‘Pie hole’, colloquial for one’s mouth, is believed to have evolved in the USA in the 1980s from the British expression ‘cake hole’ (coined in the mid 20th century). Pie hole refers to a mouth, as in: Shut your pie hole or, in this case: Put less in your pie hole.

Wednesday, February 18, 2015

Flip-Flopping on Water Fluoridation

Something not many of us think about anymore is fluoride as an additive in water. Is it mind control? Or something more sinister? New research and reviews show that water fluoridation may not be just a playground for conspiracy theorists. Evidence shows fluoridating water doesn't improve dental issues and actually causes several health problems... Something worthy to sink our teeth into.

A few students in my class this semester brought up their concerns about water fluoridation (WF). Given there have been no big exposé articles in the media and no notable research articles from my dietitian news alert, I dismissed it... Until the nagging voice in my head lead me to investigate it myself. What I found surprised me...

Before we get to the root of the problem, a little about fluoride: It is widely distributed in the environment, occurring in the air, soils, rocks, and water. It is found in tea and some grains (therefore many cereal products) and foods/beverages processed with water that is fluoridated.
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In 1945 water supplies were first fluoridated for the medicinal purpose of preventing dental caries (commonly known as cavities or decay) in a Michigan city. WF was widely introduced at 1 ppm during the 1950s. This was when evidence* showed a reduction in dental caries with WF.

*Many scientists would like to note this widespread introduction was based on research that was later highly criticised for methodological flaws and selection bias.

Newer research shows no difference in dental caries between children drinking fluoridated vs non-fluoridated water. Many other countries followed the US and introduced WF, but in recent years have dropped the scheme due to concerns about safety and effectiveness.

Fluorosis occurs with the overconsumption of fluoride and ranges in severity from minor tooth discolouration to severe discolouration (more info here). In areas where WF exists, the incidence of fluorosis has increased. One of the many problems with WF is that the dose is widely variable depending on how much water is consumed.

The effectiveness of WF is controversial. Here's some background and evidence I drilled out earlier:
  • Tooth hydroxyapatite (the rigid matrix structure of bone and teeth) consists of calcium, magnesium, and phosphate. It is susceptible to decay induced by acid-producing bacteria. Fluoride interacts with hydroxyapatite to form fluoroapatite, which is less susceptible to erosion by acid-producing oral bacteria
  • However, much research shows fluoride is effective at preventing dental decay only by topical application eg: toothpaste, not drinking fluoridated water
  • Research shows the amount of fluoride found in water is unable to influence teeth caries, with the fluoride concentration in toothpaste being over 75,000 times greater than in water (and toothpaste is generally not swallowed/consumed)
Further, the remineralisation process is not dependent on fluoride. In fact, the calcium and magnesium content of tooth enamel are more important to fluoride's anticaries effect. This is concerning for individuals who are undernourished - in America about 1% of children are malnourished.

Excessive and prolonged fluoride consumption has been shown to increase development of certain cancers, hypothyroidism, negatively affect IQ in children and increase incidence/severity of dental fluorosis.

Dental caries are caused by physical, biological, environmental, behavioural, and lifestyle-related factors including:
- Bacteria
- Inadequate saliva
- High intake of carbohydrates and sugars
- Low access to dental services
- Poor oral hygiene 
- Malnutrition (particularly calcium and magnesium) and poverty

  • There is substantial evidence showing the minor benefits of WF do not outweigh the negative effects
  • Given the questionable evidence supporting WF for the prevention of dental caries, the policies surrounding WF require radical review and rethinking
  • Implementing targeted oral health interventions combined with community-wide awareness and education are more favourable fixes to fill the fluoridation fallout