Gut homeostasis and microbiota under attack: impact of the different types of food contaminants on gut health

Food contaminants represent food constituents that are accidentally introduced during food preparation cycle. In addition to their direct toxic effects on human health at different levels, they influence both gut microbiota composition and function. This often leads to metabolic disorders linked to many aspects of the human body. Foods are poisoned with physical, chemical, or biological factors either in agriculture or during processing steps. These include naturally occurring compounds such as mycotoxins, agricultural chemicals such as pesticides and antibiotics, persistent organic pollutants, thermal process contaminants (e.g., furans, aromatic compounds, and nitrosamines), or heavy metals. These xenobiotics cause a wide range of toxicities. They also disturb gut homeostasis by inducing intestinal damage and inflammation and gut microbiota dysbiosis. We present herein the first comprehensive review of how food contaminants can specifically influence gut microbiota and intestinal homeostasis, and likewise via gut microbiota-mediated contaminants metabolism. The first part summarizes the different classes of food contaminants and their impact on gut microbiota and its homeostasis, while, the second part discusses the promising role of the gut microbiota in the biodegradation of these xenobiotics and the possible unfortunate exaggerated toxicities in some cases. Finally, we summarize the novel strategies to minimize toxic effects of food contaminants and future directions needed to explore the interactions between food contaminants and the gut microbiota.