Systematic review of epidemiological and toxicological evidence on health effects of fluoride in drinking water

Taher, Mohamed Kadry; Momoli, Franco; Go, Jennifer; Hagiwara, Shintaro; Ramoju, Siva; Hu, Xuefeng; Jensen, Natalie; Terrell, Rowan; Hemmerich, Alex; Krewski, Daniel

doi:10.1080/10408444.2023.2295338

Cited by 17 publications

(4 citation statements)

References 100 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This brings us back to the present systematic review, by Taher et al 5 . In terms of the methods, the scope of the review is extensive.…”

Section: Commentarymentioning

confidence: 53%

“…The human evidence included in the Taher review overlaps with the draft NTP review 4 , and other systematic reviews on the neurological and health effects of fluoride in water, including a recent Irish government review (Lambe et al 6 ), and a Canadian government review (CADTH) 7 . There appear to be differing perspectives on the quality of this evidence from reviewers with a toxicology perspective (Taher et al 5 and the draft NTP review), versus those with an evidence-based medicine perspective 6 , 7 . The latter have stated that the current evidence base related to IQ is insufficient to draw conclusions, and that further high quality research is needed (Lambe et al and CADTH) 6 , 7 .…”

Section: Commentarymentioning

confidence: 99%

See 1 more Smart Citation

Fluoride and children’s IQ: evidence of causation lacking

Moore,

Glenny

2024

Evid Based Dent

View full text Add to dashboard Cite

Data sources Human, animal, and in vitro studies. Extensive literature search of multiple bibliographic databases, trial registries, major grey literature sources and bibliographies of identified studies. Study selection The authors aimed to identify studies which could be used to determine the maximum safe level for fluoride in drinking water. To identify new studies published since a 2016 Australian review, the search period was 2016 to July 2021. Studies which evaluated the association between either naturally or artificially fluoridated water (any concentration) and any health outcomes were included. No restrictions on study design or publication status. Articles published in a ‘non-Latin language’ were excluded. Screening of abstracts and full texts was in duplicate. For IQ and dental fluorosis, a top-up search was conducted between 2021 and Feb 2023. Data extraction and synthesis Extensive data extraction. Risk of bias assessment using the OHAT tool. A narrative synthesis of the results was carried out. Results The review included 89 studies in humans, 199 in animals and 10 reviews of in vitro studies. Where there was consistent evidence of a positive association, in relation to a water fluoride concentration of <20 ppm (mg F/L), and where studies were judged to be acceptable or high quality, health effects were taken forwards for further examination of causality using Bradford Hill’s 9 criteria. Of the 39 health outcomes reviewed, 4 were further assessed for causality. The authors reported ‘strong’ evidence of causality for dental fluorosis and reductions in children’s IQ scores, ‘moderate’ strength evidence for thyroid dysfunction, ‘weak’ for kidney dysfunction, and ‘limited’ evidence for sex hormone disruption. Conclusions The authors conclude that moderate dental fluorosis and reductions in children’s IQ scores are the most appropriate health outcomes to use when setting an upper safe level of fluoride in drinking water. For reductions in children’s IQ, the authors acknowledge a biological mechanism of action has not been elucidated, and the dose response curve is not clear at lower concentrations, limiting the ability to set an upper safe threshold.

show abstract

“…This brings us back to the present systematic review, by Taher et al 5 . In terms of the methods, the scope of the review is extensive.…”

Section: Commentarymentioning

confidence: 53%

Section: Commentarymentioning

confidence: 99%

Fluoride and children’s IQ: evidence of causation lacking

Moore,

Glenny

2024

Evid Based Dent

View full text Add to dashboard Cite

show abstract

“…In vitro and in vivo studies have demonstrated F − can partake in various cellular processes: transport/homeostasis, metabolism, oxidative stress, cell respiration and migration, proliferation, gene expression, signaling, apoptosis, exocytosis, endocytosis, recycling [65]. But the main mechanisms of fluoride ion toxicity are related to protein inhibition, organelle disruption, an altered pH and electrolyte imbalance [66][67][68]. Thus, the obtained gels can be applied to the surface of special sterile films and then directly to affected areas of the skin or mucous membranes.…”

Section: Toxicity Of the Gels To Siha Cellsmentioning

confidence: 99%

Fluoride-Ion-Responsive Sol–Gel Transition in an L-Cysteine/AgNO3 System: Self-Assembly Peculiarities and Anticancer Activity

