The 2006 US National Research Council report Fluoride in Drinking Water: A Scientific Review of EPA’s Standards, though far from perfect, is the most comprehensive review of fluoride toxicity conducted so far. In the chapter on musculoskeletal effects it says “A previous NRC report (NRC 1977) stated that a retention of 2 mg of fluoride per day (corresponding approximately to a daily intake of 4-5 mg) ‘would mean that an average individual would experience skeletal fluorosis after 40 yr, based on an accumulation of 10,000 ppm fluoride in bone ash.'” (NRC 2006, 143) I thought I’d do a calculation to check that claim of 10,000 ppm accumulated fluoride in bone ash, which is enough to cause the crippling, third stage of skeletal fluorosis in many people.
A retention of 2 mg of fluoride per day for 40 years gives
0.002(40)(365.25) = 29.22 grams
, which happens to be several times higher than what is required to kill an average adult if taken in a single dose. Bone ash weight is a measure of bone mineral content, and according to the US Centers for Disease Control and Prevention the average total age-adjusted body bone mineral content for males 20 years and over is 2720.04 g, measured by dual energy x-ray absorptiometry (DXA) (Looker et al 2013, 9). That gives a fluoride concentration of
29.22(1,000,000)/2720.04 = 10,742.5 ppm or 11,000 ppm to 2 significant figures.
The corresponding calculation for women is
29.22(1,000,000)/2108.32 = 13,859.4 ppm or 14,000 ppm.
On the face of it, the 1977 NRC calculation was an underestimate. However, the pathological increase in bone mass which can accompany skeletal fluorosis has not been taken into account here. It could be also be argued that measurement by DXA is not an adequate substitute for measurement of bone ash weight, though, so let’s look at it from a different angle. The average dry, defatted skeleton weight for young adult males has been estimated at 4.0 kg (Heymsfield et al 2005, 291). Throwing the racist fluoridationists a bone, the average percentage total skeleton ash weight for white adult males aged 30 to 85 years has been estimated as 66.4% (Trotter and Hixon 1974, 13-14).
percentage ash weight = (weight of ash)(100)/weight of dry, fat-free bone
so fluoride concentration in bone ash = 29.22(1,000,000)/(4.0)(1000)(0.664) = 11,001.5 (i.e. 11,000) ppm
Again, the corresponding figure for women will be considerably higher.
The data upon which these calculations are based are not perfect, a daily fluoride retention of 2 mg is probably somewhat higher than average, and around 99% of retained fluoride is found in bone, not 100%. Nevertheless, this preliminary investigation strongly suggests that being force-fluoridated for a lifetime is very far from safe. “On the basis of data on fluoride in the iliac crest or pelvis, fluoride concentrations of 4,300 to 9,200 mg/kg in bone ash have been reported in cases of stage II fluorosis, and concentrations of 4,200 to 12,700 mg/kg in bone ash have been reported in cases of stage III fluorosis. The overall ranges for other bones are similar.” (NRC 2006, 143) From what I’ve read, some common early signs of skeletal fluorosis are gastrointestinal issues (Susheela et al 2014, 576), neck stiffness, and knee osteoarthritis (Savas et al 2001).
Looker AC, Borrud LG, Hughes JP, Sherman M (2013). Total body bone area, bone mineral content, and bone mineral density for individuals aged 8 years and over: United States, 1999-2006. National Center for Health Statistics. Vital and Health Statistics 11(253): 1-78.
NRC (National Research Council) (2006). Fluoride in drinking water: a scientific review of EPA’s standards. Washington DC (USA): National Academies Press 530 p.
Savas S, Cetin M, Akdogan M, Heybeli N (2001). Endemic fluorosis in Turkish patients: relationship with knee osteoarthritis. Rheumatology International 21(1): 30-35.
Susheela AK, Mondal NK, Tripathi N, Gupta R (2014). Early diagnosis and complete recovery from fluorosis through practice of interventions. Journal of the Association of Physicians of India 62: 572-579.
Trotter M, Hixon BB (1974). Sequential changes in weight, density, and percentage ash weight of human skeletons from an early fetal period through old age. The Anatomical Record 179(1): 1-18.