Biomarkers of Mycotoxin Exposure in Humans

Abstract

Mycotoxins are secondary metabolites of certain species of fungi and they are frequent contaminants of agricultural products. Contamination of humans by dietary intake may result in various pathophysiological effects, such as nephrotoxicity, gastro-enteric distress, hyperestrogenic conditions, cancer etc.. Therefore, exposure of human population to these compounds needs to be controlled and assessed. Risk assessment of a toxicant is evaluated with the help of biomarkers which provide information on biological responses following contamination (biomarkers of effect) or allow the quantification of the toxicant or its biotransformation products in body fluids (biomarkers of exposure). The biomarkers are needed to establish the oral dose (intake from food), the internal dose (biologically active) and the dose-response relationship. Here we describe a series of biomarkers of exposure and effect for aflatoxins, fumonisins, ochratoxin A, zearalenone and deoxynivalenol. For aflatoxins, except the possibility of quantifying the original chemicals per se in biological fluids, the hydroxylation products AFM1 and AFM2 are good indicators of internal exposure, while the albumin and DNA adducts are markers of effect. Ochratoxin A is easily detectable in blood, urine and milk, but its considerably long half-life makes it difficult to correlate with the level of exposure, The main biomarker for fumonisins is the sphinganine:sphingosine ratio, while for deoxynivalenol exposure is evaluated by its presence in urine. For zearalenone there is no reliable biomarker.