A system for magnetic assessment of body iron stores includes excitation coils adapted to generate multiple-frequency alternating current (AC) magnetic fields and to partially magnetically saturate iron. The system further includes one or more detection coils adapted to detect the AC magnetic fields. A signal processor uses lock-in amplifiers and linear regression to measures changes to the multiple-frequency AC magnetic fields caused by proximity to iron. A method for magnetic assessment of body iron stores includes generating multiple-frequency AC magnetic fields and detecting changes to the AC magnetic fields caused by proximity to iron. The method further includes partially magnetically saturating iron, thereby generating non-linear responses, harmonic frequencies, and intermodulation frequencies.
