Microplastics in Canned Food Linings and Possible Effects on Intestinal Motility: A Review of the Mechanisms and the Present Evidence

Canned foods are an important component of the global food supply, and the possible role of internal polymer can linings in human exposure to microplastic particles is not well understood. Although past studies have emphasised the chemical release of food-contact materials additives like bisphenol A, relatively little effort has been made on the potential physical release of micro- and nanoplastic particles in can linings and their physiological consequences on the gastrointestinal system. In this critical review, the existing experimental evidence was summarised and showed that exposure to microplastics relates to inflammation of the intestine, disruption of epithelial integrity of barriers, and changes in gut microbial community. Despite the current lack of evidence that directly implicates microplastics generated by canned food linings in particular, in alterations in intestinal motility, these biological outcomes do offer a mechanistic underpinning by which a hypothesis can be constructed. Accordingly, this review proposes a conceptual framework in which microplastics can affect intestinal motility through three interrelated pathways, which include inflammation-associated neuromuscular dysfunction, microbiome-mediated gut-brain axis modulation, and possible direct mechanical or sensory effects on the intestinal wall.