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A Clinician's Guide To Fluoride

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Flouride - how bad is it?

Fluorine is a naturally occurring element that does not often exist on its own in nature due to its high reactivity. Instead, fluorine is often bonded to other elements to make it into a fluoride compound. It is these fluoride compounds that we colloquially know as “fluoride”.
 
As you can imagine, there are multiple elements that can be bound to fluorine to make the fluoride compounds. For the purpose of keeping this article clinically relevant, the discussion focuses on the fluorides commonly found in our environment and ones in which we can encourage our clients to avoid to positively effect health outcomes and minimise risks associated with high fluoride exposure.
 
The three most common fluoride compounds are sodium fluoride (NaF), calcium fluoride (CaF2) and fluorosilicic acid (H2SiF6). NaF and CaF2 are primarily found in toothpaste, dental treatments and mouthwash. Whereas drinking water in Australia can contain NaF, H2SiF6 and sodium silicofluoride (Na2SiF6).[1,2]
 

Why is fluoride used?

Fluoride is primarily known for its effect in decreasing tooth decay by strengthening the enamel and there is indeed adequate research to support this, particularly with topical application of fluoride.[3,4]
 
However, despite this mechanism of action, tooth decay is still considered to be a significant problem in Australia and one that water fluoridation has obviously not resolved. 
 
Interestingly, fluoridation of the water supply is banned in Europe and there are no higher rates of tooth decay there compared to what we face here in Australia. 
 

Sources of fluoride 

When fluoridation of our water supply came into affect during the 1950s there was much less fluoride exposure from other sources. Fast forward to our current situation, we now see several significant sources of fluoride exposure prevalent in our environment, many of which are daily assaults to our system:
 
  • Dental products such as toothpaste and mouthwash, with an average fluoride content of 1-1.5mg/g in commercial fluoride toothpastes 
  • Many processed food and drinks
  • Some pharmaceutical medications
  • Meat that uses a mechanically deboning processes 
  • Pesticides 
  • Teflon cookware
  • Industrial workspaces 
  • Tea consumption (green, black, white, iced tea)
  • Exposure during certain dental procedures
  • Drinking water (including filtered water unless specifically designed to remove fluoride) 

Dangers of fluoride

Fluoride crosses into the placenta[5] allowing the developing brain to be exposed to fluoride, which has the potential to influence neurological development.[6]  
 
In 2014, Harvard researcher Phillippe Grandjean classified fluoride as a developmental neurotoxicant based on over 27 studies assessing fluoride's impact on IQ.[7]
 
Studies have shown that children living in high-fluoride areas had significantly lower IQ scores than those who lived in low-fluoride areas.[8] Although the levels that children were exposed to in the high fluoride levels from drinking water were higher than the contents of fluoridated water in Australia, we have to recognise that tap water is just one of the many sources of fluoride we now have in our environment which is likely having a cumulative effect. 
 
We also need to recognise that fluoridation of the water supply is essentially giving the same dose of “medication” to every individual in a population. A far cry from patient-centred, individualised medicine that should guide best practise. 
 
The neurotoxic effects of excess fluoride exposure does not stop in utero. There is also evidence to suggest a link with conditions such as dementia, Alzheimer's, depression and sleep disorders. Some examples of the mechanism by which fluoride affects neurological health include damage to the hippocampus, increase in oxidative stress, reduced nicotinic receptors, alterations in protein expression and neuronal degeneration.[9-11]
 
In addition to its potential neurotoxicity, fluoride can also contribute to hypothyroidism via its ability to mimic the action of thyroid stimulating hormone (TSH).[12] In the United Kingdom (UK), research comparing hypothyroidism rates in fluoridated communities versus non-fluoridated communities showed that hypothyroidism was 1.6 times higher in fluoridated communities.[13
 
The amount of fluoride being added to the water supply in the UK is 0.7mg/L which is actually very similar to that of Australian fluoridated communities. And while high fluoride exposure is not likely the root of all hypothyroidism, it is a worthwhile consideration and something that we as practitioners can make a significant difference to by encouraging our patients to use filtered water and fluoride-free dental care products where indicated.
 

