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Does Fluoride In Drinking Water Cause Brain Damage? (Neurotoxicity)

Fluoride is considered a colorless inorganic anion of the chemical fluorine and is commonly used as an additive in drinking water to improve dental health.  Adding fluoride to tap water is a proven method for decreasing rates of tooth decay and cavities.  The United States Center for Disease Control markets fluoridation of tap water as being among the 10 greatest public health achievements of the 20th century.

The recommended daily intake of water for men in the United States is 3 liters, which contains an estimated 2.1 mg of fluoride.  For adults, fluoride ingestion of 10 mg per day is considered the maximum safe limit, anything beyond this amount is considered hazardous to health.  To put things in perspective, 10 mg of fluoride could be attained by drinking approximately 14 liters of tap water – more than enough water to get you through the day.

The maximum daily recommended fluoride intake for infants and children ranges from 0.7 mg to 2.2 mg – considerably less than adults.  Assuming an adult were drinking 3 liters of water per day, they’d be ingesting just under the “safe” daily maximum fluoride intake for children.  Despite proponents of water fluoridation (e.g. the American Dental Association) noting its cost-effectiveness for the prevention of tooth decay, other organizations (e.g. the EPA) suggest that fluoride may act as a neurotoxin, impairing brain development.

Is the fluoride in drinking water neurotoxic to human brains?

The intention of water fluoridation is to prevent tooth decay, especially among children that fail to receive adequate dental care.  It is a safe and cost-effective way to reduce cavities and is considered one of the major health innovations of the 20th century.  That said, some believe that there is significant neurotoxic risk associated with government mandated fluoride concentrations in drinking water.

Until 2015 when the government revised their fluoride recommendations, some areas of the country had higher levels of fluoride in drinking water than others.  If you lived in a cooler region, you may have had water fluoridation around 1.2 ppm, whereas if you lived in a warmer area, the fluoride content was lower at around 0.7 ppm.  These days, the fluoride content should be around 0.7 ppm – regardless of your location.

This revision was made not only as a result of increases in rates of dental fluorosis – a condition associated with white splotches on teeth, but also due to the fact that high fluoride may be toxic to the brain.  As a result of potential neurotoxicity in children and infants in highly fluoridated regions, experts such as Philippe Grandjean recommended reducing fluoride to an average of 0.7 ppm.

Many areas of the United States such as Massachusetts had fluoride levels exceeding 1.0 ppm (on average).  Although fluoride has been accepted as non-toxic at government mandated amounts, there isn’t sufficient research to really understand whether fluoride could be neurotoxic, even at low levels such as 0.7 ppm.  Until more research is done, polarizing claims that fluoride is definitively safe vs. completely unsafe for the human brain cannot be supported.

The recent reduction from 0.7 ppm to 1.0 ppm may contribute to simultaneous reductions in fluoride-induced neurotoxicity and/or brain damage.  That said, even small amounts such as 0.7 ppm may be detrimental to brain performance.  To put things in perspective, past experts thought that: lead (in gasoline), mercury, pesticides, asbestos, etc. – were fairly safe; similars tale could one day be told of fluoride as more human research surfaces.

Fluoride’s Effects on Human Brains (Research)

There are several human studies attempting to investigate fluoride’s effects on the brain.  There is some evidence to suggest that high fluoride exposure may be neurotoxic.  Some studies suggest that fluoride exposure has deleterious effects on the neurodevelopment of children.

In fact, some researchers have gone as far as to imply that high fluoride exposure may lower intelligence by up to 7 IQ points.  Understand that there are several limitations associated with the research of fluoride’s effect on human brains.  Despite limitations associated with the research, the findings in the studies listed below warrant further investigation.

2015: Previous evidence suggests that fluoride can impair neurodevelopment of children.  It is hypothesized that fluoridation of water promotes neurotoxicity within the brain, which can detrimentally affect neurodevelopment.  For this study, researchers recruited a total of 51 first-graders living in China.

Researchers initially measured fluoride concentrations within urine after a night with no exposure.  They also measured levels of fluoride within well-water and documented past fluoride exposure (as evidenced by dental fluorosis).  In addition, an array of neurodevelopment tests were administered to the children including the Wide Range Assessment of Memory, Learning (WRAML) and the Wechsler Intelligence Scale for Children (WISC), a finger tapping and grooved pegboard test.

Results indicated that the greater degree of dental fluorosis, the poorer the performance on intelligence tests.  Differences were most apparent in digit span assessments included within the Wechsler Intelligence Scale for Children.  Children with high fluorosis had worse scores on digit span tests by an average of 4.28 points.

