Fluoride is a trace mineral that naturally occurs in the earth’s crust and water. It is also produced synthetically for use in drinking water, toothpaste, mouthwashes and various chemical products. In some countries like the US, Australia and UK, water authorities add fluoride to the municipal water supply. This is a public health measure to prevent dental decay and build healthy teeth in childhood. In fact, some studies have shown that adding it in areas where fluoride levels in the water are low can reduce the prevalence of tooth decay in the local population. However, concerns have arisen regarding the effect of fluoride on health; including problems with bones, teeth, and neurological development. Also, excessive fluoride exposure has been linked to several health issues.
A systematic review of studies published in The Lancet classifies fluoride as a developmental neurotoxin along with lead, mercury, arsenic and toluene. "In 2006, we did a systematic review and identified five industrial chemicals as developmental neurotoxicants: lead, methylmercury, polychlorinated biphenyls, arsenic, and toluene. Since 2006, epidemiological studies have documented six additional developmental neurotoxicants - manganese, fluoride, chlorpyrifos, dichlorodiphenyltrichloroethane, tetrachloro_ ethylene, and the polybrominated diphenyl ethers." (Philippe Grandjean, Philip J Landrigan, Neurobehavioural effects of developmental toxicity, The Lancet 2014).
A neurotoxin is a poisonous or destructive substance to the tissues in the brain, spinal cord, and nervous system. Developmental neurotoxins are linked to increases in attention deficit hyperactivity disorder (ADHD), dyslexia, loss of IQ points, disruptive behaviour and other cognitive impairments.
Harvard School of Public Health and China Medical University in Shenyang performed a joint analysis of 27 studies on the effects of fluoride. Researchers found a strong correlation between fluoride and adverse impact on cognitive development. Children in high-fluoride areas had significantly lower IQ scores than those living in low-fluoride areas. "Thus, children in highfluoride areas had significantly lower IQ scores than those who lived in low fluoride areas. Subgroup and sensitivity analyses also indicated inverse associations, although the substantial heterogeneity did not appear to decrease. Conclusions: The results support the possibility of an adverse effect of high fluoride exposure on children’s neurodevelopment." (Anna L. Choi, Guifan Sun, Ying Zhang, and Philippe Grandjean; Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis).
The World Health Organization (WHO) notes that long-term exposure to drinking water that contains more than 1.5 ppm fluoride can lead to health problems. For this reason, the WHO’s guideline limit is 1.5 ppm, considering it the safe fluoride level. Ingestion of excess fluoride, most commonly in drinking water, can cause fluorosis, which interferes with the development of tooth enamel and can cause white spots or streaks on the teeth. Even if moderate amounts lead to dental effects, chronic high-level exposure to fluoride can lead to skeletal fluorosis. In skeletal fluorosis, fluoride accumulates in the bone progressively over many years. The early symptoms of skeletal fluorosis include stiffness and pain in the joints. In severe cases, the bone structure may change, and ligaments may calcify, resulting in muscles and pain. Acute high-level exposure to fluoride causes immediate effects of abdominal pain, excessive saliva, nausea and vomiting. Seizures and muscle spasms may also occur.
Also, if ingested, fluoride can be poisonous, especially in large quantities. This is why fluoride toothpaste containers carry the warning to contact poison control if ingested.
For all these reasons, adding fluoride to drinking water is a controversial practice. If you are concerned about your fluoride intake, the best thing to do is to ask your local council about the fluoride level in your area’s water. Then, you can decide wherever not to opt for fluoride-free dental products, especially if you have young children.