Fluoride – Good or Bad?

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Fluoride – Good or Bad?

Healthylife Pharmacy8 May 2018|4 min read

Fluoridated water has been blamed for brittle teeth, thyroid problems and lowering the average intelligence level – but government bodies insist it's good for us. Let us look at what the studies say. But first - 

What is Fluoride?

Fluoride is a natural mineral found in the earth's crust, plants, and water.  In the human body, fluoride is stored in the bones and teeth, and a small amount is found in the kidneys.

You may have heard of fluorine – this is the chemical element and anion (F-), and its pure form is a highly toxic, reactive yellow-green gas. Fluoride on the other hand, is a type of compound that contains the fluorine anion (F-) such as sodium fluoride. 

How Fluoride Strengthens Teeth & Bones

Evidence abounds that fluoride strengthens teeth.

Tooth enamel is mainly made up of a hard-wearing mix of calcium and phosphate called hydroxyapatite. When anything acidic comes in contact with the teeth (including saliva), calcium gets stripped away, dissolving the tooth. But with an ideal range of fluoride available, fluoride binds to the hydroxyapatite and creates a harder wearing material called fluorapatite, which resists decay [5]. 

This also occurs in bones throughout the body, where fluroapetite strengthens the bones against breakages.

Inadequate fluoride intake results in brittle bones, frequent fractures, increased tooth decay, and possibly osteoporosis

Fluoride in the Water

In an effort to prevent tooth decay, local water supplies can add fluoride to what has been deemed a safe and beneficially level. In Australia, the National Health and Medical Research Council  supports local councils throughout Australia adding fluoride to their drinking water supplies within a range of 0.6 to 1.1 milligrams of fluoride per litre [10].

This practice has been going on, worldwide, since the 1940s. Has it worked? Maybe... The conclusions are mixed. While public health bodies insist that dental health has improved as a result of water fluoridation, a Cochrane review of 155 studies stated that there is insufficient evidence to conclude that the use of fluoride in drinking water prevents dental caries, particularly in adults [7]. The authors mentioned that the effects of fluoride from toothpaste may be just as effective, and that there is a significant link between fluoride in drinking water and an increased risk of health problems:

Health Risks of Too Much Fluoride

Dental Fluorosis occurs when children ingest too much fluoride for a long period of time, before the age of 7.

The teeth first show signs of mottled enamel, and then become hard and brittle, with pitting across the surface of the teeth. Some studies suggest that use of fluoridated toothpastes in this age group can also contribute to fluorosis [8], but the Australian Dental Association disagrees and recommends that children's teeth should be cleaned twice a day with toothpaste containing 0.5–0.55 mg/g of fluoride (500–550 ppm).

Skeletal Fluorosis is caused by chronic, excessive fluoride ingestion leading to damage of tendons, ligaments and joint capsules. Early symptoms include:

  • Aches that are vague and diffuse – you can't quite place where they are
  • Chronic fatigue
  • Joint stiffness
  • Decreased range of movement

In later stages, calcification of the bones occurs and can cause osteoporosis, osteosclerosis, or kyphosis [3].

Thyroid Problems

The thyroid gland creates hormones that regulate a wide range of physiological functions, including metabolic rate, temperature, heart rate, reproductive cycles and blood pressure. It is capable of absorbing and accumulating fluoride, which can cause significant damage to the gland's tissues and impair its functions. Studies have shown that drinking water with a concentration of 0.5mg of fluoride per litre can significantly disrupt thyroid function [6] – that's much less than the accepted 1.1mg per litre found in Australian fluoridated water!

Childhood Intelligence

A 2016 study examined the IQ levels of 10 – 12 year old children and the fluoride levels in their drinking water over a 3 month period. The researchers found that children with higher IQ consumed much less fluoride in their drinking water  [11] – but keep in mind that this study's design was limited by many factors. A prospective trial in New Zealand found that there was no association between IQ and fluoride intake [12], while a meta-analysis concluded that children who live in a fluorosis area are five times more likely to develop a low IQ than those who do not [13].

Other Issues Associated with Excessive Fluoride:

  • Osteoporosis
  • Hypertension
  • Diabetes mellitis
  • Obesity [3] [4]

Fluoride in Toothpaste

Any type of acid in the mouth (including saliva) breaks down the calcium ions and weakens teeth, leading to caries. A recent study showed that fluoride from toothpaste is able to strengthen the hydroxyapatite against these reactions by sticking firmly to calcium ions, anchoring them together and reducing the rate at which the tooth is worn down [1]. But there's a catch – the fluoride ions barely penetrate into the tooth, and are quickly worn away with chewing and movement, which is why fluoride needs to be frequently reapplied by brushing daily with a fluoridated paste.

Fluoride from toothpaste isn't absorbed into the body through the teeth – it stays in the enamel. If you're worried about fluorosis, make sure you do a thorough rinse-and-spit after brushing and don't swallow any toothpaste!

