Prenatal fluoride exposure and child IQ: Is tea a key source of fluoride?

Tea consumption can substantially contribute to fluoride intake. We examined the association between child intelligence and prenatal fluoride exposure from mother's tea consumption.

Participants included 485 mother-child pairs from the Maternal-Infant Research on Environmental Chemicals cohort. Maternal consumption of tea, coffee, and water during pregnancy was assessed via self-report. We estimated fluoride intake from tea (mg/day) by combining fluoride content from tea with each 200 mL cup of tap water. We assessed child full-scale IQ (FSIQ) at 3 to 4 years of age. We used multiple linear regression models to examine associations between maternal fluoride intake (from tea and from all beverages) and child FSIQ, adjusting for relevant covariates.

Most participants (61%) reported consuming either green or black tea during pregnancy, with daily consumption reported by 2.3% and 8.4%, respectively. Women who consumed tea during pregnancy had higher mean total fluoride intake levels (0.76 mg/day) than those who did not (0.41 mg/day). Each 0.5 mg/day increase in fluoride intake was associated with a 2.24-point decrease in FSIQ (95%CI: -3.93,-0.55) when estimated from tea alone and a 1.67-point decrease (95%CI: -3.10,-0.24) when estimated from all beverages combined. The association between total fluoride intake and child IQ did not differ between tea consumers and non-tea consumers (p-interaction = 0.58).

Maternal fluoride exposure from tea consumption is associated with reduced child FSIQ independent of other beverages. As tea can be a major source of exposure, pregnant women may consider limiting intake. Clearer labeling of fluoride content could support informed choices.