Only a small margin separates supposedly beneficial fluoride levels from amounts that are known to cause adverse effects. Dr. James Patrick, a former antibiotics research scientist at the National Institutes of Health, describes the predicament:
“[There is] a very low margin of safety involved in fluoridating water. A concentration of about 1 ppm is recommended. …in several countries, severe fluorosis has been documented from water supplies containing only 2 or 3 ppm. In the development of drugs… we generally insist on a therapeutic index (margin of safety) of the order of 100; a therapeutic index of 2 or 3 is totally unacceptable, yet that is what has been proposed for public water supplies.”(56)
Other countries argue that even 1 ppm is not a safe concentration. Canadian studies, for example, imply that children under three should have no fluoride whatsoever. The Journal of the Canadian Dental Association states that “Fluoride supplements should not be recommended for children less than 3 years old.” (57) Since these supplements contain the same amount of fluoride as water does, they are basically saying that children under the age of three shouldn’t be drinking fluoridated water at all, under any circumstances. Japan has reduced the amount of fluoride in their drinking water to one-eighth of what is recommended in the U.S. Instead of 1 milligram per liter, they use less than 15 hundredths of a milligram per liter as the upper limit allowed.(58)
The 1 ppm dosage recommendation for water fluoridation has a checkered past, and its present is even more so. As we have seen, the first mention of this “magic” number was made by Dr. Trendley Dean, who jiggled his results to reach the conclusion that “fluoride levels of up to 1.0 ppm in drinking water did not cause mottled enamel; if the fluoride exceeded this level, however, fluorosis would occur.”(59)
But the adoption of this dosage for water fluoridation was not Dean’s brainchild. It was set in 1953 by Dr. Harold C. Hodge, Ph.D., then chairman of the US National Academy of Sciences committee on toxicology. Unfortunately, Dr. Hodge made a serious miscalculation in his estimate of the safe dosage level for fluoride. His figures err by a factor of 2.25, which means that they understate the toxicity of fluoride considerably. The story of this potentially fatal miscalculation is told in a document from the UK National Pure Water Association:
It is important when any new drug is marketed that the dose at which it is toxic is determined. There is then a margin allowed for safety (usually a factor of 100) and a maximum dose is published. In 1953 the National Academy of Sciences published their estimate of the quantity of fluoride which produces the condition known as crippling skeletal fluorosis. The calculation was done by a famous toxicologist, Harold C. Hodge, Ph.D., who was chairman of the US National Academy of Sciences (NAS) committee on toxicology.
To arrive at his figures, Hodge cited a classic study of the effects of fluoride among cryolite workers by a European researcher, Kaj Roholm, and published in 1937.(60) Roholm’s dosage figures were presented in milligrams of fluoride per kilogram of body weight. In his study, Roholm showed that at levels of 0.2 to 0.35mg/kg some workers developed crippling skeletal fluorosis in a very short time. The first stage of the disease appeared, in general, after 2 1�years; Stage two was reached by 4 1�years; and crippling skeletal fluorosis appeared after 11 years.
Hodge wanted to apply Roholm’s figures to a typical range of body weights in order to set a maximum intake level in milligrams per day. But Hodge was American and used to dealing in pounds rather than kilograms. By using a range of body weights from 100 to 229 pounds, he multiplied the 0.2 mg figure by 100 pounds, giving a figure of 20 mg/day; and 0.35 mg by 229 pounds yielded 80 mg/day. Thus the amounts of fluoride which would cause crippling skeletal fluorosis, he said, were 20mg to 80mg per day. And rather than quote Roholm’s eleven year figure for crippling fluorosis, he gave a range of 10 to 20 years. These are the figures that appear in the American Dental Association’s pamphlet, Fluoridation Facts, and on which many other articles are based, even today.
But Hodge made a simple but significant error. Roholm’s figures were not for pounds. They were milligram per kilogram figures. Unfortunately, Hodge was the expert and no-one, apparently, checked his figures. This error, which gave a false safety margin more than double what it should have been went unnoticed for many years until anti-fluoride campaigner, Darlene Sherrell tried to duplicate Hodge’s arithmetic and couldn’t make it add up. She worked out that Hodge had made an error when he neglected to convert pounds to kilograms.
Correcting for this error, Sherrell reduced the amount of fluoride needed to be crippling to 10 to 25 milligrams per day, for 10 to 20 years.
But fluorides accumulate throughout our lives so a higher intake will have the same effect in a shorter time, and smaller doses will have the same effect in a longer time. If we apply Roholm’s dosage figures to a lifetime of 55 to 96 years, just 1 mg per day (the amount in one litre of water) for each 55 pounds of body weight could be a crippling dosage.