Microplastics in our diet: A growing concern for human health

Abstract

Microplastics (MPs), particles smaller than 5 mm, are widely distributed in the environment, raising concerns about their long-term human health impact. MPs can enter the human food chain through various sources, including drinking water, salt, plant-based derived products, animal-based derived products (especially seafood), alcoholic beverages, and packaged food. Once in the human body, MPs have been detected in various biological tissues and secretions, such as feces, blood, semen, breastmilk, thrombi, colon, atheroma, and liver, highlighting their capacity for bioaccumulation. The most commonly identified polymers include polyethylene (PE), polypropylene (PP), and polystyrene (PS), along with others such as polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polymethyl methacrylate (PMMA). This review presents a perspective on underexplored food contamination by MPs, discussing the presence of these plastic fragments in human biological systems and discussing in vivo studies that investigate their potential health risks. Emerging evidence links MPs to inflammatory responses, oxidative stress, and cellular dysfunction, potentially contributing to gastrointestinal disorders, neurotoxicity, reproductive toxicity, and cardiovascular risks. Key knowledge gaps persist for understanding health impacts under environmental relevant conditions, particularly regarding long-term exposure, particle size effects, chemical composition, and interactions with environmental pollutants. Addressing these challenges requires the development of advanced experimental models and human-relevant tissue studies, to improve understanding of MPs bioaccumulation, toxicity, and mechanisms of action. This work underscores the urgency of mitigating MP exposure and advancing studies to better understand their real implications for human health.