Fluoride Action Network

The Minimum Dose that Produces Acute Fluoride Toxicity

F.A.N. | April 2012 | By Michael Connett

A chemical’s toxicity can be measured in two basic ways: (1) chronic toxicity and (2) acute toxicity. Chronic toxicity refers to the dose of a chemical that, while safe if ingested once, can cause harm if ingested over a long period of time. Acute toxicity, by contrast, refers to the dose of a chemical that, if ingested in one sitting, can cause immediate harm (i.e., poisoning).

In the case of fluoride, early symptoms of acute fluoride poisoning include gastric pain, nausea, vomiting, and headaches. Studies have found that these symptoms are produced by a single ingestion of just 0.1 to 0.3 mg/kg (i.e., 0.1 to 0.3 milligrams of fluoride for every kilogram of bodyweight). A child weighing 10 kilograms, therefore, can suffer symptoms of acute toxicity by ingesting just 1 to 3 milligrams of fluoride in a single sitting. As demonstrated here, 1 to 3 mgs of fluoride is found in just 1 to 3 grams of toothpaste (less than 3% of the tube) — including toothpaste that is marketed specifically to children with bubble-gum and fruit flavors. Children, as well as adults, can also ingest acutely toxic doses of fluoride from fluoride gels, food fumigated with sulfuryl fluoride, and tap water following an accident in the fluoridation equipment.

STUDIES:  Minimum dose of fluoride that causes acute toxicity:

“[A]cute fluoride poisonings have occurred at doses of 0.1 to 0.8 mgF/kg of body weight in the USA… At least seven events of acute fluoride poisoning that are related to the fluoridation of drinking water have formally been reported in the USA… Among these occurrences, the estimated toxic dose was lowest in the 1978 event in New Mexico, which involved children in kindergarten and nursery school with the total amount of fluoride per child of 1.4 to 90 mg, which is calculated to be approximately 0.1 mg F/kg in subjects with a body weight of 15 kg. The estimated minimum toxic doses of fluoride involved 0.21, 0.3, 0.34, 0.5, and 0.8 mg/kg in the other events of acute fluoride poisoning in the list, which are much lower than those reported before… Thienes et al in 1972 reported that the dose of fluoride which induces nausea is 0.12 mg/kg (7.2 mg of fluorine/60 kg of body weight), which is close to the toxic doses estimated in the events of fluoride poisoning in the USA… Kasahara et al estimated the minimum toxic dose of fluoride at about 0.2 mgF/kg. They reported that 60 persons took 10 mg amounts of fluoride and more than 90% of them had symptoms. Asou selected 0.1 mg F/kg as the minimum toxic dose.”
SOURCE: Akiniwa, K. (1997). Re-examination of acute toxicity of fluoride. Fluoride 30: 89-104. [See study]

“The lowest estimated dose of fluoride that caused symptoms was 0.3 mg per kilogram; 16 percent of the case patients received an estimated dose of less than 1.0 mg per kilogram. The lowest level at which an effect was observed — a level of less than 1 mg of fluoride per kilogram — is similar to that reported in some studies…”
SOURCE: Gessner BD, et al. (1994). Acute fluoride poisoning from a public water system. New England Journal of Medicine 330:95-9.

Studies: Early Symptoms of Acute Fluoride Toxicity:

“Ingested fluoride is transformed in the stomach to hydrofluoric acid, which has a corrosive effect on the epithelial lining of the gastrointestinal tract. Thirst, abdominal pain, vomiting, and diarrhea are usual symptoms. Hemorrhage in the gastric mucosa, ulceration, erosions, and edema are common signs.”
SOURCE: Environmental Protection Agency. (1999). Recognition and Management of Pesticide Poisonings. 5th Edition.

“The most common symptoms were nausea (97%), vomiting (68%), diarrhea (65%), and abdominal cramps (53%); 14 people (41%) reported headaches, four (12%) reported burning sensations in the throat or chest, and one person reported excessive salivation.”
SOURCE: Penman AD, Brackin BT, Embrey R. (1997). Outbreak of acute fluoride poisoning caused by a fluoride overfeed, Mississippi, 1993. Public Health Reports 112:403-9.

“Nausea (90%), vomiting (80%), abdominal pain (52%), diarrhea (23%), loss of appetite (13%), headache (11%), weakness (10%), itching (9%), numbness or tingling of an extremity (4%), shortness of breath (4%), fatigue (4%).”
SOURCE: Gessner BD, et al. (1994). Acute fluoride poisoning from a public water system. New England Journal of Medicine 330:95-9.

“symptoms included: abdominal cramping (66 per cent), nausea (62 per cent), headache (49 per cent), diarrhea (42 per cent), vomiting (13 per cent), diaphoresis (profuse sweating) (12 per cent), and fever (4 per cent).”
SOURCE: Petersen LR, et al. (1988). Community health effects of a municipal water supply hyperfluoridation accident. American Journal of Public Health 78: 711-3.