New research suggests that the intrauterine period is the time when the
developing brain is most at risk for fluoride ion (F)-induced neurotoxicity. The
prevention of F-induced neurotoxicity and IQ loss in children must therefore start in pregnancy and continue during childhood, especially early childhood up to the age of 7 yr. A safe daily intake of F for pregnant women and children of all ages to give protection from F-induced neurotoxicity can been estimated to be approximately 0.04 mg F/day (0.0006 mg F/kg bw/day for a 70 kg woman) and 0.15 mg F/day (0.003 mg F/kg bw/day for a 45 kg child, the 90th percentile children’s body mass at 8–13 yr), respectively. The quantities of water, fluoridated with 0.7 mg F/L (0.7 ppm) which contain 0.04 and 0.15 mg of F are 72 and 214 mL, respectively, approximately a third of a cupful and a cupful (1 cup = 8 oz = 237 mL). With this being less than 30% of the mean daily water intake for persons aged <0.5–6, 7–19, and ?20 yr, in order to prevent F-induced IQ loss in children, pregnant women and children, up to the age of 7 yr, should avoid the use of fluoridated community water supplies and other dietary sources high in F including tea and fluoridated dental products that may be swallowed such as fluoridated toothpaste and professionally applied fluoride gels and varnishes. Using the safe dose of F for preventing in utero foetal neurotoxicity, derived with the LOAEL/NOAEL method, of 0.04mg F/day, and taking the body weight of a pregnant adult woman as 70 kg, the oral reference value for longer-term (up to 10% of an average life span) exposure (RfVLO) can be calculated to be approximately 0.0006 mg/kg bw/day (0.04÷70=0.00057). This level is 100 times less than the current reference dose (RfD) of 0.06 mg/kg bw/day for preventing objectionable dental fluorosis of moderate or severe severity.