Although a pilot study, this research suggests that fluoridation of drinking water can facilitate neurodevelopmental toxicity.  Authors note that further analysis of fluoride dose on neurotoxicity in children is warranted.  This study provides some evidence to suggest that fluoridation of water may be harmful to the human brain, especially among children.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/25446012

2012: A study published in 2012 noted that fluoride is a neurotoxin in animal models and can be neurotoxic to adult humans in high doses.  Knowing the neurotoxic potential of fluoride, researchers analyzed fluoride’s impact on the brains of children.  Researchers conducted a systematic review and meta-analysis of all published studies that sought to determine whether fluoride exposure in children causes neurodevelopmental delays.

Authors scoured various medical databases for all studies published through 2011.  Due to the lack of fluoride research in humans, researchers were only able to find a total of 27 epidemiological studies.  These studies compared fluoride exposure with intelligence quotient (IQ) scores and/or other aspects of cognitive function.

For this review, researchers used random-effects models and approximated average differences between those exposed to fluoride and non-exposed individuals.  Results indicated that individuals living in high-fluoride areas had significantly lower IQ scores than individuals living in low fluoride areas.  In other words, the authors implied an inverse relationship between fluoride exposure and intelligence among children.

The reduction in IQ as a result of fluoride exposure was suggested to be a weighted mean difference of “-0.45” – which has been suggested to equal 7 IQ points based on standard scoring.  Authors noted the possibility that high fluoride exposure could impair neurodevelopment of children, causing lower IQ scores.  Although the IQ difference was considered modest by most interpretations, further research is warranted to fully understand the impact of water fluoridation on the neurodevelopment of children.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/22820538

2007: A study published in 2007 aimed to investigate the impact of both arsenic and fluoride exposure on neurodevelopment and growth of children.  For the study, researchers recruited 720 children aged 8 to 12 living in the Shanxi province of China.  The children were then sorted into groups including: a medium and high arsenic group, a high fluoride and low arsenic group, and a low fluoride and low arsenic (control group),

Researchers administered standard IQ tests to determine the intelligence of the children.  Additionally, researchers measured physical attributes such as: chest circumference, height, lung capacity, and weight – these helped determine whether exposure influenced growth.  Results determined that IQ scores differed between the control group (105) and the medium arsenic group (101).

The high arsenic group exhibited more substantial IQ reduction to a score of 95.  The average IQ score for the group exposed to high fluoride was 101; this was the same as the medium arsenic group.  More troubling is the fact that high-fluoride exposure significantly decreased height compared to the control group.

Authors concluded that development (both intellectual and physical) is detrimentally influenced by high fluoride exposure.  It should be noted that fluoride exposure considered “high” was 8.3 mg per liter; this is considerably more than the amount within drinking water in the United States, containing an average of 0.7 mg per liter.  The results from this study were fairly predictable – fluoride is neurotoxic in high quantities.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/17450237

1994: A study from the early 1990s documented that although the human blood-brain barrier serves to prevent accumulation of fluoride within the brain, some fluoride can still enter the brain.  Researchers noted that surveys documented adverse neurological effects of fluoride pollution including memory and cognitive impairments.  For this reason, researchers conducted a review of literature to determine whether neurological impairment is caused by fluoride exposure, particularly in industrial settings.

Upon assessment of individual case studies, there was a relationship between fluoride exposure and neurocognitive dysfunction.  Some studies noted significant impairments in concentration and memory that may have been triggered by fluoride exposure.  Researchers speculate that fluoride may alter brain function via a complex mechanism of action.

This mechanism of fluoride’s action within the brain may involve: altering calcium currents, manipulating enzyme configuration, preventing adenylyl cyclase activity, and enhancing phosphoinositide hydrolysis.  Despite documented associations between fluoride exposure and neurocognitive deficits, it cannot be assumed that fluoride was the cause.  That said, the potential of fluoride to impair neurocognitive function warrants further investigation.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/8056997

Limitations of Research Investigating the Neurotoxicity of Fluoride

There are several limitations associated with the research investigating the neurotoxicity of fluoridated drinking water.  The biggest limitation is that none of the research involved directly measuring fluoride levels within participants.  In addition, the studies suggesting a neurotoxic effect of fluoride note that neurotoxicity is caused by high concentrations of 8.3 mg per liter.

  • Confounding factors: In all of these fluoride studies, it is important to consider potential confounds. While researchers may have done their best to adjust for confounds, these adjustments shouldn’t be considered perfect.  Despite the fact that high fluoride exposure was associated with IQ reductions, other factors such as other chemicals (toxins) within water, air pollution, socioeconomic status, parenting, teaching, etc. – could’ve played a role.
  • Fluoride concentrations: Only extremely high concentrations of fluoride were suggested to impair neurocognitive function. No significant impairments were noted among those exposed to low or even moderate levels of fluoride.  One study considered fluoride damaging at an estimated 8.3 mg per liter – over 3 times the amount in United States drinking water.
  • Measures: To determine the impact of fluoride on intelligence, researchers aimed to measure intelligence and fluoride exposure. The problem is that measuring fluoride exposure is relatively difficult.  Instead of measuring fluoride concentrations within a person’s body, they resorted to measuring fluoride within drinking water and/or determined “severity of fluorosis.”  Fluoride concentrations in water may be variable based on when samples were collected and severity of fluorosis may be influenced by fluoride sources other than drinking water.
  • Study designs: It would be helpful to conduct a placebo-controlled, randomized, double-blind study to determine whether fluoride exposure alters neurodevelopment and/or is neurotoxic. A large-scale, long-term study with various groups such as: non-fluoridated, minimal fluoridation (0 mg to 0.7 mg per liter), modest fluoridation (0.7 mg to 1.2 mg per liter), moderate fluoridation (1.2 mg to 3.4 mg per liter), and high fluoridation (3.4 mg to 10 mg per liter) – would help us understand the neurological effects of fluoride.

