The kidneys are the organ responsible for clearing fluoride from the body. In the process of doing so, the kidneys are exposed to concentrations of fluoride that exceed, by a factor of 50, the concentration of fluoride in human blood. As such, the kidney have long been considered a potential target organ for fluoride toxicity.
Excerpts from the Scientific Literature:
“Human kidneys… concentrate fluoride as much as 50-fold from plasma to urine. Portions of the renal system may therefore be at higher risk of fluoride toxicity than most soft tissues.”
SOURCE: National Research Council. (2006). Fluoride in Drinking Water: A Scientific Review of EPA’s Standards. National Academies Press, Washington D.C. p236.
“Most of the removal of fluoride that occurs from the body (approximately 50% of daily intake) is done by renal excretion. The kidney cells are therefore a possible target of fluoride toxicity because they can be exposed to high concentrations of fluoride.”
SOURCE: Collins TFX, Sprando RL. (2005). Fluoride–toxic and pathologic effects: Review of current literature on some aspects of fluoride toxicity. Reviews in Food and Nutrition Toxicity. 105-41.
“Based on these studies it is known that, among soft tissues, the kidney has the highest fluoride concentrations. This is mainly attributable to high concentrations within the tubular and interstitial fluids in the medullary papillary regions.”
SOURCE: Whitford G. (1996). The Metabolism and Toxicity of Fluoride. 2nd Revised Edition. Karger: Basel. p 30.
(NOTE: Since the publication of this report, it has been discovered that the soft tissue of the pineal gland contains higher fluoride levels than the kidney.)
“Effects in the kidneys are of the first to be seen in fluoride exposure of mammals. The reason for this is considered to be the relative high concentrations of fluoride found in the kidneys and in the urine during exposure.”
SOURCE: Hongslo CF, Hongslo JK, Holland RI. (1980). Fluoride sensitivity of cells from different organs. Acta Pharmacologica et Toxicologica 46:73-77.