NTP report: Higher fluoride levels linked to lower IQ in children

NTP report: Higher fluoride levels linked to lower IQ in children | Image Credit: © Brian Jackson - © Brian Jackson - stock.adobe.com.

According to a report from the National Toxicology Program (NTP), which is part of the Department of Health and Human Services, higher levels of fluoride exposure, such as drinking water that contains more than 1.5 milligrams of fluoride per liter, are associated with lower IQ in children. These findings were published with "moderate confidence" in the scientific evidence that demonstrated the association, according to NTP.¹

The report, published August 21, 2024, summarized a review of studies conducted in Canada, China, Iran, India, Pakistan, and Mexico, seeking to examine the association between fluoride exposure and neurodevelopment and cognition.^1,2

The report, according to The Associated Press (AP), did not try to quantify how many IQ points could be lost at different levels of higher exposure. The AP noted that federal health officials have recommended a fluoridation level of 0.7 milligrams per liter since 2015. The World Health Organization has set a safe limit for fluoride in drinking water of 1.5.²

"The NTP review was designed to evaluate total fluoride exposure from all sources and was not designed to evaluate the health effects of fluoridated drinking water alone," findings of the report read in an abstract from the NTP. "It is important to note, however, that there were insufficient data to determine if the low fluoride level of 0.7 mg/L currently recommended for [United States] community water supplies has a negative effect on children’s IQ," the findings read.¹

In a statement published on August 26, 2024, the American Fluoridation Society (AFS) stated the report had removed an original assertion that fluoride is a "presumed" neurodevelopmental hazard. AFS also highlighted that the 1.5 milligrams per liter linked to lower IQ scores in the report is more than double the fluoride level that is used for water fluoridation in North America.³

Johnny Johnson, president of AFS stated health officials and parents should "take care" in interpreting the NTP report, stating, "Even the NTP report states that its finding does not apply to water fluoridation."³

Approximately 80 years ago, scientists discovered that people who had water supplies that contained more fluoride also had fewer cavities, which resulted in a push to get more Americans to use fluoride for better dental health, stated the AP. According to the AP article, the American Dental Association had been critical of earlier versions of the NTP analysis.²

The AFS stated that the safety of fluoridated water is backed by more than 75 years of research and experience, and that fluoridation is recommended by the American Academy of Pediatrics, American Dental Association, and the American Academy of Family Physicians. AFS also referenced a statistic published by the Centers for Disease Control and Prevention that stated fluoridation reduces tooth decay by 25% in children and adults.^3,4

NTP stated in the report that concern has grown that some pregnant women and children could be getting more fluoride than they need because of it being included in several sources such as treated public water, water-added foods and beverages, teas, toothpaste, floss, and mouthwash. These combined total intakes could exceed safe amounts, stated NTP.¹

After publishing the aforementioned findings, the NTP stated "More research is needed to better understand if there are health risks associated with low fluoride exposures. This NTP monograph may provide important information to regulatory agencies that set standards for the safe use of fluoride. It does not, and was not intended to, assess the benefits of fluoride."¹

References:

1. NTP monograph on the state of the science concerning fluoride exposure and neurodevelopment and cognition: a systematic review. National Toxicology Program. 2024. Research Triangle Park, NC: National Toxicology Program. NTP Monograph 08. https://doi.org/10.22427/NTP-MGRAPH-8
2. Stobe M. US government report says fluoride at twice the recommended limit is linked to lower IQ in kids. AP News. August 21, 2024. Accessed August 26, 2024. https://apnews.com/article/fluoride-water-brain-neurology-iq-0a671d2de3b386947e2bd5a661f437a5
3. Fluoride report walks back its original findings. American Fluoridation Society. Accessed August 26, 2024. https://www.prnewswire.com/news-releases/fluoride-report-walks-back-its-original-findings-302230512.html
4. CDC scientific statement on community water fluoridation. CDC. May 15, 2024. Accessed August 26, 2024. https://www.cdc.gov/fluoridation/about/statement-on-the-evidence-supporting-the-safety-and-effectiveness-of-community-water-fluoridation.html