The American Medical Association’s journal on pediatrics (JAMA Pediatrics) has published the second U.S. Government-funded study linking low-levels of fluoride exposure during fetal development to cognitive impairment. The observational study, entitled Association Between Maternal Fluoride Exposure During Pregnancy and IQ Scores in Offspring in Canada, was led by a team at York University in Ontario, Canada and looked at 512 mother-child pairs from six major Canadian cities. It was funded by the Canadian government and the U.S. National Institute of Environmental Health Science.
The scientists assessed fluoride exposure two ways. They measured fluoride in women’s urine samples during pregnancy. They also calculated fluoride consumption based on how much is in a city’s water supply and how much women recalled drinking. They found that a 1 mg per liter increase in concentration of fluoride in mothers’ urine was associated with a 4.5 point decrease in IQ among boys, though not girls. When the researchers measured fluoride exposure by examining the women’s fluid intake, they found lower IQs in both boys and girls: A 1 mg increase per day was associated with a 3.7-point IQ deficit among both genders.
Fluoride’s ability to damage the brain is one of the most active areas of fluoride research today. Over 400 studies have found that fluoride is a neurotoxin (a chemical that can damage the brain). This research includes:
- Over 200 animal studies showing that prolonged exposure to varying levels of fluoride can damage the brain, particularly when coupled with an iodine deficiency, or aluminum excess;
- 53 human studies linking moderately high fluoride exposures with reduced intelligence;
- 45 animal studies reporting that mice or rats ingesting fluoride have an impaired capacity to learn and/or remember;
- 12 studies (7 human, 5 animal) linking fluoride with neurobehavioral deficits (e.g., impaired visual-spatial organization);
- 3 human studies linking fluoride exposure with impaired fetal brain development.
- 3 Mother-Offspring studies linking certain levels of fluoride in the urine of pregnant women to reduced IQ in their offspring.
Based on this accumulating body of research, several prestigious reviews — including a report authored by the U.S. National Research Council, a meta-analysis published by a team of Harvard scientists, a review published in The Lancet, and a 2017 U.S.-funded 12-year study that found a link between fluoride in the urine of pregnant women and lower measures of intelligence in their children — have raised red flags about the potential for low levels of fluoride to harm brain development in some members of the population.