Mycotoxins, a part of the dietary exposome: a challenge for toxicologists

International audience

anglais. Throughout our lives, humans are exposed to a wide range of food contaminants, bacterial toxins and neoformed products from our diet: this is the concept of the dietary exposome. Among natural food contaminants, mycotoxins being the most frequently occuring natural ones. Mycotoxins are secondary fungal metabolites produced mainly by Aspergillus, Penicillium and Fusarium. Mycotoxins co-contamination is confirmed by the co-occurrence of these toxins in food and by co-exposure monitoring survey. The co-occurrence of mycotoxins in food is explained by three different reasons: (i) most fungi are able to simultaneously produce several mycotoxins, (ii) commodities can be contaminated by several fungi simultaneously or in quick succession, and (iii) the complete diet comprised different commodities. In practice, the co-occurrence of mycotoxins represents the rule and not the exception. Unfortunately, the data on the combined toxic effects of mycotoxins are limited and therefore, the health risk from exposure to a combination of mycotoxins is incomplete. Most of the studies concerning the toxicological effect of contaminant have been carried out taking into account only one compound. A synergistic effect between mycotoxins of the trichothecene family mycotoxins was observed both for intestinal cytotoxicity and inflammatory response and the synergy was already seen at low doses. Besides mycotoxins, other contaminant can be found in our diet such as heavy metals, bacterial toxins, pesticides or neoformed products … Thus, the combined exposure to the mycotoxin deoxynivalenol and Cadmium was also studied in several human cell lines and interactions were specific to the target organ. Moreover, the interaction between deoxynivalenol and genotoxins, present either as food contaminant or as toxins from our microbiota, was also investigated. Although not carcinogenic, DON exacerbates DNA damage induced by genotoxins such as bacterial toxins, pesticides or reference genotoxic compounds, suggesting a role in colorectal cancer.Altogether, these data demonstrated that (i) mycotoxin cocktails can lead to synergistic interaction and that (ii) mycotoxins also interact with other food contaminants (heavy metal, genotoxins…) and with the intestinal microbiota. Thus, contaminations should be taken in the global context of the dietary exposome.