Fluoride is a mineral that is naturally present in varying amounts in groundwater throughout the country. In the 1940s, researchers observed that those areas with the highest amount of natural fluoride in the water had significantly lower rates of dental caries. Scientists found that adding fluoride to water a level of 1 mg per liter (which has since been reduced to 0.7 mg/L) was optimal for preventing tooth decay, and public water systems throughout the US began adding fluoride to the water supply. Today, approximately 72 percent of the population lives in areas where the water is fluoridated. However, significant controversy has sprung up in recent decades over whether the benefits outweigh the risks of this practice.
There seems to be no question that a certain amount of fluoride helps to protect our teeth. Fluoride has been shown to reduce dental cavities by 18%-40%. However, fluoride is not without its dangers. And since the mineral also shows up in places other than the drinking water supply, there is some evidence that some people may be getting too much of it. 
A large number of other items (in food and elsewhere) already contain fluoride in varying levels. For instance, a 12-oz. Coke contains .353 mg of fluoride, a head of iceberg lettuce can contain 1.8 mg of fluoride and black tea can contains a whopping 9 mg/L of fluoride! One of the reasons for this is the fact that conventional farming commonly uses pesticides containing sodium aluminum fluoride. This is a very sticky pesticide that resists washing unless you are using a rather strong scrub brush. In addition, much of the water used in agriculture has been fluoridated. Add to this the amount of fluoride contained in toothpaste and mouthwash and you can receive significantly more than the optimal recommended amount of fluoride for the day.
Numerous studies have shown that there is no association between fluoride and cancer when fluoride is taken in small amounts. However, larger amounts of fluoride can lead to skeletal fluorosis, a condition causing damage and pain in bones and joints. Excessive fluoride has been shown to increase bone fractures, particularly hip fractures in older women, according to a study published in the Journal of the American Medical Association. Other research suggest a link between larger amounts of fluoride and an increase in the incidence of dental fluorosis in children (cosmetic pitting of the tooth enamel).
Considering how much fluoride we might take in on any given day, it may seem unnecessary to fluoridate the water supply. And as opponents of the practice point out, there is no way of controlling exactly how much fluoride each person actually takes in each day. Those who drink greater amounts of water get far more than those who don’t, and children are likely to get far more fluoride in relation to their weight than adults. There is also the issue of essentially force-medicating an entire population. Most countries in continental Europe have banned the practice of water fluoridation due to the combination of unsettled science and moral ambiguity, even some who had tried it for some years.
If you are concerned that you may be getting too much fluoride in your water, you can opt for water that is either distilled or processed by reverse osmosis. Conventional home water filters such as the Brita or Pur will not remove fluoride. Most bottled water is also fluoridated, so be sure to read the label to ensure it is either distilled or has received reverse osmosis.
