When kids have just enough iodine in their urine but are exposed to more fluoride, their bodies might make less of an important thyroid hormone called TT3 — like their thyroid is struggling a bit under those conditions.

47

Pro

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Against

Evidence from Studies

Supporting (1)

47

Community contributions welcome

47

Iodine Modifies the Susceptibility of Thyroid to Fluoride Exposure in School-age Children: a Cross-sectional Study in Yellow River Basin, Henan, China

Cross-Sectional Study

Human

2021 Oct

This study found that when kids have a normal amount of iodine in their urine, too much fluoride makes their thyroid produce less of an important hormone called TT3. So yes, fluoride can mess with thyroid function—but only when iodine isn’t too high or too low.

Contradicting (0)

0

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No contradicting evidence found

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

Source Study

Iodine Modifies the Susceptibility of Thyroid to Fluoride Exposure in School-age Children: a Cross-sectional Study in Yellow River Basin, Henan, China

Score: 47

DOI: 10.1007/s12011-020-02519-8

Similar Assertions

When kids have more iodine in their urine, fluoride doesn’t seem to make their thyroid gland grow as much—so iodine might help protect their thyroid from fluoride’s effects.

47

0

90%

In kids, more fluoride in their urine seems to be linked to bigger thyroids, but iodine in their urine doesn’t seem to make a clear difference—so fluoride might be the main thing affecting their thyroid size.

47

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In kids aged 7 to 12, the more fluoride they have in their urine, the bigger their thyroid gland tends to be — by a tiny amount, about the size of a small grape.

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People who drink water with a lot of fluoride for a long time may have lower levels of certain thyroid hormones and higher levels of a hormone that tells the thyroid to work harder—this could mean their thyroid isn’t working quite right.

1

0

77%

Fluoride might stop your thyroid from absorbing enough iodine, which it needs to make hormones—this could make an iodine shortage worse and mess up your metabolism.

1

0

77%