Microplastics and The Gut Microbiome

Microplastics, formed as plastic waste degrades, contaminate drinking water and food, making ingestion a major exposure route for humans.

Once considered harmless, growing evidence links microplastics to gut microbiota disruption, inflammation, and beyond the gut, to the immune and nervous system function.

With growing evidence linking gut health to neurodegeneration, microplastic exposure may contribute to the increasing prevalence of diseases.

Microplastics, first identified in 2004 as tiny plastic fragments, have since become recognized as pervasive global contaminants. These particles, often less than 5mm in size and even microscopic, originate from a variety of sources such as cosmetics, paint, textiles, tires and the breakdown of larger plastic debris. They are now found in a wide range of environments, from the ocean's surface to mountain peaks, and are present in many species, including humans. As a result, microplastics are increasingly being detected in food, water and air, with growing concerns about their potential impact on health. Regulatory actions are emerging globally, with countries prohibiting microplastics in cosmetics and implementing measures like filters in washing machines. However, with emissions expected to rise significantly in the coming decades, the long-term environmental and health risks remain uncertain (Thompson et al., 2024).

Microplastic-induced gut dysbiosis disrupts metabolic, immune and nervous system functions, altering key biological pathways related to lipid and hormone metabolism, neurotoxicity, inflammation and disease progression. Research has linked microplastic exposure to increased intestinal permeability, which allows harmful bacterial components like lipopolysaccharide (LPS) to enter circulation, triggering systemic inflammation (Sofield et al., 2024). Miroplastics may also act as carriers for pollutants or pathogens (Demarquoy, 2024),further disrupting gut microbial communities. These disruptions can have far-reaching effects on immune function, nutrient metabolism, and overall health. As evidence continues to mount, microplastic ingestion is increasingly associated with gut-brain axis disruptions and broader systemic effects. Microplastics can harm the gut, which may lead to kidney damage. 

Researchers identified genes encoding plastic-degrading enzymes in human stool samples, regardless of microplastic contamination. This suggests that microbes capable of breaking down plastics may already be present in human consumables and enter the gut through ingestion. However, they hypothesize that a significant impact on gut microbiome composition may only occur if microplastic contamination surpasses a certain threshold (Nugrahapraja et al., 2022).

Microplastics can cross the intestinal barrier and accumulate in tissues, with smaller particles (<5 μm) penetrating more easily than larger ones. Research shows that microplastic shape also influences absorption, as irregular, fragmented particles—more representative of environmental microplastics—cause greater membrane damage and accumulate at higher rates than smooth, spherical microplastics commonly used in studies. While the exact mechanisms of microplastic transport remain unclear, evidence suggests they may bypass cellular internalization and instead move between intestinal cells through paracellular transport. Pre-existing gut barrier damage—whether induced by diet, inflammation, or microplastic exposure—likely plays a key role in facilitating their entry into circulation (Sofield et al., 2024).

• Endocrine Disruptors

Endocrine disruptors are natural or synthetic chemicals that interfere with the body’s hormonal system, potentially causing health issues. These chemicals are found in everyday products like food packaging, cosmetics, pesticides and toys, with exposure occurring through air, diet, skin and water. Common endocrine disruptors include BPA, a common microplastic, phthalates, PFAS, dioxins and atrazine, among others. Endocrine disruptors can mimic or block hormones, affecting growth, reproduction and overall health. While these chemicals cannot be entirely avoided, reducing exposure through informed choices may help minimize potential risks. Even in low doses, endocrine-disrupting chemicals may be unsafe (National Institute of Environmental Health Sciences, 2024).

Researchers have found microplastics in human brains at significantly higher levels than in other organs (Nihart et al., 2024). Their findings suggest that plastic accumulation in the brain is increasing over time, rising by 50% in just the past eight years (Haederle, 2025). Microplastics and other nanoplastics are also being explored in the context of Parkinson’s disease. These tiny plastic particles found throughout the environment have been detected in human blood, raising concerns about their potential health effects (NIH, 2023). Alpha-synuclein, a protein that misfolds and accumulates in the brains of Parkinson’s disease patients (Stefanis, 2012), was found to bind to polystyrene nanoplastics, leading to the formation of abnormal protein structures linked to the disease. Researchers observed that both alpha-synuclein fibrils and nanoplastics can enter neurons, where they disrupt cellular waste disposal processes, potentially accelerating Parkinson’s progression.

To reduce exposure to microplastics and other toxins in food, it’s best to avoid microwaving in plastic, as heat can cause harmful chemicals like BPA to leach into food. Instead, using ceramic or glass is a safer alternative. Choosing glass or stainless steel water bottles over plastic helps minimize exposure as well. Buying organic whenever possible can reduce pesticide intake, and while access to organic food varies, making informed choices can help. Cutting back on red meat is another way to lower chemical exposure since toxins tend to accumulate in fatty foods, and it also has environmental and health benefits. Eating more grains, fruits, and vegetables instead of foods higher up the food chain further limits toxin consumption. When replacing household items, it’s more practical to transition gradually from plastic containers and non-stick cookware rather than discarding everything at once. For non-toxic cleaning, simple solutions like vinegar and water or baking soda work just as well as commercial products, and using a HEPA-filter vacuum can help control dust and other contaminants in the home (González, 2024).