Clinical Relevance of Heavy Metals Bioaccessibility in Leafy Vegetables: Implications for Dietary Risk Assessment Using an In vitro Digestion Model

Introduction: The primary purpose of this research was to investigate the amount and human health risk (HHR) related to some heavy metals (HMs) in leafy vegetables based on the total concentration mode (TCM) and bioaccessible concentration mode (BCM). Methods: Seven types of leafy vegetables were collected, and then, 105 raw and 35 humandigested leafy vegetable samples were selected. These samples were analyzed for HMs by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), and HHR assessments were performed using the Monte Carlo simulation method. Results: The bioaccessibility average of the HMs between leafy vegetables varied from 23.8 to 86.8%, with significant differences (P>0.001). The estimated hazard index associated with the probabilistic non-carcinogenic risk (PNCR) for all HMs, based on the TCM (1.38), was higher than the acceptable level (1). The PNCR value based on the BCM (=0.59) was, in turn, significantly lower than the limit. This was also true for probabilistic carcinogenic risk (PCR), as the cancer risk values for the TCM and BCM were estimated to be 2.7×10 -3 and 8.4×10-4, respectively, indicating a difference between the two estimations. Discussion: These findings highlight the importance of BCM-based risk assessments in dietary studies, as they offer more accurate and actionable insights into health risks. Relying on TCM for Human Health Risk Assessments (HHRA) may lead to overestimations that misguide regulatory decisions. Conclusion: A HHRA based on the BCM is more realistic, and health decisions and protective measures are more accurate. It is, therefore, recommended that researchers use this method for HHRA of HMs in various foods.