Debate: Are we choosing between tooth decay and intelligence?

Advocates of water fluoridation suggest that it provides significant cavity protection and reduces inequalities of dental health.  A review of evidence from 2002 documented that fluoride likely decreases cavities between 18% and 50%.  Antagonists of water fluoridation argue that fluoride is likely neurotoxic to the brain, especially among young children and infants.

A study from Italy suggested that water fluoridation is likely unnecessary in developed countries where cavities are fairly uncommon.  Based on the currently available research, it seems as though fluoridation of water between 0.7 ppm and 1.2 ppm is likely safe.  There is insufficient evidence to suggest that this amount is neurotoxic and/or deleterious to general health.

Detractors of water fluoridation argue that although the available research is of poor quality and/or lacking to support the idea that fluoride causes neurotoxicity, it doesn’t necessarily mean that there’s no risk.  Both animal and human studies suggest that high amounts of fluoride is damaging to health, especially over a long-term.  Moreover, some argue that the chemical addition of fluoride to drinking water is a violation of human rights and is a waste of tax money.

  • Source: https://www.ncbi.nlm.nih.gov/pubmed/18584000
  • Source: https://www.ncbi.nlm.nih.gov/pubmed/17333303
  • Source: http://ehp.niehs.nih.gov/pdf-files/2013/Mar/ehp.1206192R_508.pdf

Further Research of Fluoride-Induced Neurotoxicity is Warranted

Just because there are several limitations associated with research investigating the neurotoxic potential of fluoride does not mean we should assume fluoride is non-toxic.  There is considerable need to conduct studies with robust designs to test fluoride intake at various quantities to determine whether it is causing brain damage and/or killing brain cells.

  • Dosage effect: Like many chemicals, the dosage often makes the poison. Nearly anything (including water) when ingested at a high enough dose can result in detrimental neurobiological effects.  Most evidence suggests that fluoride is relatively safe in humans within the range of 0.7 mg to 1.2 mg per liter – the amount being added to our drinking water.  Future research should attempt to determine the amount of fluoride it takes to elicit neurotoxic effects in adults, teens, children, and infants and whether there is a “minimal effective dose” that provides both dental protection without altering the brain.
  • Mechanisms of neurotoxicity: The specific mechanisms by which fluoride causes neurotoxicity in the brains of humans aren’t well understood. It may be beneficial to study how fluoride could alter neurological function and whether it affects neurotransmission and neuronal signaling.  It would also be beneficial to explore whether lifelong fluoridation of 1.2 mg affects the brain more significantly than lower exposure of 0.7 mg, and whether individuals that have never ingested fluoride have different brain activation.
  • Neuroimaging: The use of neuroimaging may be useful to detect the acute effects of fluoride ingestion in the brains of humans. Perhaps a tracer could be used to assess how much fluoride makes its way into the brain of humans following ingestion of amounts within drinking water.  In addition, perhaps neuroimaging could attempt to determine the impact of fluoride on the brain over an extended period of time.

Fluoride’s Effects on Animal Brains (Research)

Although further research is warranted to determine the effect of fluoride on human brains, more research is also warranted in animals.  Most animal studies involve administration of abnormally high doses of fluoride rather than normative levels found in drinking water.  Therefore it is difficult to determine whether fluoride is solely neurotoxic at high doses or a concern at any dose.

Included below are various studies investigating the neurotoxicity of fluoride in animals such as: rats, mice, ducks, and fish.  Nearly every study determined that high concentrations of fluoride are neurotoxic and can: alter neurodevelopment, DNA, neurons, synapses, metabolism, and can even have detrimental effects on future generations.

2014: A study published in 2014 documents the fact that fluorine is considered both “toxic” and “reactive” as a chemical.  It is widespread throughout the environment and be detrimental to the health of the body when ingested and/or absorbed.  To better understand how fluorine impacts the brain and facilitates neurotoxicity, researchers administered sodium fluoride (NaF) to a group of rats.

Following administration of sodium fluoride, researchers used: neuroimaging (MRI, PET, CT), the Morris water maze test, and Western blotting techniques – to assess the rats.  The assessments revealed: reductions in intelligence, altered neuronal morphology, changes in absorption of glucose, and changes in expression of various genes.  Researchers mentioned that treatment with sodium fluoride impaired both learning and memory.

