Many potential health benefits are related to the consumption of marine organisms due to the presence of high amounts of beneficial bioactive compounds (e.g. polyunsaturated fatty acids, various peptides, minerals …). Therefore, these organisms are frequently used as base for several food supplements (FS). On the other hand, marine organisms are also known to contain high levels of arsenic (As), resulting in elevated As concentrations in FS with ingredients of marine origin, such as fish oil, krill oil or algae. Since human health risks are not related to the total As concentration but are species dependent, analysis of the relevant toxic As species in FS is mandatory for a correct risk assessment.
The aim of the present study was to make an exposure and risk assessment of As (species) resulting from the consumption of these types of FS, based on 60 samples collected in a Belgian market study. In this context, the determination of the most toxic fraction, inorganic arsenic (Asi) and the non-toxic fraction arsenobetaine (AB) is particularly important. In addition, we considered the ‘potentially toxic As fraction’ i.e. ‘Astot-AB’, consisting of not only Asi, but also As species with unknown toxicity, such as arsenosugars and arsenolipids which can occur in marine matrices, in particular in algae.
Analysis of Asi in algae by HPLC-ICP-MS is complicated by the presence of arsenosugars in these organisms. Routine methods for Asi analysis in terrestrial matrices do not automatically guarantee a separation of AsV and arsenosugars. The objective of this study was to optimize and validate a method to ensure a correct quantification of methylarsonate (MA), dimethylarsinate (DMA), AB and Asi in marine matrices. Arsenobetaine could not be determined on the same anionic column as the other species, therefore a method using a cationic column was needed to separate AB from other uncharged or cationic species.
Exposure to Asi, MA, DMA and ‘Astot-AB’ was calculated for each sample by multiplying the concentration of these compounds with the maximal recommended dose of the FS. Risks related to the intake of arsenic species in the food supplements were evaluated by comparing the calculated exposure to selected acute and (sub)chronic reference values. For Asi, a distinction was made between the general Belgian population and a sensitive population group, i.e. persons with an increased cancer risk. For the latter group a more severe reference value was applied. The risk evaluation for the chronic intake of Asi and the potentially toxic As fraction was carried out by calculating a margin of exposure (MOE), whereby MOE values > 100 were considered as ‘of concern’. Regarding MA and DMA no (sub)chronic risk was present, and no risk for acute toxicity of Asi was detected either. The intake of Asi was only of concern for sensitive groups in the case of chronic consumption of 24% of the tested FS based on algae. The intake of the potentially toxic As fraction was of concern in the case of chronic consumption of 19% of the tested food supplements based on algae, 6% of the tested food supplements based on fish oil and 67% of the tested food supplements based on krill oil.
These findings illustrate the need for more information regarding the toxicity of the potentially toxic arsenic species (mainly arsenosugars and arsenolipids), starting with a correct characterization of these species.
