Single hair analysis by X-ray fluorescence spectrometry detects small changes in dietary zinc intake: A nested randomized controlled trial

This study demonstrated that single hair analysis using X-ray fluorescence (XRF) spectrometry can detect small changes in dietary zinc intake, offering a sensitive, non-invasive method to monitor zinc levels. Conducted on 123 adolescent girls in Pakistan, the study found that a modest increase in zinc intake of 1.5 mg per day over 6 months resulted in a significant increase in the Zn:S ratio in hair, indicating increased zinc uptake. The intervention group showed greater increases in zinc and sulfur counts compared to the control group. The study highlights the potential of XRF for evaluating dietary zinc interventions, although further work is needed to establish a calibration curve for converting Zn:S ratio data to zinc content per gram of hair.