A new study from Canada published this week in the journal Nutrients, found that pregnant women who had low iodine levels and elevated fluoride had boys who suffered an average IQ loss that was 58% greater than the already significant IQ loss from elevated fluoride alone [Goodman 2022]. Artificially fluoridated drinking water was the main source of the fluoride. The boys of women with low iodine levels lost, on average, 9.3 IQ points, while those of mothers with adequate iodine lost 5.9 IQ points, for every 1 mg/g increase in mother’s urine fluoride concentration.* In previous work in the same group of pregnant mothers, drinking water fluoridated at 0.7 mg/L was associated with an increase of roughly 1 mg/g in urine fluoride [Till 2018].
23% of the Canadian women who took part in the new study were classified as having “low iodine”. The iodine status of pregnant women in the USA is much worse than in Canada, with well over 50% currently meeting the criteria for “low iodine” used in this study [Watson 2020].
The authors point out that theirs was the first mother-child cohort study “to estimate the interplay between prenatal fluoride exposure and maternal iodine status in relation to child IQ”. They also warned that “even mildly reduced iodine levels may have biological significance when interacting with fluoride.”
https://fluoridealert.org/content/new-study-low-iodine-in-pregnancy-worsens-iq-loss-from-fluoride/