Fluoride — A Little Bit at the Wrong Time Is Devastating

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Story at-a-glance -

  • Higher exposure to fluoride while in utero is associated with lower scores on tests of cognitive function in childhood
  • Women with higher levels of fluoride in their urine during pregnancy were more likely to have children with lower intelligence
  • Each 0.5 milligram per liter increase in pregnant women’s fluoride levels was associated with a reduction of 3.15 and 2.5 points on the children’s cognitive and intelligence test scores, respectively

By Dr. Mercola

In the U.S., two-thirds of Americans' tap water contains fluoride, which is added under the guise of preventing cavities. Water fluoridation continues to occur in the majority of the U.S. even as research stacks up that fluoride is a neurotoxin that can harm brain function. A study of Mexican women and children is among the latest to raise concern, showing that higher exposure to fluoride while in utero is associated with lower scores on tests of cognitive function in childhood, both at the age of 4 and 6 to 12 years.1

The study involved nearly 300 pairs of women and their babies. Mexico does not fluoridate their drinking water, but the study participants were exposed to fluoride via fluoridated salt and varying levels of naturally occurring fluoride in drinking water. While previous studies have used measurements of fluoride levels in drinking water to estimate a population's exposure, the featured study used urine samples — in both the mothers and their children — to determine fluoride exposure.

The researchers then compared fluoride levels with each child's intelligence, assessed using the General Cognitive Index (GCI) of the McCarthy Scales of Children's Abilities at age 4 and again between the ages of 6 and 12 years using the Wechsler Abbreviated Scale of Intelligence (WASI).2

Higher Prenatal Exposure to Fluoride Linked to Lower Intelligence

While the children's fluoride levels at ages 4 and 6 to 12 were not associated with their intelligence, the study found that exposure that occurs prenatally was linked to lower intelligence scores. In fact, women with higher levels of fluoride in their urine during pregnancy were more likely to have children with lower intelligence.

Specifically, each 0.5 milligram per liter increase in pregnant women's fluoride levels was associated with a reduction of 3.15 and 2.5 points on the children's GCI and WASI scores, respectively. Lead researcher Dr. Howard Hu, of the Dalla Lana School of Public Health at the University of Toronto in Canada, said in a news release:3

"Our study shows that the growing fetal nervous system may be adversely affected by higher levels of fluoride exposure. It also suggests that the prenatal nervous system may be more sensitive to fluoride compared to that of school-aged children."

The findings are groundbreaking, as the study, which spanned 12 years and received funding from the U.S. National Institutes of Health (NIH), is one of the first and largest studies looking into this topic. As noted by Paul Connett, Ph.D., toxicologist, environmental chemist and former director of the Fluoride Action Network (FAN) in the video commentary below (while retiring and handing over the director's position to his son Michael, Connett remains very active in the organization):

"This vindicates our work … since 1996. My major concern has been the effect of fluoride on the brain … A variety of studies … have indicated that in communities with higher levels of fluoride, children have lower IQ. It's always been a question of whether that was exposure during pregnancy in utero or whether the exposure was in the early years of childhood. This study points to in utero exposure.

This should spell the end of fluoridation worldwide. How can you possibly continue to expose millions of pregnant women and children to a known neurotoxic substance? Now we know that there's a relationship between how much fluoride a woman is exposed to in pregnancy and the IQ of the children that are born. This is totally unacceptable."

Despite the damning evidence, the American Dental Association (ADA) continues to stand their ground, stating, "The ADA continues to endorse fluoridation of public water as the most effective public health measure to prevent tooth decay."4 They tried to downplay the results by saying no conclusions could be drawn about U.S. water fluoridation because it's unknown whether the participants were exposed to fluoride via water, salt or both.

But as noted by Connett, "This makes no sense. It is irrelevant whether the Mexican women got their fluoride from fluoridated salt, fluoride in drinking water or from fluoridated dental products." The mean level of fluoride in the urine of the mothers included in the study was 0.9 mg/L. In the U.S. 75 percent of the population's drinking water is fluoridated, and according to Hu, the levels of fluoride found in Mexican mothers is unlikely to be significantly different from those found in American women.

Fluoride Previously Known to Harm Brain, Nervous System Development

More than 300 studies have shown fluoride's toxic effects on the brain,5 including 2006 National Research Council review that suggested fluoride exposure may be associated with brain damage, endocrine system disruption and bone cancer.6 In 2012, Harvard researchers also revealed that children living in high-fluoride areas had significantly lower IQ scores than those who lived in low-fluoride areas7 and suggested high fluoride exposure may have an adverse effect on children's neurodevelopment.

