The question below was posted today on the website of the Alberta Health Services (AHS). The website invites questions about fluoridation, so that people may separate "fact from fiction". Calgary will vote on fluoridation on Oct. 18, 2021.
- SEE: AHS website - Fact or Fiction
https://together4health.albertahealthse ... tool=qanda
A response from Alberta Health Services was received on October 7, 2021. Unfortunately, the AHS did not address our concerns about TSH levels during pregnancy. We have posted the AHS response below the letter, as well as our reply to it. Please follow the thread.
- PFPC letter - Sept. 27, 2021. viewtopic.php?f=91&t=3693
AHS Response - Oct. 7, 2021. viewtopic.php?p=4418#p4418
PFPC Response to AHS - Oct. 8, 2021. viewtopic.php?p=4419#p4419
You state that it is safe to drink fluoridated water in pregnancy, referring to the recent IQ studies.
What about fluoride effects on TSH, the thyroid-stimulating-hormone?
Fluoride raises TSH levels even at water concentrations used for community water fluoridation (1). The actual evidence reviewed in the 2019 CADTH report shows this quite clearly (2).
Out of the 5 CADTH-reviewed papers that reported TSH values, 3 reported an increase of TSH levels with increasing fluoride intake (see Kheradpisheh et al., 2018; Xiang et al., 2009; Singh et al., 2014). A fourth (Khandare, 2017) was done at high altitude where TSH/TH metabolism is vastly different, and the 5th by Alberta's McLaren and Barberio used an outdated reference range upper limit of 4.8 mIU/L, almost twice as high as the 2.5 mIU/L upper limit for the first trimester. It is incomprehensible how that study on thyroid and IQ failed to consider TSH limits during pregnancy (3).
WHY IS THIS IMPORTANT?
The cut-off upper limit for TSH in the first trimester is 2.5 mU/L, as advised by most international health organizations, including the Alberta Medical Association (4). This limit is set because TSH levels above 2.5 mU/L are associated with a decrease in cognitive function in offspring (5,6), as well as adverse pregnancy outcomes such as miscarriage, pre-term birth, and low birth weight (6). There are now hundreds of studies documenting adverse health outcomes correlating with increasing TSH levels above 2.5 mIU/L - but still within the normal range, including cardiovascular disease, metabolic syndrome (MetS), Non-Alcoholic Fatty-Liver-Disease (NAFLD), thyroid cancer, and diabetes (7).
The weight of the available scientific evidence appears to show that not only is fluoridated water unsafe for pregnant women but steps should be undertaken to reduce all high sources of fluoride during pregnancy, such as tea, grape products, oral care products, etc...
Why is the TSH issue not addressed?
Thank you for your answer.
1) Kheradpisheh Z, Mirzaei M, Mahvi AH, Mokhtari M, Azizi R, Fallahzadeh H, Ehrampoush MH - "Impact of Drinking Water Fluoride on Human Thyroid Hormones: A Case-Control Study" Scientific Reports Volume 8:2674 (2018)
At fluoride water concentrations from 0.3 to 0.5 ppm, TSH was increased by 0.5 mIU/L, compared to the area with 0 to 0.3 ppm. In this study, fluoride resulted in a TSH increase from 2.2 mIU/L to 2.7 mIU/L. (2.7 mIU/L is above the recommended upper limit of TSH for the first trimester of pregnancy.)
"It was found that fluoride has impacts on TSH, T3 hormones even in the standard concentration of less than 0.5 mg/L."
2) CADTH TECHNOLOGY REVIEW Community Water Fluoridation Programs: A Health Technology Assessment — Review of Dental Caries and Other Health Outcomes (2019)
https://www.cadth.ca/sites/default/file ... report.pdf
3) PFPC - Comments on the study by Barberio et al. (2020)
4) TOP Alberta - Clinical Practice Gudielines - Thyroid (2014)
https://actt.albertadoctors.org/CPGs/Li ... deline.pdf
5) Wang M, Liu L, Li H, Li Y, Liu H, Hou C, Zeng Q, Li P, Zhao Q, Dong L, Zhou G, Yu X, Liu L, Guan Q, Zhang S, Wang A - "Thyroid function, intelligence, and low-moderate fluoride exposure among Chinese school-age children" Environ Int 134:105229 (2020)
"We detected a significant modification effect by TSH on the association between urinary fluoride and IQ scores, without mediation by THs."
6) Lee SY, Pearce EN - "Testing, Monitoring, and Treatment of Thyroid Dysfunction in Pregnancy" J Clin Endocrinol Metab 106(3):883-892 (2021)
https://academic.oup.com/jcem/article-a ... m=fulltext
7) PFPC - 70 studies on adverse effects: TSH within the normal range (2021)