Is fluoride really effective in preventing tooth decay, or could it be doing us more harm than good?

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Most of us put our trust and faith in fluoride to help prevent tooth decay. It is a common ingredient in toothpaste and mouthwashes, and several countries, including parts of the UK, even add fluoride to the water supply. Even last month, a study was published which reported that adding fluoride to table salt had reduced dental decay in Jamaica. However, not all scientists are as enthusiastic about fluoride as you might imagine. Quite recent evidence suggests that fluoride is not as effective in preventing tooth decay (also known as dental caries) as was originally thought. In fact, it is now that fluoride treatment has the capacity to cause dental disease. There is also some evidence that fluoride may increase the risk of other health issues including weakened bones and thyroid disease. So, is fluoride really effective in preventing tooth decay, or could it be doing us more harm than good?

Fluoride is a by-product of certain manufacturing practises (primarily the phosphate fertiliser industry). Precisely what lay behind the decision to add it to water supplies is not clear. Fluoride is, after all, a potentially toxic waste product. Also, when fluoridation of water started some 60 years ago, there was no good evidence to suggest that fluoride might prevent tooth decay. However, partly as a result of later studies which suggested that fluoride might have some tooth-protecting qualities, fluoridation of water became accepted practice in several countries around the World. However, it is now recognised that the initial studies on fluoride and tooth decay were of poor quality from a scientific standpoint. More recently, the UK Government commissioned a review of the scientific literature on fluoride and dental caries. The results of this review, commonly referred to as the ‘York study’ was published last year in the British Medical Journal.

The York study has cast serious doubt on the usefulness of water fluoridation. As expected, the authors of the study concluded that the rationale behind the fluoridation of water is based on weak scientific evidence. In addition, the York study found that the protection offered by fluoride is much less than previously thought. In fact, just one in six people drinking fluoridated water benefits from this practice. Other studies show similarly poor results. In the largest dental health survey ever conducted in the United States, (as determined by the National Institute of Dental Research), fluoridation of water was found to protect less than 1 p.c. of the total tooth surfaces in a child’s mouth. What is more, studies conducted in Finland, East Germany, Cuba, and Canada have found that the rate of dental decay does not increase when communities stop fluoridation.

And while the benefits of fluoride appear to been grossly overrated, it seems that the hazards of this substance have been downplayed. For instance, the York study found that almost 50 p.c. of individuals drinking fluoridated water exhibit a condition known as ‘dental fluorosis’ ” a mottling of the teeth thought to be caused by the toxic effects of fluoride. So, while fluoridation of water may prevent dental disease in about 15 p.c. of the population, it seems to cause dental disease in about half those treated. And, because fluoride in water gets into the body, it is probably reasonable to assume that if toxic effects are seen in the teeth, damage is also done inside the body.

The authors of the York study stated that they could find no good evidence for the toxic effects of fluoride on the body. However, the reality is that there is at least some evidence to suggest that fluoride can have a range of undesirable effects on the body. More than one study shows that fluoride has the capacity to weaken the bones and increase the risk of fracture. There is also evidence that fluoride can accumulate in the pineal gland, a small gland in the brain which secretes the sleep-inducing hormone melatonin. Potentially, this could disrupt a range of body processes including sleep. Studies in animals show that fluoride may bring on premature puberty. Fluoride is also known to reduce the function of the thyroid gland (the organ responsible for regulating the speed of the metabolism).

One other question which hangs over the concept of fluoridation is whether this practice is ethical. After all, if fluoride does indeed reduce dental caries, should it not be classed as a medicine? If this is the case, then individuals who live in areas where the water is fluoridated are essentially being medicated without their consent. This, surely, is an infringement of human liberty. One might even question whether fluoridation of water is even legal. In English law, medical treatment without consent is only legally permitted for convicted criminals, the mentally ill, and children with the express permission of their guardians. It is interesting to note that in Scotland, fluoridation of water was deemed unlawful in 1983.

Fluoridation of water is essentially mass-medication without consent. When we as doctors prescribe drugs, we generally do so with knowledge of the patient’s sex, age, weight, medical history and current drug therapy. We also will attempt to make some judgement about whether a treatment is necessary. And even if we do suggest treatment, we will want to decide on an appropriate dosage, and monitor the effects, both good and bad. None of this is true in the case of water fluoridation. Bearing in mind the question marks over the usefulness and safety of fluoride, does adding fluoride to water really seem like good medicine?

Whether or not your water supply is fluoridated depends on where you live. In the UK, Ireland is the most heavily country: About three-quarters of its water supply is treated with fluoride. Interestingly, while the Irish have generally good dental health, studies show lower dental disease in non-fluoridated areas. Wales and Scotland are non-fluoridated. In England, fluoridation depends very much on location. A full list of fluoridated areas can be obtained by logging on to

Certain steps can be taken to reduce exposure to fluoride. Those living in a fluoridated region may avoid tap water to drink, or filter their water. Jug and plumbed-in carbon filters can be quite effective in reducing the fluoride content of water. For those wanting to avoid fluoride in toothpaste, many natural alternatives exist. One particular brand based on aloe vera (called AloeDent) comes in several forms, one of which contains vitamin K. Vitamin K has been shown to be effective in preventing tooth decay. AloeDent can be found in health food stores.

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