When I was in elementary school once a week the school nurse would bring around a tray full of little paper cups filled with pink liquid. She instructed us to take the liquid, swish, and then spit it out. This was a common procedure in schools, like mine, where all of the students had well water. What was it? Fluoride. Even if you have/had city water you might remember the yucky fluoride treatments at the dentist. As a parent, what do I need to know about fluoride?
What is Fluoride?
Flouride is a naturally occurring anion of the element flourine (an anion is an atom missing an electron or two). It is found at some level in all drinking water and food in small amounts (prior to human intervention which adds more flouride, see below) according to the WHO Environmental health criteria.
Fluoride is a known toxin to animals and humans leading to both acute and chronic illness. It is in fact between arsnic and lead in level of toxicity. Fluoride is bioaccumulative, meaning it is kept in your tissues and not flushed out. Fluoride crosses the blood-brain barrier. Fluoride is not an essential nutrient (NRC 1993 and IOM 1997). No disease has ever been linked to a fluoride deficiency. Humans can have perfectly good teeth without fluoride.
Does Fluoride Prevent Cavaties?
Yes, since the early 20th century science has shown that fluoride is a factor in the prevention of cavities (dental caries). However, where it was assumed in the 1940s that fluoride was most effective when ingested (called systemic) it is know known that fluoride prevents cavities only on erupted teeth through topical application, such as fluoride toothpaste.
“Fluoride is most effective when used topically, after the teeth have erupted.” Cheng KK, et al. (2007). Adding fluoride to water supplies. British Medical Journal 335(7622):699-702.
“The results of more recent epidemiological and laboratory studies can be summarized by stating that posteruptive (topical) application of fluoride plays the dominant role in caries prevention.” Hellwig E, Lennon AM. (2004). Systemic versus topical fluoride. Caries Research 38: 258-62.
“Current evidence strongly suggests that fluorides work primarily by topical means through direct action on the teeth and dental plaque. Thus ingestion of fluoride is not essential for caries prevention.” Warren JJ, Levy SM. (2003). Current and future role of fluoride in nutrition. Dental Clinics of North America 47: 225-43.
“Until recently the major caries-inhibitory effect of fluoride was thought to be due to its incorporation in tooth mineral during the development of the tooth prior to eruption…There is now overwhelming evidence that the primary caries-preventive mechanisms of action of fluoride are post-eruptive through ‘topical' effects for both children and adults.” Featherstone JDB. (1999) Prevention and Reversal of Dental Caries: Role of Low Level Fluoride. Community Dentistry & Oral Epidemiology 27: 31-40.
“[E]vidence has continued to accumulate to support the hypothesis that the anti-caries mechanism of fluoride is mainly a topical one.” Carlos JP. (1983) Comments on Fluoride. Journal of Pedodontics Winter. 135-136.
This is just a brief list of the research that supports topical fluoride and denies a benefit from ingested fluoride (for an exhaustive list of research on fluoride please see here). I provided the last one just to show that this isn't something that was realized yesterday but as early as the early 1980s.
The Center for Disease Control calls the addition of fluoride to drinking water one of the 10 Great Public Health Achievements of the 20th Century. I may have mentioned that the CDC has been wrong before. So who is right? It is true that cavities in the US decreased dramatically in the last 1/2 of the 20th century, as it did all over the world. The chart to the right shows the decrease in cavities and the corresponding percentage of people with access to fluoridated drinking water. The sharp decrease doesn't match the slow increase in fluoridation.
Furthermore, the same steep decline in cavities was seen in countries that do not fluoridate their water at all (Diesendorf M. (1986). The mystery of declining tooth decay. Nature 322: 125-129.). Other factors that contribute to decreased tooth decay is topical fluoride treatment (fluoride toothpastes), better oral hygeine, and better nutrition.
Why Is There Fluoride In the Water?
This is the million dollar question. If ingested fluoride does not help prevent cavities then why are we putting it in the water? And just so we are clear it is added to drinking water. It is the only substance added to community drinking water for medical purposes – everything else is added to treat the water. This may pose a problem to some since it is compulsory medication being administered to the entire populace without informed consent. This is one reason that many European countries do not fluoridate their water supply (e.g. Germany).
But, is it just benign (?) placebo they put in the water? Actually, instead of naturally occurring fluoride compounds the majority of fluoride added to drinking water in the US and Canada is in the form of fluorosilicic acid, sodium silicofluoride, and sodium fluoride – all industrial by-products. In the 1930s when fluoridation was first proposed it seemed like a win-win. Get rid of dangerous industrial waste and improve the health of our nations teeth. This only works if the form of fluoride being added to the drinking water is in fact not a health danger.
Is Fluoride Dangerous?
There is almost an ocean of data on the dangers of Fluoride. I'm going to focus on the effects on children of fluoridated water – in other words, normal conditions in the US. The studies are NOT about excessively high dosages leading to acute toxicity.
