Researchers' tips:

How to avoid ingesting too much microplastic

(Bild: [e-mail])

As several studies have already shown, increasing amounts of microplastics are accumulating in the human body. The load in the brain is particularly high. "Microplastics are ubiquitous in the food we eat, the water we drink and the air we breathe," write three Canadian researchers in a recent assessment of the latest findings and show how intake of the tiny particles can be drastically reduced.

The drastic increase in the concentration of plastic in the brain in just eight years is extremely worrying, said the commentary's lead author, Nicholas Fabiano from the University of Ottawa. Particularly small particles, less than 0.2 micrometers in size, were discovered in the brain. They consisted mainly of polyethylene, which is found in many everyday objects. Due to their small size, they are able to cross the so-called blood-brain barrier.

The effects are still unclear. Microplastics are particles between one micrometer (0.001 millimetres) and five millimetres. Nanoplastic particles are smaller. 

Plastic bottles should be avoided
Everyone can reduce their own intake of nanoplastics and microplastics, explain Fabiano and his colleagues. For example, if a person only consumes water from plastic bottles, they can absorb more than 20 times as many particles as someone who only uses tap water, the researchers write, referring to an earlier study. Water from glass bottles also contains more plastic particles than tap water, as researchers write in an analysis of 21 studies. This could be caused by bottling processes, among other things.

(Bild: AFP)

Plastic tea bags as another source
Another source of micro- and nanoplastics is plastic teabags. According to the researchers' commentary, letting a plastic tea bag steep at 95 degrees can release considerable quantities of these. It is therefore better to avoid such teabags. 

Avoiding plastic containers for food could also be effective. "Heating food in plastic containers - especially in the microwave - can release large amounts of micro- and nanoplastics," warned co-commentator Brandon Luu from the University of Toronto. Even long-term storage at room temperature or in the refrigerator leads to a significant release of particles, according to the researchers. "Using glass or stainless steel containers instead of plastic is a small but significant measure to minimize exposure," Luu said. 

Industrially processed food is more contaminated
Canned food can contain substances derived from plastics, such as bisphenol-A (BPA). In one study, test subjects were given canned soups for five days in a row, whereupon their BPA levels in urine increased many times over. The authors of the commentary also emphasize: "However, the duration of these BPA peaks and their health effects are unclear and require further research." Another US study has shown that highly processed foods contain significantly more microplastics than minimally processed foods. 

Still too few studies on effects on the body
There is evidence from cell culture and animal studies that the plastic particles can promote inflammation, immune disorders, an altered metabolism, abnormal organ development and cancer, among other things, the commentators write. However, the data situation is still poor. Large-scale human studies are needed to determine the potential health risks of microplastics. At the same time, studies should better evaluate the effectiveness of various reduction strategies.