Below is a list of scientific studies and articles related to fluoride and water fluoridation.
PAROTID GLANDS: Animal study finds fluoride exposure results in oxidative stress and changes in oxidative biochemistry of the largest salivary gland which stimulates compensatory mechanisms and increases risk to the complex cell cytoskeleton.
- Miranda GHN, et al. Effects of long-term fluoride exposure are associated with oxidative biochemistry impairment and global proteomic modulation, but not genotoxicity, in parotid glands of mice. PLoS One. 2022 Jan 27;17(1):e0261252.
LOWER PERFORMANCE IQ: Examined children's IQ at three separate time points (age 4, 5, and 6–12 years) to determine longitudinal and domain specific effects of prenatal fluoride exposure on IQ in mother-child dyads from the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) cohort. Found prenatal exposure to fluoride, which is primarily from fluoridated salt programs, is associated with sustained impacts on IQ. Non-verbal abilities may be more susceptible to impairment from prenatal fluoride exposure as compared to verbal abilities.
- Goodman C, et al. Domain-specific effects of prenatal fluoride exposure on child IQ at 4, 5, and 6–12 years in the ELEMENT cohort. Environmental Research. 2022
IODINE & IQ: MIREC study of child-mother dyads finds “the association between prenatal fluoride exposure and full-scale intelligence previously identified in this cohort was exacerbated by low maternal iodine in pregnancy among boys. These results, which were found among mother-child pairs living in fluoridated and non-fluoridated communities in Canada, underscore the importance of sufficient iodine intake in pregnancy to minimize the neurotoxicity of fluoride in boys.” https://www.mdpi.com/2072-6643/14/14/2920/htm
- Goodman CV, et al. Iodine Status Modifies the Association between Fluoride Exposure in Pregnancy and Preschool Boys’ Intelligence. Nutrients 2022, 14, 2920.
GENOTOXIC: According to public health authorities, fluoride has a narrow range between the concentration which is beneficial and that which has adverse effects. The primary exposure to the fluoride-ion is through drinking water supplemented with fluorosilicic acid (FA). FA in ‘safe’ doses causes DNA damage in human osteoblast cells, reduces the telomere length and induces oxidative stress. Although combinations of fluoride with other toxins could have a synergistic effect, this study found that FA alone affects the genomic integrity of human bone cells.
MALE FERTILITY: Fluoride, alone or in combination with arsenite both of which are common elements in drinking water, significantly suppressed the expression of steroidogenic enzymes and of the genes encoding these enzymes. “In conclusion, this study showed that exposure to As and F at environmentally relevant concentrations dispersed by water decreased testosterone production in Leydig cells, an important cell of the male reproductive system. The deleterious effects of even the lowest concentrations of As and F elements that can reach humans from the environment on the Leydig cell, and therefore on male infertility, emphasize necessity new safe limits for these elements.” https://pubmed.ncbi.nlm.nih.gov/36182826/
BODY & BRAIN: “Fluoride in higher concentrations or continuous exposure to lower doses are both found to induce mental imbalance in animals apart from the genotoxic, immunotoxic, and cytotoxic effects commonly observed. The behavioral profile of fluoride-treated animals has corroborated the clinical symptoms seen in fluoride-poisoned humans.”
PROBIOTICS: Adding probiotics to school milk is more effective and less costly than fluoride varnish in preventing cavities in children.
OVARIAN & TESTICULAR: Animal study from in utero through puberty showing adverse impact on reproductive function. “Approximately 80–90% of fluoride absorbed by infants and children accumulates in the body. It can enter into the umbilical cord blood of the child from the mother through the placenta. In addition, significantly high fluoride content in breast milk is indicative of fluoride exposure to infants. Young children show less resistance to the toxic effects of fluoride than adults because of under-developed defense mechanisms and highly permeable blood-brain barrier.” https://link.springer.com/article/10.1007/s12011-022-03220-8
BIRTH ANTHROPOMETRY: Using ELEMENT cohort, authors determined maternal exposure to fluoride affects length and weight of newborns with different susceptibility windows. Advises women avoid fluoride during pregnancy.
KIDNEYS: Using U.S. NHANES data, finds water fluoridation results in significantly higher plasma fluoride levels in healthy teens with lower renal function, suggesting a vicious feedback loop for those with CKD.