Additionally, the sodium fluoride promoted degeneration of neurons, ultimately killing brain cells.  Expression of various transporters and proteins were downregulated, while levels of BDNF increased.  It was speculated that the neurotoxicity of fluoride could be related to downregulation of glucose transportation and neuronal degeneration.

It cannot be assumed that similar changes occur in the brains of humans exposed to fluoride, but the possibility cannot be dismissed.  The type of fluoride used in the study, sodium fluoride (NaF) is commonly used in toothpaste, mouthwash, dental preparations, and even supplements.  Although sodium fluoride could be used to fluoridate water, it is though that fluorosilic acid is more commonly used – possibly eliciting slightly different effects.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/23982469

2014: A study investigated how fluoride affects a species of ducks called “merganser” and fish.  They focused their research on merganser and fish inhabiting the Odra estuary within Poland.  Researchers measured concentrations of fluoride within the bone, brain, and pineal gland of merganser ducks, and measured fluoride concentrations within the digestive tract of fish.

To determine concentrations of fluoride, researchers utilized the potentiometric method.  Measures indicated that the pineal gland was most affected by fluoride in the merganser ducks compared to the bone and brain.  Median concentrations within the pineal gland ranged from 760 mg/kg (highest) to 190 mg/kg (lowest).

Within the fish, concentrations of fluoride spanned between 37 mg/kg to 640 mg/kg.  Researchers documented a correlation between the bodyweight and length of the fish and fluoride exposure.  Authors speculate that in the Odra estuary, merganser ducks are ingesting approximately 15 mg of fluoride.

Fortunately the high concentrations of fluoride found within merganser ducks haven’t been reported in the brains of humans.  That said, it remains important to consider the possibility that human brains may accumulate more fluoride than suspected.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/24744187

2011: Research has demonstrated that sodium fluoride impairs memory performance in rodents.  A study published in 2011 investigated how addition of sodium fluoride (100 ppm) to the drinking water of rats would impact neurotransmitter levels (within the brain) and open-field habituation.  Rats were divided into the following groups: 45 days of tap water (control group), 15 days tap water followed by sodium fluoride for 30 days, and sodium fluoride for 30 days followed by 15 days of tap water.

Results indicate that sodium fluoride increases serotonin and norepinephrine levels in various regions of the brain (hippocampus, neocortex, striatum), plus increases dopamine in the striatum.  Open-field habituation was impaired as a result of the fluoride exposure.  Authors note that sodium fluoride impairs memory and significantly alters neurotransmitter concentrations in specific areas of the brain.

It should be noted that 100 ppm of fluoride is considerably more than would ever be ingested as a result of fluoridated water in humans.  Rats are smaller than humans and are being given approximately 143 times the amount of fluoride that is in United States drinking water (0.7 ppm).  That said, very small-scale changes to neurotransmitter densities may occur in humans as a result of fluoridated water.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/19957215

2011: It is known that high concentrations of fluoride (100 ppm to 200 ppm) detrimentally affect the neurophysiological function of rats.  Research has suggested that high concentrations of fluoride can alter thyroid hormones (decreasing T3 and T4), decrease acetylcholinesterase activity, and impair aspects of learning and memory.  Evidence suggests that fluoride promotes degeneration of neurons and other cells in rats.

Rats administered high concentrations of fluoride have a tougher time navigating through a maze.  The fluoride impaired rats abilities to learn and retain new information, plus the information that they were able to learn was at a considerably slower rate than the non-fluoridated rats (control).  Furthermore, when fluoride’s effect is assessed over several generations, the third generation experiences significantly more impairments than the first and second generations.

This supports the idea that ingestion of fluoride across several generations results in cumulative deleterious neurodevelopmental effects.  While the implications of extremely low-level water fluoridation aren’t well-documented among humans, perhaps there are (subtle) deleterious consequences in regards to the neurodevelopment of successive generations.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/21755305

2009: A study investigated the neurotoxicity of fluoride as a standalone toxin and when administered with aluminum – within the brains of rats.  Researchers documented alterations in specific regions of the brain as induced by fluoride and aluminum.  Fluoride exposure was noted to increase oxidative stress, increase lipid peroxidation, and decrease superoxide dismutase (an antioxidant enzyme).

Neurotransmitter concentrations of serotonin, dopamine, and norepinephrine were substantially altered.  Co-administration of fluoride and aluminum exacerbated neurotoxicity compared to the standalone fluoride.  While fluoride should be considered neurotoxic in rats, administration of another toxic chemical (e.g. aluminum) could synergistically promote increased neurotoxicity.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/19538017

2009: A study investigated the effects of fluoride on oxidative stress in the brains of 24 rats.  In addition, researchers aimed to determine whether melatonin or buffalo pineal proteins could offset some of the fluoride-induced oxidative stress.  The rats were assigned to one of four groups: fluoride (150 mg/L), fluoride + buffalo pineal proteins, fluoride + melatonin (10 mg/kg), or the control group.

