In August 2013, the European Food and Safety Authority proposed an adequate intake (AI) level for fluoride. Essentially, they just copied the AI set by the U.S. Institute of Medicine in 1997 – the numbers are identical. For most children and adults, the adequate amount was set at .05 milligrams per kilogram of body weight per day. According to current dental science, fluoride works topically to prevent tooth decay. For adults, fluoride works only while it is in the mouth, before it is swallowed. Thus, a person who ingests the recommended amount will get no more benefit than a person who swallows significantly less fluoride but gets the same topical exposure.
For example, “Joe” drinks fluoridated water 8 times a day and receives the recommended AI. “Bill” puts some fluoridated water in his mouth 8 times a day, swishes it around and spits it out. Both would get the same benefit, but “Bill” will probably not be ingesting the AI amount.
EFSA wrote: “Epidemiological studies have shown an inverse correlation between the presence of fluoride in drinking water and the prevalence of dental caries in children.” This is where the faulty assumption comes in. What matters is not how much fluoride you swallow, but how often your teeth get an effective topical exposure to fluoride. Yes, many people in a fluoridated area will ingest the recommended AI, but that is not why they have less tooth decay than people in non-fluoridated areas.
The idea of an AI for fluoride is left over from decades ago, when fluoride was thought to work only for children who swallowed it and thus had it incorporated into their developing teeth. That’s another idea about fluoride’s benefit that is dying a slow death in scientific circles.
The idea of an “adequate intake” also helps to promote and justify fluoridation, as a target population might not be ingesting the AI amount unless fluoridation is introduced. This was the case with the 1997 Institute of Medicine “Dietary References” report, which falsely tried to sell the idea that their AI was the same as the recommended intake levels during the prior 47 years. Americans had far less fluoride exposure decades ago, and adults drinking fluoridated water back then did not ingest .05 milligram per kilogram of body weight per day. They did ingest that amount by 1997, as average fluoride intake had increased significantly since 1945. The average amount ingested by fluoridated populations in 1997 conveniently happened to be the same as the AI set by the Institute of Medicine. But, decades ago, the optimum intake amount was roughly half of that.
In non-fluoridated areas, adults typically ingest less than the AI amount. If public health officials thought that ingesting the AI amount was important, they would be recommending fluoride supplements for adults in those areas. But that has never happened. There is no convincing evidence that fluoride supplements are effective for adults or older children.
For the purposes of this article, the author has adopted the current fluoride ideology from large government agencies and scientific institutions that support fluoridation. He may not agree with everything in that ideology.
Sources for this article include:
2013 EFSA news story announcing their AI for fluoride:
1997 Institute of Medicine Dietary Reference Intakes document:
Darlene Sherell lists references that show lower recommended levels in past decades
About the author:
Doug Cragoe is an activist concerned with the increasing level of fluoride exposure in the United States.