“Approximately 80% of an absorbed dose of fluoride is retained in young children compared to 50% in adults. This is supported by the finding that renal fluoride excretion rate is lower in children than adults. This difference in fluoride retention is due to high fluoride uptake in developing bones.”
SOURCE: Agency for Toxic Substances & Disease Registry (ATSDR) (2003). Toxicological profile for fluorides, hydrogen fluoride, and fluorine. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
“Overall, an average of 86.8% of the dose was retained by the infants, which is about 50% higher than would be expected for adults… There is a clear need for more information about the renal handling and general metabolism of fluoride in young children…”
SOURCE: Whitford GM. (1994). Intake and metabolism of fluoride. Advances in Dental Research 8:5-14.
“Our finding that mean retention of fluoride [among infants] was 83.4% of the quantity of fluoride absorbed from the dose of supplement may be compared with the finding in adults that mean extrarenal clearance of fluoride from a dose of supplement given to adults was 55.3%.”
SOURCE: Ekstrand J, et al. (1994). Fluoride pharmacokinetics in infancy. Pediatric Res. 35:157-63.
“The breast-fed infants were in a negative F balance, excreting more F than they ingested. The bottle-fed infants, on the other hand, retained more than 50% of the ingested F dose. The rapidly growing skeleton certainly enhances F retention, but a contributing factor might also be a slow elimination rate for F, caused by a not fully developed renal handling capacity for F at this early stage of life.”
SOURCE: Ekstrand J, et al. (1984). Fluoride Balance Studies on Infants in a 1-ppm-Water-Fluoride Area. Caries Res. 18:87-92.