Fluoride chemicals added to public water supplies, boosts lead absorption in lab animals' bones, teeth and blood, report Sawan, et al. (Toxicology 2/2010). Earlier studies already show children's blood-lead-levels are higher in fluoridated communities, reports Sawan's research team.
"…exposure to increased amounts of lead and fluoride occurs at about the same age (1-3 years)… Therefore, this is a critical time when systemic exposure to fluoride should be minimized since fluoride may increase lead accumulation," the researchers caution.
Low-level lead exposure is associated with lower IQ, ADHD and many health and behavior ailments.
Fluosilicic acid (fluoride) is added to water supplies ostensibly to reduce tooth decay.
Sawan's team put fluosilicic acid, with and without lead, into lab animals' drinking water. They found more lead in tooth enamel, surface bone, whole bone, and tooth dentine in rats co-exposed to fluoride and lead.
Possibly anticipating criticism that rats were fed higher fluoride-concentrated water than people drink, the authors write, "This concentration was chosen because it produces plasma fluoride levels that are comparable with those commonly found in humans…"
Increased prevalence and severity of fluoride-discolored teeth (fluorosis) proves U.S. children are already fluoride-overexposed, "which may cause their blood-lead levels to increase and produce more lead toxicity," they write.
"These findings suggest that a biological effect, not recognized so far, may underlie the epidemiological association between increased blood-lead levels in children and water fluoridation," concludes Sawan's research team.
"[O]ur findings may have serious implications for populations exposed to increased amounts of both lead and fluoride, particularly young children," the research team writes.
Fluoridation chemicals often contain lead (NSF International).