Fluoride antagonists


As with all elements, compounds and nutrients alike, there is often both an agonist and an antagonist. This is important clinically to understand, allowing us to use them to our advantage. 
 

Iodine 

Both fluoride and iodine belong to the chemical class known as halogens, which are goitrogens. Fluoride competes with iodine for uptake into the thyroid gland and therefore can contribute to the development of hypothyroidism. In fact, historically, fluoride has been used in the treatment of hyperthyroidism at a dose of 0.9-4.2mg per day. To put that into context, most people exposed to fluoridated drinking water get 1.6-6.6mg/day, depending on location and water intake.[14
 

Calcium 

Calcium has a strong affinity for fluoride and perhaps this is best demonstrated by the body’s own sequestration of fluoride into calcified tissues, such as bones and teeth. In fact, in China, where dental fluorosis is a significant problem, porous bone char is one of the absorbent mediums used in defluoridation plants used to remove fluoride from water.
 

Aluminium

Aluminium is a strong antagonist for fluoride and is sometimes used to remove fluoride from drinking water. However, due to aluminium's negative effects on human health it is arguably a very poor option for therapeutic use.[15]
 

Magnesium 

Magnesium, a mineral involved in over 300 enzymatic reactions in the body, is another antagonist for fluoride. In fact, research has shown that a low magnesium-containing diet resulted in significantly more fluoride in the bones and teeth.[16]
 

Signs of deficiency and excess

Contrary to popular belief, fluoride is not an essential nutrient. According to the Centre for Disease Control “The prevalence of dental caries in a population is not inversely related to the concentration of fluoride in enamel, and a higher concentration of enamel fluoride is not necessarily more efficacious in preventing dental caries.”[17] Likewise the National Research Council has also concluded that fluoride is not an essential element.[18
 
So with this in mind, are there symptoms we can conclude are from a fluoride deficiency? Probably not. However, as mentioned previously, there is substantial research to support that topical application of fluoride can be helpful in the treatment of dental caries. Therefore it is inaccurate to say that it never has a benefit or application.
 
Systemic fluoride excess can manifest as:
 
  • brittle bones
  • bone fractures
  • skeletal fluorosis (pain and damage to bones and joints)
  • dental fluorosis (mottled tooth enamel)
  • impaired glucose metabolism
  • skin rashes
  • hypothyroidism
  • neurological changes.
Clearly many of these symptoms are somewhat nonspecific and could be attributed to several causes, however fluoride excess is indeed one such cause that should be investigated and addressed as part of holistic treatment of patients.  
 

Detoxing from fluoride

As with many endeavours to improve our clients’ health, it is important to educate them on how they can control their exposure. Encouraging patients to use a water filter, switch to fluoride-free dental care products and be aware of the presence of fluoride in commercial food, beverages (such as tea) and certain medications. 
 
Of course this advice needs to be analysed and delivered with a cost versus benefit analysis. We don’t need to create neurotic behaviour, but rather awareness and encouragement to make informed decisions and prioritise removing the largest sources of fluoride in someone's environment where indicated. 
 
Beyond this, there are natural detoxifying agents that may be of benefit for those showing signs of toxicity.
 

Magnesium and iodine

As mentioned previously, both magnesium and iodine are safe and effective antagonists to fluoride. Magnesium inhibits the absorption of fluoride into the cells and iodine competes for absorption with fluoride into the thyroid gland.
 

