Lethal heart failure has also been reported in several children soon after swallowing fluoride from concentrated dental gel treatments. The mechanism by which fluoride causes heart block appears to be due to preventing calcium from normally entering heart cells to couple electrical excitation to mechanical contraction of the heart. In spite of the vast expenditure of funds and equipment to help ensure that fluoridation overfeeds do not cause acute poisoning, overfeeds yet have continued to occasionally occur. In kidney dialysis wards even lower level overfeeds have caused acute lethality.
Fluoridated water at targeted levels without an overfeed causes increased morbidity in kidney dialysis patients being chronically dialyzed with the treated water. Here the fluoride blood level approximately equals that in the water The FDA ruled that fluoridated water cannot be used in kidney dialysis. Indeed, in research mammals a blood level of approximately 1 ppm causes swelling of heart muscle cells and degradation of myocardial contractile filaments.
1 ppm fluoridated water consumption leads typically to ~0.15 ppm blood fluoride. Typically, 75-90% of the fluoride ingested daily from fluoridated water or other dietary sources is assimilated from the gastrointestinal tract. 50% of the assimilated fluoride is retained in calcium-rich tissue especially bone, and the remaining 50% is eliminated in the urine. About 60% of the fluoride in the bloodstream at any time in a fluoridated U.S. water area comes from water consumption, and about 15% is from toothpaste use. The blood fluoride also distributes between that bound to protein and the free ion [70] which diffuses through plasma and into red blood cells.
Systemic fluoride at sub-acute levels incorporates into atherosclerotic plaque in coronary vessels of cardiovascular disease patients directly revealed with positron emission tomography scans in a study at the Veterans Administration Healthcare Center, Los Angeles. Patients with dental fluorosis were found to have significantly prolonged left atrial relaxation times, and increases in heart disease mortality after fluoridation is begun have been reported in several examined cities.
Epidemiologic studies in Ireland have recently revealed compelling evidence that the fluoridation of a population is associated with an increased incidence of an array of disease states including various cancers, heart disease mortality, and sudden infant death syndrome, all which are increased in incidence in the artificially fluoridated Republic of Ireland compared to non-fluoridated Northern Ireland. The systemic effects that are possible from the continuous consumption of fluoridated water are diverse. Hypothyroidism incidence is increased in regions in the U.K. that are fluoridated compared to non-fluoridated.
A close relationship between fluoridation status and the incidence of attention deficit hyperactivity disorder ADHD has been found. A close correlation of blood fluoride with decreasing IQ has been reported in dozens of published studies. Artificially fluoridated water supplies are documented to have caused horses, frogs, chinchillas, and alligators to die prematurely that consume treated water continuously for extended periods of time. Discharged fluoride into the Columbia River to ~0.3 ppm blocked salmon navigation upstream to spawn.
The incidence of racehorse breakdowns causing animals to be euthanized closely follows the fluoride concentration in the treated water supply in both thoroughbreds and quarterhorses. Since 90% of racehorses have stomach ulcers it is postulated that the HF aggravates GI pain which may cause missteps with bone breaks.