New study finds fluoride lowers IQ in children

Sat, 07 Oct 2017 19:39:24 +0000


There are signs that Americans are getting more stupid. See:

Here’s one reason why: fluoride in our drinking water.

In the United States, fluoride is added to drinking water at levels of 0.7–1.2 mg/L to promote dental health by preventing cavities. Fluoride is also found in varying degrees in salt, milk, and dental products, while fluoride supplementation has been recommended to prevent bone fractures.

A recent study by a team of 15 scientists found that pre-natal (in the womb) exposure to fluoride, at levels for the general population (i.e., common drinking water), is associated with lower IQs in children.

The 15 scientists are:

  • Morteza Bashash (senior author) and Howard Hu of Dalla Lana School of Public Health, University of Toronto, Ontario, Canada.
  • Deena Thomas, Brisa N. Sanchez, Karen E. Peterson, Adrienne S. Ettinger, Zhenzhen Zhang and Yun Liu, of University of Michigan School of Public Health.
  • E. Angeles Martinez-Mier of Indiana University School of Dentistry, Indiana University-Purdue University Indianapolis.
  • Niladri Basu of Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Quebec, Canada.
  • Robert Wright of Icahn School of Medicine at Mount Sinai, New York.
  • Lourdes Schnaas of Instituto Nacional de Perinatología, Mexico City, Mexico.
  • Adriana Mercado-García, Martha María Téllez-Rojo and Mauricio Hernández-Avila, of Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico.

Morteza Bashash, et al., published their findings in an article titled “Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6–12 Years of Age in Mexico,” in the peer-reviewed journal, Environmental Health Perspectives, vol. 125, issue 9 (September 2017).

Here is the article’s Abstract:

Background: Some evidence suggests that fluoride may be neurotoxic to children. Few of the epidemiologic studies have been longitudinal, had individual measures of fluoride exposure, addressed the impact of prenatal exposures or involved more than 100 participants.

Objective: Our aim was to estimate the association of prenatal exposure to fluoride with offspring neurocognitive development.

Methods: We studied participants from the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) project. An ion-selective electrode technique was used to measure fluoride in archived urine samples taken from mothers during pregnancy and from their children when 6–12 y old, adjusted for urinary creatinine and specific gravity, respectively. Child intelligence was measured by the General Cognitive Index (GCI) of the McCarthy Scales of Children’s Abilities at age 4 and full scale intelligence quotient (IQ) from the Wechsler Abbreviated Scale of Intelligence (WASI) at age 6–12.

Results: We had complete data on 299 mother–child pairs, of whom 287 and 211 had data for the GCI and IQ analyses, respectively. Mean (SD) values for urinary fluoride in all of the mothers (n=299) and children with available urine samples (n=211) were 0.90 (0.35) mg/L and 0.82 (0.38) mg/L, respectively. In multivariate models we found that an increase in maternal urine fluoride of 0.5mg/L (approximately the IQR) predicted 3.15 (95% CI: −5.42, −0.87) and 2.50 (95% CI −4.12, −0.59) lower offspring GCI and IQ scores, respectively.

Conclusions: In this study, higher prenatal fluoride exposure, in the general range of exposures reported for other general population samples of pregnant women and nonpregnant adults, was associated with lower scores on tests of cognitive function in the offspring at age 4 and 6–12 y.

Some other interesting points from the study:

  • The EPA (Environmental Protection Agency) had determined 4 mg/L to be the maximum contaminant level goal (MCLG) for the amount of fluoride in public drinking water. MCLG refers to a fluoride concentration at which no adverse health effects are expected.
  • In 2006, the EPA asked the National Research Council (NRC) to reevaluate the MCLG to determine if the standards were adequate to protect public health. NRC concluded that the MCLG of 4 mg/L should be lowered because it puts children at risk of developing severe enamel fluorosis and may be too high to prevent bone fractures caused by fluorosis. Moreover, there is experimental and epidemiologic evidence that fluoride may be neurotoxic.
  • At the time, the NRC found that healthy U.S. adults exposed to optimally fluoridated water had urinary fluoride concentrations ranging from 0.62 to 1.5 mg/L.
  • The study by Morteza Bashash, et al., was conducted on mother-child pairs in Mexico City, Mexico, where the natural water fluoride levels range from 0.15 to 1.38 mg/L., which is much lower than the U.S. maximum contaminant level goal of 4 mg/L. In addition, the participants in the study have also been exposed to fluoridated salt (at 250 ppm).
  • Effect of prenatal exposure to fluoride on the child’s IQ score is 2.5 points lower with a 0.5 mg/L increase in prenatal exposure.
  • The findings of Bashash, et al., are “consistent with the ecological studies suggesting children who live in areas with high fluoride exposure (ranging from 0.88 to 11.0 mg/L fluoride in water, when reported) have lower IQ scores than those who live in low-exposure or control areas (ranging from 0.20 to 1.0 mg/L fluoride in water)” and with other recent studies.

Bashash, et al.‘s conclusion is that:

“[Whereas] Community water and salt fluoridation, and fluoride toothpaste use, substantially reduces the prevalence and incidence of dental caries (Jones et al. 2005) and is acknowledged as a public health success story . . . However, our findings, combined with evidence from existing animal and human studies, reinforce the need for additional research on potential adverse effects of fluoride, particularly in pregnant women and children, and to ensure that the benefits of population-level fluoride supplementation outweigh any potential risks.”


In addition to lowering intelligence, years ago it was found that fluoride may also lead to an early onset of puberty in girls.

In a Dec. 4, 2008 article, Dr. Mercola explains that:

  • The pineal gland is a small gland located between the two hemispheres of the brain, which regulates the production of the hormone melatonin.
  • Melatonin is a hormone that helps regulate the onset of puberty and helps protect the body from cell damage caused by free radicals.
  • Dr. Jennifer Luke from the University of Surrey in England found that fluoride accumulates in the pineal gland, and that experimental animals treated with fluoride had lower levels of circulating melatonin, resulting in an earlier onset of puberty in the fluoride-treated female animals.
  • In addition to other environmental chemicals — PCBs and endocrine-disrupting chemicals of BPA, phthalates and PFOA (Teflon) — fluoride may contribute to U.S. girls reaching puberty at younger ages than ever before. In the 1990s, breast development — the first sign of puberty in girls — at age 8 was considered an abnormal event that should be investigated by an endocrinologist. A study in 1997 found that almost half of African American and 15% of white girls had begun breast development by age 8. Some studies have even found girls as young as 2 who are starting sexual development.


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