Upon analysis of brain tissue to determine oxidative stress, it was noted that malondialdehyde (MDA) was significantly increased and glutathione (GSH) was significantly decreased as a result of fluoride.  Results suggested that both buffalo pineal proteins and melatonin helped offset some of the fluoride-induced oxidative stress within rat brains.  Therefore administration of buffalo pineal proteins and/or melatonin may offset fluoride-induced neurotoxicity.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/19159082

2002: Researchers investigated the facilitation of apoptosis (programmed cell death) and DNA damage as a result of sodium fluoride in rats.  The rats were divided into multiple groups, one of which received injections of distilled water with fluoride, and the other which served as a control.  A technique called “Comet Assay” was able to determine the degree of apoptosis and DNA damage.

Assessments indicated that “serious” DNA damage occurred within neurons of the rats receiving the fluoride compared to the control group.  Fluoride was suggested to significantly increase apoptosis within the hippocampus and pallium within the brains of the rats compared to the control group.  This suggests that fluoride is capable of killing brain cells and damaging DNA.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/12411198

2002: Chronic high level exposure to fluoride can lead to “fluorosis,” which has neurotoxic effects within the brains of rats.  To determine the mechanisms responsible for neurological dysfunction as a result of fluoride exposure, researchers measured nAChR (nicotinic acetylcholine receptor) densities within rat brains.  The rats had received either 30 ppm or 100 ppm of fluoride within their drinking water for 7 months.

Results indicated that significant reductions in [3H]epibatidine binding sites within the brains of rats receiving water with 100 ppm fluoride.  Among the rats receiving 30 ppm fluoride in their water, no significant changes in the number of [3H]epibatidine sites was observed.  However, both groups (30 ppm and 100 ppm) experienced a downregulation in the number of [125I]alpha-BTX binding sites.

Levels of nAChR alpha-4 subunit protein were downregulated with 100 ppm fluoride, but not with 30 ppm fluoride.  Levels of nAChR alpha-7 were downregulated significantly regardless of fluoride amount (30 ppm and 100 ppm).  The downregulation of certain nAChRs as a result of fluoride exposure may lead to cognitive deficits in areas of learning and memory.

Researchers speculate that downregulation of nAChRs is partially responsible for neurological impairments stemming from fluoride exposure.  Understand that the study utilized fluoride levels that were significantly higher than the amounts in human drinking water (0.7 ppm).  It is unclear as to whether low-grade fluoride exposure has any neurotoxic effects.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/12460657

1999: A study published in 1999 documented the effects of sodium fluoride consumption on learning-memory performance in mice.  Researchers analyzed the brains of the mice and tested their learning-memory performance within a Y-maze.  Results suggested that the learning abilities of the mice was significantly impaired as a result of the fluoride.

In addition, there was a substantial decrease in post-synaptic density, whereas the width of the synaptic cleft had increased.  High intake of fluoride is thought to alter synaptic functioning in mice, specifically by decreasing post-synaptic density and widening synaptic clefts.  It is unclear as to whether similar effects may occur in human brains.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/11938978

1998: Another study analyzed the effects of a complex called “fluoroaluminum” (which combined fluoride and aluminum) compared to standalone sodium fluoride (NaF) – on the brains of adult rats.  A total of 27 rats were given either: distilled water (control group), fluoroaluminum, or sodium fluoride – for a total of 52 weeks.  Researchers then conducted tissue analyses of the rat brains using various histological techniques.

Results failed to show differences in bodyweight between the groups after 52 weeks.  The group receiving the fluoroaluminum experienced the greatest degree of neurological change; likely due to the synergistic neurotoxic effects of fluoride and aluminum.  Despite the fluoroaluminum group enduring significantly greater neurotoxic effects than the fluoride and control groups, the fluoride group exhibited significantly greater neurotoxicity than the control group.

This suggests that should fluoride get ingested with another neurotoxin (such as aluminum), the combination of both may significantly impair brain function.  That said, it is apparent that fluoride as a standalone chemical promotes neurotoxicity.  Similar neurotoxic effects may occur in humans that ingest fluoride plus aluminum.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/9518651

1995: A study conducted in 1995 analyzed the effect of fluoride exposure on the behavior and bodyweight of rats.  Sodium fluoride was administered prenatally via injections and eventually in the form of drinking water with either: 0 ppm, 75 ppm, 100 ppm, or 125 ppm.  The fluoride administration occurred for a period of 6 to 20 weeks.

Researchers assessed behavior and determined that fluoride exposure caused behavioral deficits.  These deficits were directly related to dose, indicating that the greater the dose of fluoride ingested, the greater the severity of deficits.  Perhaps most concerning is the fact that the rat models in this study had plasma concentrations of fluoride that were akin to humans exposed to high fluoride.