Tamarind

Tamarind has a strong traditional use in Ayurvedic medicine. Some studies have shown that tamarind consumption increases the excretion of fluoride into the urine. Researchers have concluded that tamarind may therefore be an effective detoxifying agent when it comes to high fluoride exposure.[19,20]
 

GABA

Preliminary research has demonstrated the protective effects of gamma-aminobutyric acid (GABA) against fluoride-induced toxicity.[21]
 

Taurine


Research has shown that taurine can ameliorate thyroid dysfunction in rats chronically exposed to fluoride.[22]
 

Selenium

Selenium supplementation provides antioxidant support and assists in reducing oxidative damage from high fluoride exposure.[23-25]
 

Glutathione


Glutathione is critical to optimising detoxification capabilities in the body and in the regeneration of several key antioxidants. Chronic fluoride exposure results in decreased glutathione levels,[26] therefore supplementation can be of benefit. 
 

Curcumin


Fluoride exposure can increase lipid peroxidation and increase neurodegeneration. Supplementation with curcumin for 30 days significantly decreased lipopolysaccharides and neurodegeneration compared with the control group receiving fluoride alone.[27] Given curcumins relative safety and broad reaching health benefits it should be a consideration in the removal of fluoride. 
 

Final thoughts

So where does that leave us on the fluoride debate? Should we dismiss all use of fluoride? Probably not just yet. Given the clear benefits from targeted and appropriately used topical application it would be inaccurate to conclude that it doesn't have its place. However, given the vast research on the potential dangers of fluoride, it is unlikely that chronic systemic exposure to the now multiple sources of fluoride in our environment is without significant detriment to individuals and should be a key consideration in providing holistic, patient-centred care.
 

REFERENCES

  1. Product safety summary: fluorosilicic acid Solvay America Inc. 2010-2012, http://www.solvaynorthamerica.com/SiteCollectionDocuments/PDF/PS_Fluoros...
     
  2. Water fluoridation questions and answers. NSW Health 2015, http://www.health.nsw.gov.au/environment/water/Documents/fluoridation-qu...
     
  3. Featherstone JDB. Prevention and reversal of dental caries: role of low level fluoride. Community Dent Oral Epidemiol 1999;27:31-40. [Abstract]
     
  4. Koulourides T. Summary of session II: fluoride and the caries process. J Dent Res 1990;69(special issue):558.
     
  5. Agency for Toxic Substances and Disease Registry. Toxicological profile for fluorides, hydrogen fluoride, and fluorine. US Department of Health and Human Services 2003, http://www.atsdr.cdc.gov/toxprofiles/tp11.pdf 
     
  6. Grandjean P, Landrigan P. Developmental neurotoxicity of industrial chemicals. Lancet 2006;368(9553):2167-2178. [Abstract]
     
  7. Grandjean P, Landrigan PJ. Neurobehavioural effects of developmental toxicity. Lancet Neurol 2014;13:330-338. [Full text]
     
  8. Choi AL, Sun G, Zhang Y, Grandjean P. Developmental fluoride neurotoxicity: a systematic review and meta-analysis. Environ Health Perspect 2012;120:1362-1368. [Full text]
     
  9. Lou DD, Zhang KL, Qin SL, et al. Alteration of mitochondrial distribution and gene expression of fission 1 protein in cortical neurons of rats with chronic fluorosis. Zhonghua Bing Li Xue Za Zhi 2012;41(4):243-247. [Abstract]
     
  10. Liu YJ, Guan ZZ, Gao Q, et al. Increased level of apoptosis in rat brains and SH-SY5Y cells exposed to excessive fluoride–a mechanism connected with activating JNK phosphorylation. Toxicol Lett 2011;204(2-3):183-189. [Abstract]
     
  11. Kaur T,Bijarnia RK, Nehru B. Effect of concurrent chronic exposure of fluoride and aluminum on rat brain. Drug Chem Toxicol 2009;32(3):215-221. [Abstract]
     
  12. Chandna S, Bathla M. Oral manifestations of thyroid disorders and its management. Indian JEndocrin Metab 2011;15(Suppl2):S113-S116, http://doi.org/10.4103/2230-8210.8334.
     