Vishnevetskii,

Andrianova,

Polyakova

et al. 2024

Gels

View full text Add to dashboard Cite

Supramolecular hydrogels based on low-molecular-weight compounds are a unique class of so-called “soft” materials, formed by weak non-covalent interactions between precursors at their millimolar concentrations. Due to the variety of structures that can be formed using different low-molecular-weight gelators, they are widely used in various fields of technology and medicine. In this study, we report for the first time an unusual self-assembly process of mixing a hydrosol obtained from L-cysteine and silver nitrate (cysteine–silver sol—CSS) with sodium halides. Modern instrumental techniques such as viscosimetry, UV spectroscopy, dynamic light scattering, zeta potential measurements, SEM and EDS identified that adding fluoride anions to CSS is able to form stable hydrogels of a thixotropic nature, while Cl−, Br− and I− lead to precipitation. The self-assembly process proceeds using a narrow concentration range of F−. An increase in the fluoride anion content in the system leads to a change in the gel network morphology from elongated structures to spherical ones. This fact is reflected in a decrease in the gel viscosity and a number of gel–sol–gel transition cycles. The mechanism of F−’s interaction with hydrosol includes the condensation of anions on the positive surface of the CSS nanoparticles, their binding via electrostatic forces and the formation of a resulting gel carcass. In vitro analysis showed that the hydrogels suppressed human squamous carcinoma cells at a micromolar sample concentration. The obtained soft gels could have potential applications against cutaneous malignancy and as carriers for fluoride anion and other bioactive substance delivery.

show abstract

“…In severe cases, fluorosis can damage teeth and affect their structure [ 12 ], causing skeletal alterations [ 20 , 35 ] such as an increase in osteoporosis and bone fracture prevalence [ 36 ]. Furthermore, high fluoride exposure has also been described to reduce IQ levels in children [ 36 , 37 , 38 , 39 ].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Ilex guayusa and Piper marginatum Extract Cytotoxicity on Human Dental Pulp Mesenchymal Stem Cells

Sequeda-Castañeda,

Suárez-Carvajal,

Téllez-Corral

et al. 2024

Dentistry Journal

View full text Add to dashboard Cite

Background: Amelogenesis imperfecta is a hereditary disorder affecting dental enamel. Among its phenotypes, hypocalcified AI is characterized by mineral deficiency, leading to tissue wear and, consequently, dental sensitivity. Excessive fluoride intake (through drinking water, fluoride supplements, toothpaste, or by ingesting products such as pesticides or insecticides) can lead to a condition known as dental fluorosis, which manifests as stains and teeth discoloration affecting their structure. Our recent studies have shown that extracts from Colombian native plants, Ilex guayusa and Piper marginatum, deposit mineral ions such as phosphate and orthophosphate into the dental enamel structure; however, it is unknown whether these extracts produce toxic effects on the dental pulp. Objective: To assess cytotoxicity effects on human dental pulp stem cells (hDPSCs) exposed to extracts isolated from I. guayusa and P. marginatum and, hence, their safety for clinical use. Methods: Raman spectroscopy, fluorescence microscopy, and flow cytometry techniques were employed. For Raman spectroscopy, hDPSCs were seeded onto nanobiochips designed to provide surface-enhanced Raman spectroscopy (SERS effect), which enhances their Raman signal by several orders of magnitude. After eight days in culture, I. guayusa and P. marginatum extracts at different concentrations (10, 50, and 100 ppm) were added. Raman measurements were performed at 0, 12, and 24 h following extract application. Fluorescence microscopy was conducted using an OLIMPUS fv1000 microscope, a live–dead assay was performed using a kit employing a BD FACS Canto TM II flow cytometer, and data analysis was determined using a FlowJo program. Results: The Raman spectroscopy results showed spectra consistent with viable cells. These findings were corroborated using fluorescence microscopy and flow cytometry techniques, confirming high cellular viability. Conclusions: The analyzed extracts exhibited low cytotoxicity, suggesting that they could be safely applied on enamel for remineralization purposes. The use of nanobiochips for SERS effect improved the cell viability assessment.

show abstract

Systematic review of epidemiological and toxicological evidence on health effects of fluoride in drinking water

Cited by 17 publications

References 100 publications

Fluoride and children’s IQ: evidence of causation lacking

Fluoride and children’s IQ: evidence of causation lacking

Fluoride-Ion-Responsive Sol–Gel Transition in an L-Cysteine/AgNO3 System: Self-Assembly Peculiarities and Anticancer Activity

Evaluation of Ilex guayusa and Piper marginatum Extract Cytotoxicity on Human Dental Pulp Mesenchymal Stem Cells

Contact Info

Product

Resources

About