This suggests that humans exposed to abnormally high quantities of fluoride may experience behavioral deficits and/or abnormalities as a result of fluoride exposure.  Further research is warranted to investigate the implications of fluoride exposure in humans.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/7760776

Dangers of Fluoride in Drinking Water (Brain Damage)

Based on the evidence from human and animal studies, to assume there’s no risk associated with addition of fluoride to drinking water is relatively short-sighted.  While no significant health risk has been found at current levels of 0.7 ppm, future research may change our perspective.  It is known that high levels of fluoride are neurotoxic, damaging the brain.  It is possible that extremely low levels such as 0.7 ppm are non-neurotoxic, but they may still elicit subtle neurotoxic effects.

  • Abnormal brain development: Fluoride in water appears to be especially harmful for infants and young children. Many experts believe that the brain continues developing throughout the mid-20s, meaning until around age 25 – the brain is especially sensitive to exogenous substances.  Ingestion of fluoride may blunt neurodevelopment of the brain and lead to suboptimal development.
  • Behavioral changes: Evidence from rodent studies suggests that fluoride is capable of altering behavior, especially among young rats. Rodents administered high doses of fluoride exhibit behavioral deficits and don’t explore as much in a novel environment.  It could be theorized that similar changes would occur in humans or maybe have occurred to a lesser extent.
  • Brain damage: Fluoride is known to facilitate apoptosis or programmed cell death within certain regions of the brain. Those consuming high concentrations of fluoride are literally killing their brain cells without knowing it.  While significant numbers of brain cells may not die with low-grade exposure (e.g. 0.7 ppm), it is possible that a clinically insignificant degree of apoptosis occurs.
  • Dental fluorosis: A condition known as dental fluorosis can develop among those exposed to high concentrations of fluoride. While fluoride is known to protect teeth from decay, too much fluoride can facilitate the appearance of white splotchy patterns on the teeth.  These changes in appearance of tooth enamel could be avoided by reducing fluoride.
  • DNA damage: Researchers have determined that high levels of fluoride can damage DNA and genetic expression within mice. While the damage was noted to occur most prominently following significant exposure, certain less detectable (unwanted) changes may occur as a result of fluoridated water ingestion.
  • Generational effects: Highly concerning is the fact that fluoridated water’s effect on DNA, genetic expression, and neurological health may become increasingly harmful with successive generations. Research has documented detrimental effects of fluoride ingestion across three generations of rats and discovered that the impairments were significantly greater in the third generation compared to the first two.  It is possible that many subtle fluoride-induced DNA abnormalities are worsening in humans exposed to high fluoride across generations.
  • Hormone levels: Fluoride is capable of altering levels of thyroid hormones T3 and T4, both of which are involved in a variety of neurophysiological processes. While significant alterations were found in animal studies following administration of high concentrations of fluoride, subtler effects may be evident among humans.
  • Lower IQ: Despite the significant limitations associated with research of fluoride in humans, some research suggests that fluoride from drinking water may lower IQ. While expert interpretation of the results indicates that up to 7 IQ points may be lost as a result of fluoride, cumulative lifelong fluoride exposure may result in greater IQ reductions.  Perhaps the collective IQ of the nation has been lowered as a result of fluoridated water.  Some speculate that fluoridation of water has halved the number of geniuses and doubled the amount of individuals with handicaps as a result of IQ reduction.  For every IQ point lost, some estimate that it the economy loses up to $1,000 per year. (Read: How to Increase Your IQ).
  • Learning and memory deficits: Testing in humans exposed to high concentrations of fluoride exhibit learning and memory impairments. These findings are consistent based on research involving fluoride administration to animal models.  It seems as though learning and memory deficits are most pronounced with greater fluoride exposure.
  • Neurotransmitter levels: It is possible to consider the fact that fluoridation of water could contribute to certain mental illnesses by disrupting baseline levels of monoamines. Neurotransmitters such as acetylcholine, serotonin, dopamine, and norepinephrine are altered following exposure to fluoride.  Increases in serotonin, norepinephrine, dopamine, and acetylcholine have been observed in rodent brains as a result of fluoride exposure.
  • Receptor densities: Fluoride appears to downregulate various receptors involved in neurotransmission. Studies investigating fluoride’s impact on nAChR discovered a significant downregulation of these receptors, likely contributing to learning and memory impairments.  It is extremely likely that more receptors besides nAChR are detrimentally altered via fluoridation.
  • Synapse alterations: Some rodent studies indicate that high fluoridation can decrease post-synaptic density, while simultaneously widening synaptic clefts. These synaptic changes could trigger a cascade of other neurological changes.  Furthermore, lifelong fluoride exposure may shift synaptic functioning to a more significant extent than was evidenced in these studies.