SKELETAL FLUOROSIS: Summary of the adverse effects of < 0.7 mg/L exposure on skeletal and non-skeletal systems finds “low fluoride can indeed cause damage to human health. As a consequence, it is necessary to formulate the more appropriate water fluoride standard by taking into account the effects of low fluoride on various bodily systems. In addition, more and more evidence suggest that there exist individual differences in the effect of low fluoride on the body… most likely due to genetic polymorphisms. Therefore, it is necessary to consider both environmental exposure and the actual genetic situation of the individuals with respect to fluoride exposure.”
BRAIN CONNECTION: Dental fluorosis (DF) is a structural tooth defect associated with a structural brain defects, i.e. “abnormal brain structure and brain function” which impacts concentration, learning, and memory, as well as increasing mental symptoms such as anxiety, tension, and depression. https://pubmed.ncbi.nlm.nih.gov/36049331/
FLUORIDE-INDUCED LIVER INJURY: Animal study validates fluoride disrupted the glycolipid metabolism in the liver and resulted in the differential expression of 35 miRNAs and 480 mRNAs. https://pubmed.ncbi.nlm.nih.gov/36222057/
NOT BENEFICIAL: Dental fluorosis (DF) is a qualitative defect in enamel from fluoride exposure early in life. DF is associated with other systemic conditions i.e. cognitive deficits, bone problems, thyroid disorders, etc. Significant incidences of DF are found in areas with 0.25 ppm fluoride in water concentration. Remineralization without fluoride exposure is advisable.
FEMALE INTESTINES: Animal study details the process whereby fluoride exposure damages intestinal cells in the absence of estrogen which is consistent with a pattern of increased gastrointestinal illness among post-menopausal women in fluoridated communities.
DOSE IN FOOD: Finds that fluoride exposure from foods prepared with fluoridated water have heavy fluoride concentrations not previously suspected that may exceed exposure from drinking water, dependent on dietary habits. Proposes reduction in fluoride exposure especially critical for low weight populations, such as infants, children and the frail.
- Sawangjang B, Takizawa S. Re-evaluating fluoride intake from food and drinking water: Effect of boiling and fluoride adsorption on food. J Hazard Mater. 2022 Oct 12,
BENCHMARK DOSE ANALYSIS: Using fluoride studies from MIREC and ELEMENT projects as input, the results of which are consistent with other studies, authors identify 0.2 mg/L as having an adverse impact on neurodevelopment. “The prospective studies offer strong evidence of prenatal neurotoxicity, and the benchmark results should inspire a revision of water-fluoride recommendations aimed at protecting pregnant women and young children.”
LIFETIME EXPOSURE: Fluoridation is the primary source of fluoride exposure for 1,629 Canadians between 3 and 79 that finds substantially higher lifetime fluoride exposure in fluoridated communities using CHMS data, increasing with age. Vulnerable subpopulations to adverse effects of fluoride noted as the young, those who are iodine deficient, and postmenopausal women. https://www.mdpi.com/1660-4601/18/12/6203/htm
KIDNEYS: This study of 1,070 adults found every 1 mg/L increment in the urinary fluoride concentrations was associated with significant increases of 22.8% in the risk of kidney function injury after adjusting for potential confounding factors. Authors conclude that long-term fluoride exposure is associated with compromised kidney function in adults, and that urinary NAG is a sensitive and robust marker of kidney dysfunction caused by fluoride exposure.
BEHAVIORAL CHANGES: Children in Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) assessed at age 12. Boys in particular did not experience significant anxiety or depression, yet had somatic behaviors based on their childhood urinary fluoride (CUF) concentrations, “seven times more likely to exhibit ‘at-risk’ internalizing symptomology.”
CRITICAL WINDOWS: Using urine samples and test scores from 596 mother-child Canadian pairs in the MIREC prospective cohort, researchers found evidence that developmental neurological damage was based on timing of fluoride exposure and gender, “Associations between fluoride exposure and PIQ (performance IQ) differed based on timing of exposure. The prenatal window may be critical for boys, whereas infancy may be a critical window for girls.”
GENES: Several genes make individuals more vulnerable to the neurotoxic impact with gender differences, also affecting mitochondria and suggesting vulnerability to dementia. Chinese study of 952 school children between 7 and 13 using water, urinary, hair and nail fluoride identified multiple neurodevelopmental metabolic pathways that result in adverse effects from low fluoride exposures. https://www.sciencedirect.com/science/article/pii/S0160412021003068
GENETIC VULNERABILITY: Dopamine relative genes affect the susceptibility of individuals to fluoride toxicity even in safe water concentrations which result in lowered IQ so that “lowmoderate fluoride exposure is inversely related to children’s IQ.”
