Microplastics found in contaminated food can reach the brain

Microplastics present in contaminated food and ingested during a meal can migrate from the intestine to other organs , including the brain. The discovery comes from a recent study published in the journal Environmental Health Perspectives and shows that these particles can have a significant impact on human health.

Microplastics are small particles, smaller than 5 millimeters, of plastic, which can be released from food packaging, drinks, tires, clothing and pipes. Several studies have already shown that these plastic fragments are contaminating water and soil, even reaching the food we consume.

“Over the past few decades, microplastics have been found in the ocean, in animals and plants, in tap water and bottled water,” says Eliseo Castillo, associate professor in the Division of Gastroenterology and Hepatology in the Department of Internal Medicine at the Faculty of Medicine of UNM (University of New Mexico), in a statement. “They seem to be everywhere.”

The scientists estimate that they will be consumed average, 5 grams of microplastics per week , which is equivalent to the weight of a credit card. Given this scenario, Castillo and other researchers decided to investigate how these particles can act in the gastrointestinal tract and the intestinal immune system.

To do this, over a period of four weeks, researchers placed microplastics in drinking water that would be ingested by rats. The amount was equivalent to the estimated amount humans ingest of these fragments per week.

According to the searchyou microplastics migrated from the intestine to the tissues of the liver, kidneys and even the brain . The study also showed that the particles altered metabolic pathways in the affected tissues. For researchers, these findings indicate that these plastic fragments can cross the barrier and infiltrate other tissues.

In Castillo's view, the results of the study are worrying. “These mice were exposed for four weeks,” he says. “Now think about how this compares to humans if we are exposed from birth to old age.”

Microplastics may be influencing the immune system

In a previous study, published in 2021Castillo and other UNM researchers discovered that macrophages — immune cells that work to protect the body from foreign particles — that ingested microplastics had their function altered, releasing inflammatory molecules.

“[Os microplásticos] They are changing cell metabolism, which can alter inflammatory responses,” says Castillo. “During intestinal inflammation – chronic disease states like ulcerative colitis and Crohn’s disease, which are both forms of inflammatory bowel disease – these macrophages become more inflammatory and are more abundant in the intestine.”

The next phase of the researchers' investigation, led by postdoctoral fellow Sumira Phatak, aims to explore how diet is involved in the absorption of microplastics. Castillo hopes that the research will help discover the impacts that microplastics are having on human health and encourage changes in the way society produces and filters plastics.