Benefits of Fluoride in Drinking Water (Dental Health)

Proponents of water fluoridation consider benefits significant.  These benefits of fluoridation include: cavity reduction, prevention of tooth decay, possible reversal of decay, and minimizing dental inequality between those of low and high socioeconomic status.  It is unclear as to whether the benefits are as significant as suggested.

  • Cavity reduction: Fluoridation of water is considered an effective way to prevent cavities in people of all ages (children and adults). Some studies have suggested that fluoridation of water reduced cavity rates by up to 50% in children and 27% in adults.  Whether the cavity reduction rates as a result of fluoridation are as high as claimed is up for debate.
  • Dental care replacement: For individuals who fail to see a dentist regularly (every 6 months), fluoridation of drinking water may be preserving dental health. In the United States, regular dental checkups are not mandatory and as a result many people don’t go to the dentist.  Drinking water with 0.7 ppm fluoride may be preventing tooth decay and cavity formation.
  • Equality of oral health: Many speculate that fluoridation of water minimizes inequalities in dental health between individuals from wealthy and poor families. That said, the quality of these studies is questionable.  Some believe that significant inequalities in dental care are prevalent regardless of water fluoridation.  Proponents of fluoridation are quick to highlight the fact that its addition could minimize oral health inequalities.

Why the Risks of Water Fluoridation Outweigh the Benefits

Although extremely low concentrations of fluoride are added to drinking water (0.7 ppm), there’s some evidence to believe that ingestion of any amount may lead to neurotoxicity.  Lifelong ingestion of low concentration fluoridation may have significantly more deleterious effects than the science is currently able to comprehend.  Looking back in 20 years, we may view the fluoridation of water as being a major mistake rather than being considered among the greatest health achievements of the 20th century.

Addition of fluoride to water provides no nutritional value, and the fluoride added to drinking water is considered byproduct of industrial waste.  Sure it can help prevent cavities, reduce likelihood of tooth decay, and modulate inequalities between wealthy and poor in regards to dental health.  That said, it is added to drinking water without any consent from citizens of the United States – it is to be unconditionally accepted because “government knows best.”

In European countries that do not add fluoride to water (e.g. Germany), cavity rates have managed to decline, even without fluoridation.  It is possible that cavity rates will continue to decline as education, society, and ultimately civilization continues to advance.  We have a better understanding than ever before regarding what it takes to prevent cavities and tooth decay; water fluoridation seems unnecessary.

An estimated 95% of the fluoride that’s added to your water is considered “hydrofluorosilic acid” (H2SiF6), a toxic liquid byproduct attained by scrubbing phosphate fertilizer off of chimney stack manufacturers.  It is a common toxic waste substance derived from aluminum, fertilizer, and nuclear industries – this is not the natural element of fluoride, rather it’s nothing more than toxic waste.

Sounds pretty appealing, eh? To make matters worse, there’s motivation for companies to get rid of this hydrofluorosilic acid by pawning it off into your drinking water.  It’s relatively costly to get rid of due to the fact that it’s hazardous and toxic.  Dumping it into rivers or lakes would have severe downstream environmental ramifications, also contributing to air pollution.

Using some sort of broken logic, the government is willing to add a low amount of a potentially neurotoxic substance to our drinking water, justifying its addition with the fact that it’s just a small amount.  While any substance in excess is often neurotoxic, certain substances could be risky in low amounts.  Adding low amounts of a known toxin (hydrofluorosilic acid) to drinking water of the masses is nothing more than an unjustified health gamble.

Humans were not evolutionarily adapted to consume the industrial toxin that is hydrofluorosilic acid, and full implications of its addition to drinking water are poorly understood.  Even if the consequences of its addition aren’t severe, it is important to consider that it may be especially detrimental to the health of vulnerable populations, even in extremely low amounts.  In the future, it is likely that water fluoridation will become obsolete; in some areas of the country like Portland, Oregon – it already has been ousted.

While based on the current science it’s tough to suggest that 0.7 ppm fluoride is definitively dangerous, adding any exogenous toxin to drinking water (regardless of the amount) should be considered risky.  The question to ask yourself is: “If I could choose to have fluoride in my drinking water – or drinking water without fluoride, what would I choose?”  A majority of educated citizens would likely opt out of water fluoridation in favor of cleaner, purer drinking water – minimizing their risk of neurotoxicity.

Ironically, most of those in opposition to removal of fluoride from water have reputations to protect as dentists and/or are stubborn skeptics, willing to wait (potentially decades) until robust scientific research recommends against fluoridation.  It should be mentioned that certain dentists oppose the idea of water fluoridation, suggesting that it’s likely hazardous to human health.

What to do if you’re concerned about fluoride-induced neurotoxicity?

If you’re highly concerned about the potential adverse health effects of fluoride, there are some steps you can take.  Firstly, you could invest in a water filtration system that removes all fluoride from your tap water.  Other things you can do include: voting to remove fluoride from drinking water, supporting more scientific research, seek out alternative water sources, and/or take certain supplements.

