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Unraveling the impact of polystyrene microplastics with varying particle sizes and concentrations on lipid in vitro digestion and ex vivo absorption

Journal of Hazardous Materials 2025 4 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count. Score: 58 ? 0–100 AI score estimating relevance to the microplastics field. Papers below 30 are filtered from public browse.
Hongyu Zhu, Peng Wu, Zejun Hu, Zejun Hu, Haozhi Chen, Haozhi Chen, Ni Wang, Xiao Dong Chen

Summary

Researchers investigated how polystyrene microplastics of different sizes and concentrations affect fat digestion and absorption using laboratory and tissue-based models. They found that microplastics interfered with the digestive process by interacting with digestive enzymes and bile salts, and that smaller particles at higher concentrations had the greatest inhibitory effect on fat absorption. The findings suggest that microplastics consumed with food could alter how the body processes dietary fats.

Polymers
Body Systems
Models
Study Type In vitro

The contamination of microplastics (MPs) in food has become a global concern due to their ingestion through the food chain and associated health risks. However, the impacts of MPs on lipid digestion and absorption remain poorly understood. This study investigates the effects of MPs on soybean oil in vitro digestion and ex vivo absorption, focusing on particle size (small ∼30 μm, medium ∼50 μm, and large ∼100 μm) and concentration (0.32, 0.64, and 1.28 mg/mL). During digestion, MPs interacted with digestive components, forming rough surface coronas and promoting aggregation, with mean size of small-sized MPs increasing by up to 57.9 %. The presence of MPs inhibited soybean oil digestion and pancreatic lipase activity in a concentration- and size-dependent manner. At 1.28 mg/mL, smaller MPs (∼30 μm) caused the most pronounced inhibition, reducing free fatty acid (FFA) release to 65.2 %, compared to 71.1 % for medium-sized MPs and 76.5 % for larger MPs. Pancreatic lipase activity similarly declined to 72.0 % with smaller MPs versus 83.0 % with larger MPs. In the ex vivo rat small intestine model, smaller MPs significantly impaired FFA absorption, with rates dropping from 43.4 % (no MPs) to 20.2 % with small MPs and 31.2 % with large MPs at the highest concentration. Fluorescent microscopy revealed that MPs, particularly smaller ones, adsorbed digestive enzymes and FFAs, forming physical barriers that hindered lipid migration toward intestinal villi. These findings provide mechanistic insight into how MPs disrupt lipid digestion and absorption, highlighting potential health risks of microplastic exposure.

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