Hard to swallow

It’s been one of the quietest retreats in modern medical history. From being the pioneer and champion of adding fluoride to public water, the US has dramatically reduced the levels that are permissible, effectively ending the practice in many regions – and it could signal the beginning of the end of a public-health policy that has been almost universally rejected.

It’s a remarkable reversal by a country that, in 1951, was the first to adopt fluoridation, designed to prevent dental decay in children, and which its Centers for Disease Control and Prevention (CDC) designated as one of the 10 greatest public-health achievements of the 20th century.

The policy shift, announced by the US Department of Health and Human Services, reduces the safe level of fluoride in public water from 1.2 mg/L of water to just 0.7 mg/L. As mineral deposits are a natural source of fluoride in drinking water, many areas will have to stop artificial fluoridation to stay within the new limits. Before the new guidelines were announced last year, 42 of the 50 States had artificial fluoridation, reaching 74 per cent of the population through public-water systems.

This leaves only the Republic of Ireland, Singapore and Australia with any semblance of a national fluoridation programme, and even these are under attack. Some 30 other countries around the world still have areas with fluoridation, and it’s been estimated that just over 5 per cent of the world’s population are drinking public water that’s been artificially fluoridated.

Teething problems

The new lower limits in the US were set after a CDC study found that 40.7 per cent of 12- to 15-year-old adolescents had dental fluorosis, or mottled enamel, an unsightly and permanent discolouring of the teeth due to excessive fluoride exposure.

But over the years, scientists have discovered something much more worrying about fluoride. Recognized as a neurotoxin, there seems to be a connection between fluoride and brain development and learning disabilities. Also, because 50 per cent of the fluoride we ingest settles in our bones, there’s a link between it and bone and joint disease, and even bone cancer.

Fluoride may be one way to prevent tooth decay in children – although an independent Cochrane review couldn’t conclusively establish this as fact – but only when it’s spread on and around the tooth, not when it’s digested when we drink water.

Skeletal fluorosis, a disease of the bones and joints, is caused by excessive accumulation of fluoride. It’s a serious problem in China, India and the Rift Valley in Africa, where there are already dangerously high levels of fluoride in the public water from natural sources. Around 30 million Chinese suffer from skeletal fluorosis, and artificial fluoridation has been banned there and in India, where the condition is endemic in 20 states.

Brain developmental and learning problems are thought to be connected to exposure to fluoride. One review of 27 published papers found that children living in high-fluoridation areas in China had lower IQ scores than children exposed to lower levels. On average, their scores were around 45 per cent lower.1

Hypothyroidism, or an underactive thyroid gland, seems to be associated with levels of fluoride in the water supply. Doctors working in areas of the UK with artificial fluoridation have noticed a high prevalence of hypothyroidism. From case reports surveyed in 2012 and 2013, doctors with surgeries in the UK’s West Midlands region, an area that fluoridates its water, reported twice the number of patients with hypothyroidism compared with Greater Manchester, which doesn’t fluoridate.

Fluoride is a “contributing factor” to hypothyroidism, the researchers concluded.2

Male fertility could also be affected by excessive fluoride exposure. One study with laboratory rats found that fluoride interfered with the health of sperm, and caused severe abnormalities in the testes.3

Bone cancer (osteosarcoma) seems to be caused by fluoride, although the story surrounding the discovery is up there with other great medical conspiracies. It’s been a controversial subject, with evidence of a link refuted by another study, yet a definitive connection seemed to have been established in a doctoral dissertation by Harvard School of Dental Medicine student Elise Bassin, submitted in 2001. After studying 103 cases of osteosarcoma in those under age 20, and comparing their childhood exposure to fluoride against 215 healthy controls of similar ages, she found that men were five times more likely to develop the cancer as young adults if they’d been exposed to the supposed ‘safe’ levels of fluoride at age seven, apparently the most vulnerable age.

For years, Harvard kept the paper under lock and key: people were allowed to view it – but not take a copy of it – only in the presence of a Harvard library staff member. It was eventually published,4 although Bassin has since asked for it to be withdrawn. It was later revealed that the Dental School had received a $1 million donation from a major toothpaste manufacturer that used fluoride in its products.

The whole tooth

All this may seem a price too high to pay for a public-health experiment – as many of its detractors describe it – that’s supposed to prevent tooth decay in children. And although there is some evidence of its benefits, an analysis by the independent Cochrane Collaboration questions even that cherished belief.

The Cochrane reviewers looked at 20 studies investigating the impact that water fluoridation on tooth-decay levels; most of the studies were positive, with a 35 per cent reduction in cases of tooth decay. But the reviewers were concerned about the quality of the work in almost every case, and concluded there is not enough good evidence to determine one way or the other whether fluoride is effective. In any case, fluoridation at 0.7 mg/L – when the current standard level in the UK is 100 mg/L – produced serious fluorosis in 12 per cent of children, while 40 per cent of children were affected to some extent.5

American researchers are more emphatic. In one study of around 39,000 children, artificial fluoride prevented decay in just 0.6 of a tooth surface but, as there are more than a hundred tooth surfaces in the average mouth, such a benefit is insignificant.6

A survey that looked at tooth decay among children in Bedford – a UK town that stopped fluoridating its water – found there was only a marginal difference between children in 2008, when the town fluoridated, and in 2015, when it had stopped doing so.7

With so much evidence of harm and so little showing real benefits, public-health authorities are caught in a dilemma. Some experts, like Stephen Peckham, director and professor of health policy
at Kent University, believe it’s time to call a moratorium.

“Water fluoridation was implemented before statistics had been compiled on its safety or effectiveness,” he says. “It was the only cannon shot they had in their armoury, but it’s a dental health policy that’s got up a head of steam and people have been reluctant to see it criticized.”

How it all began

In 1901, Colorado dentist Frederick McKay noticed that many patients had permanent stains, or ‘mottled enamel’, on their teeth – but they also had less decay. McKay thought the phenomenon had something to do with the public water supply.

A few years later, Arkansas dentist F.L. Robertson started noticing something similar happening after a deep well was dug to provide public water. In 1930, a local chemist was able to establish that the water had very high concentrations of fluoride that had seeped in from the surrounding soil.

The first experiments in artificially adding fluoride to the water supply started in 1945, in towns in Michigan, New York and Illinois. Early studies found that fluoridation reduced the rate of dental decay by between 50 and 70 per cent com
pared with non-fluoridated areas.

Industry was quick to exploit the opportunity, and fluoride was added to toothpaste, gels, mouth rinses, tablets and drops.

But later studies were less positive. By the mid-1980s, the rate of tooth decay in fluoridated areas was just 18 per cent lower than in non-fluoridated regions.

Despite the sea of fluoride we’re subjected to, whether we like it or not, the vast majority of children and adolescents in the US have tooth decay. Among 12- to 17-year-olds, the rate of tooth decay is 67 per cent, and rises to 94 per cent in 18-year-olds.

Don’t drink the water

If you live in an area that fluoridates the public
water supply, what can you do to reduce your exposure? Short of not drinking the water, there are a few things you can do (and one that won’t work).

You can:

• Filter your tap water – the best way is to use a reverse osmosis filter

• Use fluoride-free water for infant formula

• Use fluoride-free toothpaste, such as Tom’s of Maine or Weleda

You can’t:

• Use bottled water, as nearly half of all bottled water is sourced from municipal tap water!

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