SynthesisNutrition reviews2025
Effect of Fluoride on Gut Microbiota: A Systematic Review.
Synthesis in Nutrition reviews, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
1 citing paper in PubMed.
- Chronic Excessive Exposure to Fluoride Impairs the Intestinal Mucosal Barrier to Cause Inflammatory Response and Microbiome Dysbiosis in Rats.Biological trace element research · 2026Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors.
Funding
Abstract
contextFluoride can prevent dental caries by inhibiting demineralization and promoting remineralization of teeth while affecting the physiology of oral microbiota, thus inhibiting cellular enzymes. However, the effect of systemic fluoride on gut microbiota is unknown.
objectiveTo explore the impacts of systemic fluoride on gut microbiota composition and abundance and associated functions such as gene and metabolic regulation. DATA SOURCES: A systematic database search was conducted of MEDLINE, Web of Science, Scopus, PubMed, CINAHL, and Embase to find articles on studies reporting the effects of fluoride on gut microbiota. DATA EXTRACTION: Forty-nine studies were included (n = 42 in animals, 4 of humans, 3 in vitro studies) after screening for title, abstract, and full text using Covidence to check against eligibility criteria. Data were extracted using Covidence and study quality was assessed using the Mixed Method Appraisal Tool by 2 reviewers independently. DATA ANALYSIS: Two human studies of dental fluorosis and 1 of patients with breast cancer (intestinal fluorine-18 fluorodeoxyglucose uptake) showed significant differences in gut microbial composition, with increased relative abundance of Acidobacteria and Proteobacteria, and decreased abundance of Firmicutes and Bacteroidetes. An ex vivo study of human feces indicated that ≤ 2 mg L-1 NaF might boost "health-associated" taxa, but concentrations (≥ 10 mg L-1 NaF) could increase the ratio of some unhealthy microbes after 24 hours. The animal studies examined the effects of high fluoride doses in water and diet (50-1200 mg L-1 NaF) for long-term (1-6 months) and short-term (6 hours to 7 days) exposure, with all showing a significant disturbance in the Firmicutes to Bacteroidota ratio.
conclusionIn humans, high doses potentially may be detrimental to the microbiome, whereas ≤ 2 mg L-1 NaF had positive effects. Similarly, in animals, ≥ 50 mg L-1 NaF was unsafe, whereas ≤ 25 mg L-1 NaF had harmless effects. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration No. CRD42022347357.
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Registered trials
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