BRITTLE BONES: “In this cohort of postmenopausal women, the risk of fractures was increased in association with two separate indicators of fluoride exposure. Our findings are consistent with RCTs and suggest that high consumption of drinking water with a fluoride concentration of ∼1 mg/L may increase both BMD (bone mineral density) and skeletal fragility in older women.” https://pubmed.ncbi.nlm.nih.gov/33822648/
OSTEOARTHRITIS: Identifies fluoride as an environmental chemical that has adverse effects on articular cartilage and osteoarthritis (OA) risk. “In full sample analysis, a 1 mg/L increase in UF (urinary fluoride) level was associated with a 27% higher risk of OA.”
PRESCHOOLERS: Polish study finds ‘optimal’ fluoride concentrations in water provide no dental benefit. Dental caries experience depended on oral hygiene and diet.
ALTERNATIVE: This systematic review and meta-analysis concludes that biomimetic hydroxyapatite-containing, fluoride-free oral care products are effective in reducing dental decay, especially in children without the risk of dental fluorosis and neurotoxicity inherent in topical use of fluoridated products. https://files.cdha.ca/profession/journal/2752.pdf
AMERICAN KIDNEYS: Using U.S. NHANES data from two recent cycles, finds ‘optimal’ amounts of fluoridated water results in high incidence of uric acid in adolescents suggesting higher risk of kidney disease and other illnesses. Identifies dose-response trend in plasma fluoride of teens.
TODDLERS: The Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) cohort included 948 mother-child pairs from Mexico City. Blinded testing of children between one and 24 months to examine associations between maternal fluoride intake from food and beverages during pregnancy and offspring neurodevelopment in this prospective and longitudinal study found, “higher exposure to fluoride from food and beverage consumption in pregnancy was associated with reduced cognitive outcome, but not with language and motor outcome in male offspring over the first two years of life.”
SAFE DOSE: Study of Mexican children and their mothers using measurements of urinary fluoride and water concentrations associated dental fluorosis and lowered IQ with fluoride dose consistent with findings of larger studies in other countries. Authors declare WHO fluoride guidelines are unsafe and hypothesize that 0.045 F-mg/day is a protective exposure
BABY BRAIN POISON: Exposure to fluoridated water (10 mg/L & 50 mg/L) beginning on the first day of pregnancy and continuing through the last day of breastfeeding shows chemical imbalances, cellular damage and changes in the hippocampus of Wistar rat offspring that would affect neurological development.
TEETH - BRAIN: Chinese study confirm 1.6 ppm v. 0.1 ppm results in children with both damaged teeth and lower IQ. Authors validate that fluoride affects thyroid function, neurotransmitters and mitochondrial energy enzymes. There were no students with low IQ found in the area with low F level. There was high IQ among the 96.6% of the students who did not experience fluorosis.
GUTS & BRAINS: Memory function was reduced and gut microbiota structure was significantly altered in fluoride-exposed mice.
INFLAMED GUTS: Exposure to fluoridated water at both doses (10 mg/L & 50 mg/L) inflame guts in rats and alters the gut microbiome as compared to control (0 mg/L).
PUBERTY: Black girls consuming optimally fluoridated water have earlier menarche.
HARMFUL ADEQUATE INTAKE (AI): Study found "the levels of dietary F- intake were below the current AI, were greater towards the end of gestation and in women who were moderately and highly compliant with Mexican dietary recommendation” in ELEMENT cohort and recommended changing future dietary recommendations due to evidence of developmental neurotoxicity at even low dose exposure. https://pubmed.ncbi.nlm.nih.gov/33602354/
CALCIUM & FLUORIDE IN PREGNANCY: Calcium intake during pregnancy lowers urinary fluoride (UF) concentrations by some unknown mechanism in ELEMENT cohort.
SAFETY: Evidence of dental fluorosis and other adverse effects to bodies and brains from supposed safe concentrations is alarming. “The safety of public health approach of drinking water fluoridation for global dental caries reduction are urgently needed further research.”
SKELETAL FLUOROSIS: This Chinese study of the pathogenetic progression of skeletal fluorosis, details how local signaling pathways, hormones, promoter DNA hypermethylation, RNA expression etc. are affected by fluoride exposure leading to pain and disability.
DEPRESSION: Animal study finds negative changes in brain structure and behavior with exposure to sodium fluoride (NAF).
HISTORICAL ANALYSIS: This historical analysis documents how the ADA suppressed the established science that vitamin D was necessary for healthy teeth and bones in order to promote falsely fluoride which was and is more profitable for their membership. “Public health may well depend on looking at professional societies no different than the way we look at the pharmaceutical industry—conflicted organizations with a power to shape conventional wisdom based on fragile evidence.”