Fluoride and your child's brain
Fluoridation in water has been shown in human and animal studies to decrease IQ:
“We found that exposure to fluoride (F) in urine was associated with reduced Performance, Verbal, and Full IQ scores before and after adjusting for confounders. The same pattern was observed for models with F in water as the exposure variable…. The individual effect of F in urine indicated that for each mg increase of F in urine a decrease of 1.7 points in Full IQ might be expected (Rocha-Amador D, et al. (2007). Decreased intelligence in children and exposure to fluoride and arsenic in drinking water. Cadernos de Saude Publica 23(Suppl 4):S579-87.)”
“This results of this study indicate that there is significant difference between the intellectual ability of the 7 – 14 year old children from the endemic area and those of the control, and moreover that the average IQ of the children from the endemic area is clearly lower. In the endemic region, the children in the 80-89 range and below make up more than 25% of the total, while in the control range only 18% of the children fall into that range,demonstrating that high fluoride has a direct connection with the intellectual development of children (Chen YX, et al. (1991). Research on the intellectual development of children in high fluoride areas. Chinese Journal of Control of Endemic Diseases. 6(supplement):99-100.)”
Fluoride and Cancer
A large study of fluoridated cities in the US was conducted to look for correlations with a myriad of cancer types.
“cancers of the oral cavity and pharynx, colon and rectum, hepato-biliary and urinary organs were positively associated with FD (water fluoridation). This was also the case for bone cancers in male, in line with results of rat experiments. Brain tumors and T-cell system Hodgkin's disease, Non-Hodgkin lymphoma, multiple myeloma, melanoma of the skin and monocytic leukaemia were also correlated with FD (Takahashi K, Akiniwa K, Narita K. Regression analysis of cancer incidence rates and water fluoride in the U.S.A. based on IACR/IARC (WHO) data (1978-1992). International Agency for Research on Cancer. Journal of Epidemiology. 2001 Jul;11(4):170-9.)”
Fluoride and Fertility
Fluoride can cause infertility,
“A review of fluoride toxicity showed decreased fertility in most animal species studied. The current study was to see whether fluoride would also affect human birth rates. A U.S. database of drinking water systems was used to identify index counties with water systems reporting fluoride levels of at least 3 ppm. These and adjacent counties were grouped in 30 regions spread over 9 states… Most regions showed an association of decreasing TFR [Total Fertility Rate] with increasing fluoride levels (Freni SC. (1994). Exposure to high fluoride concentrations in drinking water is associated with decreased birth rates. Journal of Toxicology and Environmental Health 42:109-121.)”
Fluoride and Bone Density
“‘Skeletal fluorosis' is a condition associated with prolonged accumulation of fluoride resulting in fragile bones having low tensile strength. It affects the joints as well as the bones. It is not easily recognizable till advanced stage. In its early stages, its symptoms may resemble those of arthritis. In its most severe stages it becomes a crippling disability that has a major public health and socio-economic impact, affecting millions of people in various regions of Africa, China and India (Ayoob S, Gupta AK. (2006). Fluoride in Drinking Water: A Review on the Status and Stress Effects. Critical Reviews in Environmental Science and Technology 36:433–487.)”
Fluoride and the Thyroid
There is clear evidence that small amounts of fluoride, at or near levels added to U.S. water supplies, present potential risks to the thyroid gland…Thyroid Function: Fluoride exposure in humans is associated withelevated TSH concentrations, increased goiter prevalence, and altered T4 and T3 concentrations…The thyroid effects are associated with average fluoride intakes that will be reached by persons with average exposures at fluoride concentrations of 1-4 mg/L in drinking water, especially the children (Fluoride in Drinking Water: A Scientific Review of EPA'sStandards,” Committee on Fluoride in Drinking Water, Board on Environmental Studies and Toxicology, Division on Earth and Life Studies, National Research Council of the National Academies of Science. March 2006 Chapter 8).”
This is honestly just a sampling. There is a comprehensive list of research on the health effects of Fluoride at SLweb.
What Can You Do?
- If you have city water check the level of fluoridation. The CDC has a website called My Water's Fluoride where you can search for your city's fluoride levels. However, there didn't seem to be any data for my state at all. I did find Ohio Fluoridation levels with a Google Search.
- If you have well water have it checked for fluoride levels. The levels could be low or high as it varies from well to well even in the same area.
- Get a reverse-osmosis or activated alumina water filter. Your average Brita does not remove fluoride.
- Bottled water has fluoride in most cases. Bottled spring water is best but just because it says “spring” on the label doesn't mean it is from a spring. Besides, bottled water creates a landfill nightmare.
- If you formula feed your infant DO NOT USE FLUORIDATED TAP WATER. Reconstituted formula “contains 100 to 200 times more fluoride (1,000 ppb) than is found naturally in breast milk (5-10 ppb). In fact, while breast-fed infants receive the LOWEST body burden (mg/kg/day) in the population, they receive the HIGHEST body burden if they receive fluoridated formula (source).”
- Use a fluoride-free toothpaste, especially for children who tend to swallow enough toothpaste to exceed their daily limit.
- Don't use Teflon-coated non-stick pans. Teflon is the brand name of polytetrafluoroethylene where the “fluor” is fluoride. Even if you aren't worried about fluoride, Teflon is bad news.
This was a long post, thanks for sticking with me. It took me several weeks to combine all this material because there is just SO MUCH. If you want more information I would really recommend The Fluoride Action Network and the Environmental Working Group (search for Fluoride).