or executive functioning.
Any study of IQ differences must consider the many factors that can affect intelligence scores, some of which include breastfeeding, nutrition, and parents’ IQ. Also, an association indicates a connection between fluoride and lower IQ; it does not prove a cause and effect.
Overall, the American Academy of Pediatrics, World Health Organization, and CDC all support water fluoridation and have found no link to cognitive or neurological harm at the levels used in the U.S.
Question/Claim #2: Europe doesn’t fluoridate water, so why should we?
It’s true many European countries don’t fluoridate water, but that’s not because they oppose fluoride. Water fluoridation is not feasible or cost-effective in many regions of the world, especially rural areas. For example, in France and Switzerland, water fluoridation is logistically difficult because of the terrain and because there are tens of thousands of separate sources for drinking water. Instead of adding fluoride to water, they use other methods:
- Fluoridated salt and milk are widely used in parts of Europe.
- Many countries have natural fluoride in their water at or near optimal levels.
- Universal dental care systems provide preventive fluoride treatments.
When you compare cavity rates between fluoridated and non-fluoridated countries, you find that countries with other fluoride delivery systems achieve similar benefits, because it’s not about the source. It’s about consistent fluoride exposure.
Question/Claim #3: Fluoride is toxic. Why would we put it in our water?
The dose of fluoride makes the poison. Virtually anything – even water or oxygen – can be toxic in high amounts. What matters is the amount, and at the levels used in community water systems (0.7 milligrams per liter), fluoride is not toxic.
Scientific bodies worldwide, including the American Dental Association (ADA), CDC, and World Health Organization (WHO), all endorse water fluoridation as safe. The fluoride used in public water supplies is highly diluted, well below any harmful threshold.
Research says toxic effects (such as skeletal fluorosis) occur only at very high levels of exposure over long periods – hundreds of times greater than those in U.S. drinking water.
Question/Claim #4: Fluoride causes cancer, especially bone cancer.
This concern arose from early studies in the 1990s that suggested a potential link between high fluoride exposure and osteosarcoma (a rare bone cancer) in young males. However, subsequent research – including large-scale population studies – found no consistent or credible link.
The National Cancer Institute (NCI), along with the American Cancer Society, have reviewed the data and concluded there is no association between fluoridated water and cancer risk. For example, data from a 2011 Harvard study and a comprehensive review by the National Research Council found no evidence to support a cancer link at fluoridation levels in the U.S.
Question/Claim #5: Fluoride is unsafe for babies and pregnant women.
Fluoride is safe for both pregnant women and infants. While infant formula can be mixed with fluoridated water, parents who are concerned about dental fluorosis (cosmetic white spots on developing teeth) can alternate between fluoridated water and low-fluoridated bottled water if they wish, but it’s not medically necessary.
According to the American Academy of Pediatrics:
- Fluoride at optimal levels does not harm infant health.
- For babies who are breastfed or formula-fed using tap water, no additional fluoride supplements are needed unless directed by a pediatrician.
Pregnant women can safely consume fluoridated water. Fluoride helps protect their teeth during pregnancy – a time when women are most prone to dental issues.
Question/Claim #6: We don’t know enough to say fluoride is safe.
Fluoride is one of the most studied substances in public health history. More than 6,800 peer-reviewed studies have been published on fluoride and its effects – spanning toxicology, epidemiology, neuroscience, and dentistry.
In 2006, the National Research Council (NRC) completed an exhaustive review of fluoride in drinking water and found that levels above 2 mg/L could pose a health risk – but again, U.S. fluoridation levels are far lower (0.7 mg/L).
In 2023, the U.S. National Toxicology Program (NTP) released a long-awaited review of fluoride research. Their conclusion? There is inconsistent and low-quality evidence of any harm at standard fluoridation levels.
Question/Claim #7: Fluoride causes dental fluorosis.
Dental fluorosis is the only confirmed side effect of fluoride – and it’s mild and cosmetic in almost all cases in the U.S. It typically appears as faint white lines or spots on teeth and does not affect function or cause pain.
It occurs when children under age 8 consume too much fluoride during tooth development, often due to swallowing toothpaste. Here’s how to minimize the risk:
- Use a pea-sized amount of fluoride toothpaste for kids ages 3-6.
- Supervise brushing to avoid swallowing toothpaste.
- Do not use fluoride mouth rinses for children under 6 unless recommended by a dentist.
Fluorosis is easily prevented, and much less harmful than cavities, which are still far more common and costly.
Final Thoughts
The evidence is clear: fluoride is safe, effective, and one of the most powerful tools to fight tooth decay – a condition that affects nearly every American at some point in their life.
While it’s natural and important to ask questions, it’s important to also look at the data critically and objectively. At Lakes Regional Healthcare, we support science-based public health practices that protect everyone. We encourage you to stay curious, seek trusted sources, and ask questions. That’s how public trust grows.
