Thoerig et al. 2025 — Toxic elements and PFAS in U.S. human milk and infant formula: systematic review
This American Journal of Clinical Nutrition systematic review by a 15-author team led by Thoerig and O’Connor (Agriculture, Food, and Nutrition Evidence Center, Fort Worth) synthesizes the U.S. evidence base on As, Cd, Pb, Hg, and per-and-polyfluoroalkyl substances (PFAS) in human milk and infant formula. The review applies systematic review methodology (PRISMA-style inclusion criteria, predefined search and screening protocols) to the U.S.-applicable peer-reviewed and government-data corpus through 2024-2025, producing a summary distribution by matrix and analyte. As of the 2025 publication date, this is the most current and most comprehensive U.S. systematic review of toxic elements in infant feedings and is directly applicable to HMTc milk-based and soy-based infant formula row evidence assessment.
Key conclusions
The systematic review documents that infant formula concentrations of As, Cd, Pb, and Hg vary substantially across U.S. market products and that human milk concentrations of these elements are generally lower than reconstituted formula concentrations on a per-serving basis (consistent with the Soto-Ocaña 2024 mechanistic finding that formula-fed infant gut metal levels exceed breastfed levels). Per-analyte and per-matrix summary statistics are reported; the paper is the canonical citing reference for the U.S. infant-formula toxic-elements evidence base post-2020 FDA Closer-to-Zero initiative.
Implications
- Certification: Highest-tier secondary-synthesis source for HMTc milk-based and soy-based powdered formula and ready-to-feed liquid formula rows. Should be used as a synthesis citation that bounds the U.S. literature, not as a primary occurrence source for benchmark-pool admission (the underlying primary studies, including Carignan 2015, Carignan 2016, Jackson 2012, FSA 2016, FDA 2026, Dabeka 2011, Almeida 2022, and others already on the wiki, supply the sample-level data).
- Courses: Strong recent example of systematic-review methodology applied to the infant-feeding toxicology question.
- App: Supports the formula-vs-breastmilk per-serving exposure estimate that the app’s risk-scoring layer will use.