Fluoride concentration in semi-solid infant foods and institutional soups in a Southern Ecuadorian population: implications for dental fluorosis risk

Background: Excessive systemic fluoride (F⁻) exposure during early childhood is a recognized risk factor for dental fluorosis. In addition to drinking water, commercially processed infant foods and institutional meals may contribute to total dietary fluoride intake. This study aimed to determine and compare fluoride concentrations in commercial infant foods and semi-solid institutional preparations in Cuenca, Ecuador, and to estimate their potential contribution to dietary fluoride exposure among children aged 6 months to 3 years. Methods: A total of 41 samples, including commercial infant foods and institutional soups, were analyzed. Fluoride concentrations were determined using the hexamethyldisiloxane (HMDS) acid microdiffusion technique coupled with a fluoride ion-selective electrode (ISE). Fluoride intake was estimated for a standardized 125 mL serving and expressed as fluoride intake per serving, body weight-adjusted intake, and percentage of the European Food Safety Authority (EFSA) tolerable upper intake level (UL). Statistical significance was established at p < 0.05. Results: Institutional soups exhibited significantly higher and more variable fluoride concentrations than commercial infant foods, ranging from <LOD to 2.66 mg F⁻/L and from <LOD to 0.73 mg F⁻/L, respectively (p < 0.001). Fluoride intake per serving reached 0.333 mg in institutional soups compared with 0.091 mg in commercial infant foods. The estimated fluoride intake represented 4.92% of the EFSA UL per serving for institutional soups and 0.16% for commercial infant foods. Conclusions: Institutional semi-solid preparations contained higher and more variable fluoride concentrations than commercial infant foods, indicating a greater potential contribution to dietary fluoride exposure during early childhood. These findings highlight the importance of monitoring fluoride concentrations in foods intended for young children, particularly in institutional settings, to strengthen dietary fluoride surveillance and support strategies aimed at preventing dental fluorosis while preserving the caries-preventive benefits of fluoride.

Fluoride; Infant foods; Semi-solid foods; Dietary exposure; Dental fluorosis

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