  1. Water filtration systems

There are many water filtration systems that remove all fluoride from your drinking water.  Some of these systems can cost upwards of several hundred dollars, so be prepared to do your research to find one that suits you and/or your family.  Many filtration systems filter out other potentially hazardous contaminants as well.

Another option you have is to purchase water from a supplier that ensures zero fluoridation.  Certain companies may sell water without fluoride in grocery stores and/or online.  While it sounds somewhat extreme to purchase non-fluoridated water, if you are really concerned – this is a step you may want to consider if you don’t have a water filtration system.

  1. Vote to abolish fluoridation of water

It’s relatively ridiculous that the government can add a chemical like fluoride without public consent.  In this case, the government is deciding what’s best for your teeth is to add fluoride to water.  Although they’ve finally (as of 2015) lowered the amount of fluoride in drinking water to an average of 0.7 ppm in all areas of the country, you still have no right to choose whether you’re drinking fluoridated water.

Assuming your city has some sort of petition in place to stop fluoridation of water, you may want to support it.  The first city to remove fluoride completely from their water is Portland, Oregon.

  1. Encourage more scientific research

It’s important to acknowledge that fluoride at 0.7 ppm may be completely safe for you, your brain, and have no detrimental impact on your health.  However, it is also important to consider that the consequences of just 0.7 ppm fluoride within drinking water may be significantly worse than the current science indicates.  Encourage and support further (quality) research investigating the effects of fluoridated water intake among humans.

More quality research will unveil the truth in regards to how bad (or not bad) fluoride really is.  If a group of hardcore scientists really wanted to study fluoride, we’d probably have more evidence to know the true consequences of water fluoridation.

  1. Supplements for neuroprotection

It’s possible that taking the right supplements along with proper nutrition could completely offset and/or mitigate fluoride induced neurotoxicity.  There is strong evidence from rodent studies to support the idea that supplementation of: curcumin (derived from the spice turmeric), selenium, and melatonin may act as neuroprotective agents against fluoride-induced neurotoxicity.  Below are studies supporting the supplementation of curcumin and selenium – the study supporting melatonin (published in 2009) was discussed above.

Curcumin (2014)

A study published in 2014 suggests that curcumin (Cur) may be able to offset fluoride-induced neurotoxicity.  Curcumin is the primary active ingredient within the spice turmeric and is known to have potent antioxidant effects.  In fact, it has been investigated as a potential adjunct treatment for clearance of plaques in Alzheimer’s disease.

This study involved testing whether administration of curcumin could prevent fluoride neurotoxicity in mice.  Administering fluoride to mice results in increased lipid peroxidation and promotes neurodegeneration within various regions of the brain.  However, when curcumin is co-administered with fluoride, it decreases biomarkers of neurotoxicity including lipid peroxidation and neurodegeneration.

While this study was conducted in mice, preliminary benefits suggest that curcumin is likely to elicit neuroprotective effects in the brains of humans.  In theory, large quantities of dietary turmeric and/or curcumin supplements may help mitigate fluoride-induced neurotoxicity.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/24696547

Selenium (2009)

A study from 2009 investigated the neuroprotective effects of selenium on fluoride-induced oxidative stress within the brains of mice.  The study involved dividing mice into several groups including: a sodium fluoride group (20 mg/kg), selenium + sodium fluoride group, and a control group.  The study spanned over the course of 14 days and noted that sodium fluoride decreased bodyweight and caused brain damage in mice.

However, both bodyweight and brain damage were offset as a result of co-administration of selenium.  Nearly all fluoride-induced oxidative and metabolic changes were reversed with administration of selenium.  This suggests that supplementation with selenium may reverse fluoride-induced neurological abnormalities.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/20143719

Conclusion: Fluoride possibly safe, neurotoxicity also a possibility

From a present-day scientifically objective perspective, there is insufficient evidence to support the notion that fluoridation of drinking water is neurotoxic and detrimental to general health.  Fluoridation of water is seemingly safe at current levels of 0.7 ppm (0.7 mg/L).  Nonetheless, it is important to consider the possibility that even at a level of 0.7 ppm, fluoride could be neurotoxic (even if the neurotoxicity is so low-grade as to be undetected by currently available scientific analyses).

It is also important to consider that sodium fluoride (NaF) is not the type of fluoride that’s being added to your drinking water; sodium fluoride is the kind added to toothpaste.  Fluorosilic acid is the type of fluoride being added to your drinking water.  That said, none of these industrially-extracted fluoride sources should be considered healthy for human [or animal] ingestion.

Application of fluoride to teeth is what prevents cavities, not drinking it.  To me (and many others) the risk of potential neurotoxicity (and other adverse health effects) significantly outweighs the cavity prevention potential as a result of water fluoridation.  The bottom line is that all humans should have the right to receive pure, unadulterated, non-fluoridated drinking water – regardless of what anyone – including the omniscient and omnipotent government – thinks.

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