Whether you have strong views for or against water fluoride, this is what you need to know.
Fluorides are compounds that combine the element fluorine with another substance, usually a metal. Examples include sodium fluoride, stannous fluoride, and fluoride monofluorophosphate.
Fluorides are absorbed into the blood through the digestive tract, and they are stored in areas high in calcium, such as the bones and teeth.
In 2015 United States Public Health Service (PHS) recommended that public water supplies contain 0.7mg fluoride per liter (mg/L) of drinking water to help prevent tooth decay.
Natural drinking water sources in the US have an average fluoride level of about 0.2 mg/L.
The US Environmental Protection Agency (EPA) has set a safe maximum amount of fluoride allowable in drinking water of 4.0 mg/L. Long-term exposure to levels higher than this can cause a condition called skeletal fluorosis, in which fluoride builds up in the bones. This can eventually result in joint stiffness and pain and can also lead to weak bones or fractures in older adults.
The EPA has also set a secondary standard as a guideline of no more than 2.0 mg/L to help protect children (under the age of 9) from dental fluorosis. In this condition, fluoride collects in developing teeth, preventing tooth enamel from forming normally. This can cause permanent staining or pitting of teeth.
For bottled water with no fluoride added, the maximum fluoride level allowed is 2.4 mg/L in cold weather.
Most of the concern about cancer seems to be around osteosarcoma. One theory on how fluoridation might affect the risk of osteosarcoma is based on the fact that fluoride tends to collect in parts of bones where they are growing. These areas, known as growth plates, are where osteosarcomas typically develop.
The theory is that fluoride might somehow cause the cells in the growth plate to grow faster, which might make them more likely to eventually become cancerous. Osteosarcoma is rare cancer. Only about 400 cases are diagnosed in children and teens yearly in the United States.
Fluoride can become concentrated in bone-stimulating bone cell growth, altering the tissue’s structure, and weakening the skeleton.
Preliminary research in laboratory animals suggests that high levels of fluoride may be toxic to the brain and nerve cells. And human epidemiological studies have identified possible links to learning, memory, and cognition deficits, though most of these studies have focused on populations with fluoride exposures higher than those typically provided by U.S. water supplies.
Systemic fluoride uptake is suspected of causing adverse effects, in particular, neurotoxicity during early development. The latter is supported by experimental neurotoxicity findings and toxicokinetic evidence of fluoride passing into the brain.
Studies suggested that a higher fluoride content of residential drinking water was associated with poorer IQ performance at school age.
Approximately 75–90% of ingested fluoride is absorbed and readily distributed throughout the body, with 99% of retained fluoride being bound in calcium-rich tissues such as bone and teeth as well as the calcified parts of the pineal gland.
Fluoride also crosses the placenta and reaches the fetus and the amnionic fluid. The fluoride concentration in breast milk is low, less than 0.01 mg/L, and formula can therefore contribute much higher intakes, especially when prepared with high-fluoride water. Children and infants retain higher proportions of absorbed fluoride compared to adults, i.e., about 80–90%, as compared to about 50–60% in adults.
In conclusion, depending on demographics, water fluoridation can be higher or lower, but since EPA controls the fluoride content allowed to be in drinking water, over ingestion of fluoride and toxicity incidents should be low.
Dental products containing fluoride are considered safe since they are not swallowed.
Fluoride varnishes, toothpaste or rinses only work as a topical application into the tooth structure to remineralize weakened enamel areas which later on could become caries.
Multiple long-term studies have shown 24% of caries lesions are prevented by using fluoride toothpaste compared to non-fluoride toothpaste.
To read more about it, please refer to the following references.
References:
- https://www.cancer.org/cancer/cancer-causes/water-fluoridation-and-cancer-risk.html
- https://www.ada.org/en/member-center/oral-health-topics/fluoride-topical-and-systemic-supplements
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6923889/
- Is Fluoridated Drinking Water Safe? | Harvard Public Health Magazine | Harvard T.H. Chan School of Public Health
Jennifer Pettit, CRDH.
HQ DONTICS Team.
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