  13. Peckham S, Lowery D, Spencer S. Are fluoride levels in drinking water associated with hypothyroidism prevalence in England? A large observational study of GP practice data and fluoride levels in drinking water. J Epidemiol Community Health  2015;69(7):619-624. [Abstract]
     
  14. Wentz I. Fluoride and your thyroid. ThryoidPharmacist.com 2015, https://thyroidpharmacist.com/articles/fluoride-and-your-thyroid/ 
     
  15. Spencer H, Kramer L, Norris C, et al. Effect of aluminum hydroxide on plasma fluoride and fluoride excretion during a high fluoride intake in man. Toxicol Appl Pharmacol 1989;58:140-141. [Abstract]
     
  16. Cerklewski FL. Influence of dietary magnesium on fluoride bioavailability in the rat. J Nutr 1987;117:(3):496-500. [Abstract]
     
  17. Department of Health and Human Services Centers for Disease Control and Prevention (CDC). Recommendations for using fluoride to prevent and control dental caries in the United States. Mortality Morbidity Weekly Rev 2001;50(RR14):1-42. [Full text]
     
  18. National Research Council. Health effects of ingested fluoride. National Academy Press: Washington DC, 1993. [PDF]
     
  19. Khandare AL, Kumar PU, Shanker RJ, et al. Additional beneficial effect of tamarind ingestion over defluoridated water supply to adolescent boys in a fluorotic area. Nutrition 2004;20:433-436. [Abstract]
     
  20. Khandare AL, Rao GS, Lakshmaiah N. Effect of tamarind ingestion on fluoride excretion in humans. Eur J Clin Nutr 2002;56:82-85. [Abstract]
     
  21. Yang H, Xing R, Liu S, et al. γ-aminobutyric acid ameliorates fluoride-induced hypothyroidism in male Kunming mice. Life Sci 2016;146:1-7. [Abstract]
     
  22. Adedara IA, Ojuade TJD, Olabiyi BF, et al. Taurine ameliorates renal oxidative damage and thyroid dysfunction in rats chronically exposed to fluoride. Biol Trace Elem Res2017;175(2):388-395, https://www.ncbi.nlm.nih.gov/pubmed/27334436
     
  23. Zhang Z, Shen X, Xu X. Effects of selenium on the damage of learning-memory ability of mice induced by fluoride. Wei Sheng Yan Jiu 2001;30:144-146. [Abstract]
     
  24. Basha MP, Sujitha NS. Chronic fluoride toxicity and myocardial damage: antioxidant offered protection in second generation rats. Toxicol Intern 2011;18(2):99-104, http://doi.org/10.4103/0971-6580.84260 
     
  25. Chen Q, Wang Z, Xiong Y, et al. Selenium increases expression of HSP70 and antioxidant enzymes to lessen oxidative damage in Fincoal-type fluorosis. J Toxicol Sci 2009;34(4):399-405. [Abstract]
     
  26. Kaushik T, Shyam R, Vats P, et al. Glutathione metabolism in rats exposed to high-fluoride water and effect of spirulina treatment. Fluoride 2001;34(2):132-138. [Full text]
     
  27. Sharma C, Suhalka, P, Sukhwal P, et al. Curcumin attenuates neurotoxicity induced by fluoride: An in vivo evidence. Pharmacognosy Mag 2014;10(37):61-65, http://doi.org/10.4103/0973-1296.126663

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Natalie Bourke

Natalie is a holistic dietitian and nutritionist, author, podcaster, speaker and fitness instructor. She is part of the practitioner support team at one of Australia's leading providers of therapeutic supplements and runs Health By Whole Foods, a nutritional consulting business with a clinical focus on thyroid dysfunction, HPA axis dysregulation (or “adrenal fatigue”), and gut health.  Nat is passionate about helping women build a healthy relationship with food and their body; she achieves lasting results for her clients using whole food nutrition, functional medicine and holistic lifestyle advice. You can catch her fortnightly on The Holistic Nutritionists Podcast, with fun and quirky interviews that aim to dispel nutrition myths and guide listeners on a balanced approach to health. Her eBook, Healing Digestive Discomfort, is an industry-leading guide with accessible guidance for anybody looking to start improving their gut health.