In debates surrounding water fluoridation, proponents of the practice frequently confuse the terminology of dose and concentration. Opponents rightly point out this elementary confusion (Connett 2010). Regardless, the error continues to be widely perpetuated without retraction. To clarify:
"Dose is the total amount of a substance administered to, taken, or absorbed by an organism; whilst concentration is the quantity of a material or substance contained in unit quantity of a given medium or system" (Duffus 2001).
In the context of water fluoridation, therefore, concentration is the amount of fluoride (mg/L) present in drinking water; whilst dose is the amount consumed by human beings drinking that water. So, what is all the fuss about?
The objections to water fluoridation, when the difference between dose and concentration is properly understood, seem self-evidently justified. Think about it. Once fluoridation chemicals are added to drinking water by water departments, with the stated purpose of treating the human being, there is obviously no way to control how much water people drink and therefore no way to monitor the dose absorbed by the organism.
And if you can't monitor or control the dose, how can you monitor the potential effects? When a physician treats an individual, that individual is specifically monitored. When people drink fluoridated water from public water supplies, the only thing being 'controlled' is the concentration in the water and most certainly not the dose.
The plot thickens when we consider that fluoridated drinking water is not the only source of fluoride via which 'the organism' is exposed. There are many other sources of fluoride that combine to increase peoples' total dose (NRC 2006; FAN 2015). Significantly, though, it must be remembered that:
"The major dietary source of fluoride for most people in the United States is fluoridated municipal (community) drinking water, including water consumed directly, food and beverages prepared at home or in restaurants from municipal drinking water, and commercial beverages and processed foods originating from fluoridated municipalities" (NRC 2006, p. 24).
In other words, there is no doubt that artificial fluoridation programs are the main contributor of increased doses of systemic fluoride throughout the population. Why is this fact so important? Well, it should be blindingly obvious. Because:
"A number of researchers have pointed out both the importance of evaluating individual fluoride intake from all sources and the difficulties associated with doing so, given the variability of fluoride content in various foods and beverages and the variability of individual intakes of the specific items... However... for typical individuals, the single most important contributor to fluoride exposures (approaching 50% or more) is fluoridated water and other beverages and foods prepared or manufactured with fluoridated water" (NRC 2006, p. 87).
Still not obvious? Well, consider the fact that biomonitoring of the population is grossly inadequate (NRC 2006, p. 87). In other words, people are consuming uncontrolled amounts of fluoride across the entire population, and no one is properly monitoring them for potential negative individual effects.
Therefore, focusing on the concentration of fluoride in drinking water alone is grossly inadequate. The dose is what counts. And the dose is 'the big unknown' due to the uncontrolled method of delivery (Connett 2011). The logical extension of the issue spills into the arena of 'Margin of Safety', which is another whole discussion (Connett 2011).
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