A postbiotic may limit our absorption of microplastics, according to the first human trial of a microplastic-removal supplement. It uses the rough surface of dead bacteria to attract microplastics, preventing them from entering cells.
Microplastics, which are less than 5 millimetres long, are ubiquitous in the environment and have been detected throughout the human body. Research has shown that people with arterial plaques containing microplastics are more than four times as likely to have a heart attack or stroke than those with plastic-free plaques. Higher concentrations of microplastics have also been reported in the brains of people with Alzheimer’s disease. However, neither finding proves that microplastics cause these conditions.
“We don’t really know what microplastics do, but we do know they don’t belong in the human body,” says , co-founder and chief scientific officer at Quorum Innovations in Florida, the biopharmaceutical company that developed the postbiotic, a supplement made from the parts or byproducts of dead bacteria. “If we have a reasonably safe and fairly inexpensive way of modifying [potential] risks, then maybe we shouldn’t wait 20 years for a more conclusive answer before we do that.”
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Berkes and her team created the postbiotic, called Qi601, by growing the bacterium Limosilactobacillus fermentum, killing it with heat and collecting its cell walls. They then incubated microplastics and Qi601 together and found the plastic particles stuck to the walls’ rough surfaces.
To guage whether this would work in the body, they added nanoplastics – smaller than 0.001 millimetres – and Qi601 to fluids resembling different parts of the digestive system and found that up to 92 per cent of them spontaneously bound to the postbiotic.
The researchers also exposed human intestinal-like cells to nanoplastics with and without the postbiotic and found that when Qi601 wasn’t present, nanoplastics accumulated within cells and on their surfaces. When Qi601 was added, significantly less nanoplastics were visible inside or on the cells, suggesting that the postbiotic mopped them up before they could be absorbed.
In another part of the experiment, the researchers wanted to see whether Qi601 could remove nanoplastics already inside cells. They first exposed cells to nanoplastics in the lab for 24 hours and later added Qi601, which reduced the number of plastic particles inside the cells by 43 per cent. This seems to happen by Qi601 capturing plastic when it is transported in and out of cells during a process called vesicle recycling.
Finally, one participant chewed commercial gum, which releases numerous microplastic particles into saliva, until they had collected 10 millilitres of saliva. The researchers then repeated the experiment but placed 10 milligrams of powdered Qi601 in the participant’s mouth after 5 seconds of chewing. Analysis of the saliva showed 2152 freely floating plastic particles after chewing gum alone, compared with 185 when Qi601 was added.
“Our results represent the first demonstration of microplastics being bound by a microplastic mitigant in [people],” says Berke. However, the study hasn’t shown that the particles were prevented from entering cells in the human gut or that they were excreted. The team also notes that the results could be affected by the presence of food, immune cells or the complex architecture of the gut.
at the Norwegian University of Science and Technology also points out that people are constantly exposed to microplastics through food, water and air. “[The postbiotic] would not remove the inhaled particles, a major source of exposure, nor would it address the continuous nature of exposure,” he says. “Reducing these exposures at the source is much more efficient in protecting health, rather than trying to remove plastic particles from the body retrospectively.”
bioRxiv