Dietary Sources of Fluoride

Tea is a rich source of fluorine compounds, and drinking one litre of tea per day can supply the recommended daily intake of 4mg of dietary fluoride – that may be a bit risky if you're also using fluoridated water. Heavy tea drinkers are at risk of skeletal and dental fluorosis, leading to breakages and caries.

Aside from tea, other major sources of fluoride in the diet include shellfish, wine, potato chips and beer [2].

How to Reduce Fluoride Intake

Invest in a Good Quality Water Filter – Reverse osmosis, deionizers and activated alumina are the three types of water filters that can remove fluoride from water. Bench-top activated charcoal filters do not remove fluoride. [7]

Avoid Cooking with Non-Stick Teflon Pans. Stainless steel is a good alternative that won't leech fluoride into your food. [14]

Reconsider Eating Chicken – Pre-cut chicken meat has often been mechanically separated from the bones, a process that often releases fluoride from the bones into the meat [15].

Buy Organic Wine – Wine's high fluoride content is mostly due residue from a pesticide used on non-organically farmed grapes [16].

Eat Fresh Food – Processed foods contain much higher amounts of fluoride than fresh fruits, vegetables, legumes and nuts [2].

References

  1. de Leeuw, N. H. Resisting the Onset of Hydroxyapatite Dissolution through the Incorporation of Fluoride. Journal of Physical Chemistry B, published online, doi:10.1021/jp036784v (2004). https://www.researchgate.net/publication/231637522_Resisting_the_Onset_of_Hydroxyapatite_Dissolution_through_the_Incorporation_of_Fluoride
  2. USDA (2017) Food Composition Database – Fluoride. https://ndb.nal.usda.gov/ndb/nutrients/report/nutrientsfrm?max=25&offset=0&totCount=0&nutrient1=313&nutrient2=&subset=0&sort=c&measureby=g
  3. Kurdi, M. S. (2016) Chronic fluorosis: The disease and its anaesthetic implications. Indian J Anaesthetic., 60:3, 157 – 162. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4800930/#ref18
  4. Balasubramanyam, M., Lenin, R. & Monickaraj, F. (2010) Endoplasmic reticulum stress in diabetes: New insights of clinical relevance. Indian J Clin Biochem., 25:2, 111 – 118. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3453102/
  5. Everett, E. T. (2011) Fluoride’s Effects on the Formation of Teeth and Bones, and the Influence of Genetics. J Dent Res., 90:5, 552 – 560. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3144112/
  6. Kheradpisheh, Z., et al. (2018) Impact of Drinking Water Fluoride on Human Thyroid Hormones: A Case- Control Study. Scientific Reports, 8:2674.
  7. https://www.nature.com/articles/s41598-018-20696-4
  8. Jaafari-Ashkavandi, Z. & Kheimand, M. (2013) Effect of home-used water purifier on fluoride concentration of drinking water in southern Iran. Dent Res J., 10:4, 489 – 492. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3793412/
  9. Mascarenhas, A. K. & Burt, B. A. (1998) Fluorosis risk from early exposure to fluoride toothpaste. Community Dent Oral Epidemiol., 26:4, 241 – 248. https://www.ncbi.nlm.nih.gov/pubmed/9758424
  10. Australian Dental Association (n.d.)Policy Statement 2.2.1 – Community Oral Health Promotion: Fluoride Use (Including ADA Guidelines for the Use of Fluoride).  https://www.ada.org.au/Dental-Professionals/Policies/National-Oral-Health/2-2-1-Fluoride-Use/ADAPolicies_2-2-1_FluorideUse_V1
  11. National Health and Medical Review Council (2017) 2017 Public Statement – Water Fluoridation and Human Health in Australia. https://www.nhmrc.gov.au/guidelines-publications/e44-0
  12. Avarind, A., et al. (2016) Effect of fluoridated water on intelligence in 10-12-year-old school children. J Int Soc Prev Community Dent., 6:3, S237 – S242. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5285601/
  13. Broadbent, J. M., et al. (2015) Community Water Fluoridation and Intelligence: Prospective Study in New Zealand. Am J Public Health., 105:1, 72-76. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4265943/
  14. Tang, Q. Q., et al. (2008) Fluoride and children's intelligence: a meta-analysis. Biol Trace Elem Res., 126:1-3, 115 – 120. https://www.ncbi.nlm.nih.gov/pubmed/18695947
  15. Füchtner, F., et al. (2008) Factors affecting the specific activity of [18F]fluoride from a [18O]water target. Nuklearmedizin., 47:3, 116 – 119. https://www.ncbi.nlm.nih.gov/pubmed/18493691
  16. Jedra, M., et al. (2001) [Bioavailable fluoride in poultry deboned meat and meat products]. Rocz Panstw Zakl Hig., 52:3, 225 – 230. https://www.ncbi.nlm.nih.gov/pubmed/11771115
  17. Goschorska, M., et al. (2016) Fluoride Content in Alcoholic Drinks. Biol Trace Elem Res., 171, 468 – 471. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4856716/