Then, in 2014, a review in Lancet Neurology classified fluoride as one of only 11 chemicals "known to cause developmental neurotoxicity in human beings,"8 alongside other known neurotoxins such as lead, methylmercury, arsenic and toluene. Among the proposed mechanisms of harm, studies have shown fluoride can:9

Interfere with basic functions of nerve cells in the brain

Reduce nicotinic acetylcholine receptors

Reduce lipid content in the brain

Damage the pineal gland through fluoride accumulation

Impair antioxidant defense systems

Damage the hippocampus

Damage purkinje cells

Increase uptake of aluminum, which has neurotoxic effects

Encourage formation of beta-amyloid plaques (the classic brain abnormality in Alzheimer's disease)

Exacerbate lesions induced by iodine deficiency

Increase manganese absorption, which has also been linked to lower IQ in children

Impair thyroid function, which can also affect brain development

Most US Kids Have Fluoride-Damaged Teeth

According to research presented at the April 2017 National Oral Health Conference in Albuquerque, New Mexico, 57 percent of youth between the ages of 6 and 19 years have dental fluorosis, a condition in which your tooth enamel becomes progressively discolored and mottled, according to data from 2011 to 2012.10 The statistic represents an increase from 37 percent reported from 1999 to 2004. Further, the author stated, "There was a significant increase in caries experience … ."

When FAN researchers analyzed the same set of data, they found "the 2011-2012 NHANES survey found dental fluorosis in 58.3 percent of the surveyed adolescents, including an astonishing 21.2 percent with moderate fluorosis and 2 percent with severe."11 Research has found impairment in cognitive abilities among children with fluorosis (even mild fluorosis) compared to children with no fluorosis. And some studies have even found that children with higher levels of fluorosis have increased rates of cavities.12,13

In stark contrast, when fluoridation was first started in the U.S. in 1945, it was promised that only 10 percent of people would suffer from mild dental fluorosis.14 In light of the latest findings in the featured study, keep in mind that if children live in areas with high enough fluoride levels in their water to cause dental fluorosis, their mothers also were likely exposed to similar levels of fluoridated water during pregnancy, posing brain risks as well. As FAN noted:15

"The human placenta does not prevent the passage of fluoride from a pregnant mother's bloodstream to the fetus. As a result, a fetus can be harmed by fluoride ingested pregnancy.

Based on research from China, the fetal brain is one of the organs susceptible to fluoride poisoning … three Chinese studies have investigated fluoride's effect on the fetal brain and each has found evidence of significant neurological damage, including neuronal degeneration and reduced levels of neurotransmitters such as norepinephrine."

How Much Fluoride Is in Your Water?

The vast majority (97 percent) of Western Europe has rejected water fluoridation. In fact, most countries fluoridate neither their water nor their salt (but according to the World Health Organization, tooth decay in 12-year-olds is coming down as fast, if not faster, in nonfluoridated countries as it is in fluoridated countries16). In contrast, in the U.S. 200 million Americans live in areas where water is fluoridated.

As for how much fluoride is in your drinking water, in 2011 the U.S. Department of Health and Human Services announced plans to lower the recommended level of fluoride in drinking water for the first time in 50 years. Effective in 2015, the level of fluoride in drinking water was reduced to 0.7 mg/L from a previously recommended range of between 0.7 to 1.2 mg/L. If you live in the U.S. and want to know fluoride levels in your water, the Environmental Working Group's (EWG) Tap Water Database can help.17

This is important for everyone, but pregnant women and households mixing formula for babies should take extra care to consume fluoride-free water. EWG notes, "Even fluoride levels of 0.7 ppm, the amount of fluoride in drinking water recommended by the U.S. Public Health Service, can result in too much fluoride for bottle-fed babies."

EWG recommends that caregivers mix baby formula with fluoride-free water. The National Toxicology Program is investigating the potential for low doses of fluoride to alter thyroid function and childhood brain development."18

Unfortunately, fluoride is a very small molecule, making it tremendously difficult to filter out once added to your water supply. Any simple countertop carbon filter, like Brita, will not remove it. If you have a house water carbon filtration system that has a large volume of carbon, then it may reduce the fluoride as fluoride removal is in direct proportion to the amount of fluoride and the time it's in contact with the media. It's just not going to get it all. Among the more effective filtering systems for fluoride removal are:

  • Reverse osmosis (RO). The drawback is that it will remove many valuable minerals and trace elements as well. RO systems also need frequent cleaning to avoid bacterial growth. So, use a tankless RO system with a compressor
  • Water distillation which, like RO, gets everything out, including beneficial minerals. You then need to restructure the water
  • Bone char filters and biochar. We're currently in the process of developing a filter that combines biochar with activated charcoal

Clearly, the simplest, most effective, most cost-effective strategy is to not put fluoride in the water to begin with. To learn more about fluoride and how you can help end this harmful practice, I highly recommend getting a copy of Connett's book, "The Case Against Fluoride." You can also download my free report on water fluoridation for more information on the bad science and political agendas that got this toxic chemical in your drinking water.

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