Occurrence of fluoride in breast milk: a worldwide systematic literature review and human health risk assessment by Monte Carlo simulation

Fluoride is recognized for its dental health benefits; however, excessive intake during infancy may pose risks such as dental fluorosis. This review evaluated fluoride levels in breast milk (BrM), influencing factors, and potential health effects in infants. The methodology involved searching PubMed, Scopus, Web of Science, IranDoc, Science Direct, and Google Scholar for studies published from 1974 to 2025. The search strategy included Medical Subject Headings (MeSH) terms and free-text keywords - such as "fluoride," "breast milk," "breastfeeding," 'human,"and "level," along with other relevant terms - combined with Boolean operators (AND/OR) for a comprehensive literature search. Inclusion criteria: peer-reviewed studies with original data on fluoride in BrM. Exclusion criteria: informal reports, reviews, and studies without primary data. Of the 204 records, 9 studies were included in the final analysis. Lacking raw data, values were re-simulated in Excel (2016) using mean, standard deviation, and sample size. Results showed that the mean fluoride in BrM met the European Food Safety Authority (EFSA) guideline (100 µg/L) in 12 of 19 cases (63.2%), with 36.8% outside this range. The health risk assessment showed that, for one-month-old infants, the hazard quotient (HQ) exceeded the permissible limit (HQ = 1) in 7 of 19 cases (36.8%).