Clarification of tolerable daily intake of cadmium with food products based on health risk criteria

Cadmium is one of the most hazardous environmental toxicants with cumulative properties and polytropic toxic effects on the human body. Cadmium is predominantly administered orally with food products and to a lesser extent with drinking water. Even low-dose repeated exposure to cadmium leads to the toxicant accumulating first of all in the kidneys and producing nephrotoxic effects. Maximum permissible levels (MPLs) were fixed for cadmium in food products to ensure their safety for human health. Tolerable daily intake (TDI) is the scientific foundation for establishing MPL.

Various international organizations have proposed different TDI for cadmium. The existing spread of TDI values is caused by various methodological approaches employed to substantiate them and this necessitates clarification of safe levels of cadmium exposure.

The aim of this study was to clarify cadmium TDI upon alimentary intake with food based on an acceptable level of health risk.

We performed systemic analysis of data on reference doses using information provided by international organizations (EFSA, JECFA, U.S. FDA, U.S. EPA) and taken from research publications accessible in PubMed and Scopus. The TDI value was clarified in conformity with the Eurasian Economic Commission methodology using modifying factors and subsequent veri-fication by evolution modeling.

Comparative analysis of cadmium reference doses revealed TDI variability from 0.21 (U.S. FDA) to 1.0 µg/kg b.w./day (U.S. EPA) upon oral intake. NOAEL was chosen as the point of departure based on complex assessment of examined meth-odological approaches. NOAEL was established per results of an epidemiological study and used as the lower limit of the U.S. FDA TRV range (TDI analog) per the effect produced on the kidneys.

In conformity with the Eurasian Economic Commission methodology, modifying factors were applied to the selected value; they covered extrapolation from the simulation mode onto real life conditions (4) and a study group in intraspecies (2) The calculated TDI value equaled 0.026 µg/kg b.w./day.

Verification by evolution modeling confirmed the protective nature of the calculated TDI. The obtained TDI value ensures the minimal risk of developing non-carcinogenic effects upon repeated exposure to cadmium in food products and can be recommended for use when establishing safe standards for cadmium contents in food products.