Bioaccessibility of metals in food supplements: protocols and facts

Abstract This study evaluated the bioaccessibility of essential (Ca, Cu, Fe, K, Mg, Mn, Mo, Na and Zn) and non-essential (Al, Ba, Cr, Sr and V) elements in food supplements (vitamins and/or minerals and botanicals). Extraction using in-vitro methods (Unified BARGE Method—UBM and INFOGEST) was evaluated allowing a comparison of protocols and using inductively coupled plasma optical emission spectrometry (ICP OES). Bioaccessibility values revealed differences among the elements in different types of food supplements. The limits of quantification (LOQs) obtained for some elements were relatively high for both methods due to the composition of the digests, which drastically impaired bioaccessibility assessment. As a result, most elements presented fractions lower than the LOQ, regardless of the sample. This is an important limitation promoted by interferences when analyzing these extracts by ICP-based techniques. A simple extraction using 1 mol L −1 HCl was evaluated, considering that HCl is present in the solutions used in both protocols. Leaching was observed for the same elements using only the HCl solution.