Magnetite nanoparticles in the human gut - reflection of environmental pollution?

Magnetic iron oxide nanoparticles (MNPs) originating from anthropogenic sources are pervasive in the environment and capable of entering the human body via inhalation and ingestion. While anthropogenic MNPs are commonly linked to air pollution from combustion and industrial activities, the human gut serves as a one passageway for these particles, reflecting internalized exposure. In this study, fecal samples from Parkinson’s disease patients (n=12) and their healthy spouses (n=12) were analyzed using high-sensitivity magnetometry and transmission electron microscopy to characterize MNP abundance, grain size, and morphology. All samples contained considerable amounts of MNPs. Rounded combustion-derived particles, sharp-edged abrasion-derived particles and euhedral particles of apparent bacterial origin were obtained. MNP concentrations and morphologies were similar between patient and control groups. These findings provide proof-of-concept that fecal magnetometry can be used as a non-invasive approach for detecting and characterizing magnetic nanoparticles in human gut contents and exploring internalized exposure to pollution-derived MNPs.