From The Guardian, November 27, 2023:

Research suggests bacteria in fermented foods may ameliorate some inflammation that microplastics promote in our system.

The topic of microplastics and our bodies is disconcerting. It seems like there’s little we can do about the tiny particles that have found their way into our blood, brains, lungs and beyond.

Encouragingly, a body of research now suggests we have at least one cheap, accessible line of defense against the damage associated with plastics in our digestive systems: probiotics. There is already evidence that these bacteria, found in fermented foods such as yogurt, sauerkraut and kimchi, support our immune systems and offer benefits that can alleviate gastrointestinal issues, inflammation and allergies. Now, it seems they could help us fight some effects of these pervasive petrochemical particles.

How do microplastics affect our stomachs?

Multiple studies have demonstrated that nanoplastics can enter our blood and organs and cross the mucosal barrier into our gastrointestinal tracts.

While more research is needed to determine the relationship between plastic and gastrointestinal disorders, preliminary findings suggest ingesting plastic isn’t doing us any favors.

A Tufts University study published this June found that high concentrations of polystyrene particles “significantly triggered the secretion” of inflammatory proteins called cytokines in in-vitro gut models. Cytokines are linked to inflammatory bowel diseases (IBD) including Crohn’s disease and ulcerative colitis, which have been rising globally from 3.7m cases in 1990 to more than 6.8m in 2017.

A causal link is not yet clear, because factors such as a diet high in ultra-processed foods, smoking and exposure to air pollution are also linked to IBD. But researchers increasingly believe microplastics, which are filled with various harmful chemicals including additives like bisphenol A (BPA), flame retardants and phthalates, also play a role.

For a January 2023 study published in the Journal of Hazardous Materials, French researchers added microplastics to a modeled gut biome and observed that beneficial bacteria declined, while two strains of bacteria associated with disease increased. A 2021 Chinese study determined that people with inflammatory bowel disease have 50% more microplastics in their feces than those with healthy stomachs.

When gut microbes feed on or adhere to microplastics in the stomach, it can alter their chemical composition, affecting bacterial diversity and causing other “negative effects, including changes in gut metabolic profiles and inflammation”, wrote the authors of a 2022 Spanish study. In more extreme cases, they said it could contribute to a condition called “dysbiosis”, in which bad bacteria outnumbers the good in our stomachs. Dysbiosis can increase the likelihood of developing other serious conditions, including diabetes, Crohn’s disease and colorectal cancer.

How do probiotics and microplastics interact?

Unfortunately, probiotics can’t magically pluck plastic particles out of our bodies. However, some research suggests that the good microbes could help ameliorate some of the toxicity and inflammation plastics promote in our gastrointestinal systems.

This summer, a team of Iranian researchers published a review study exploring how probiotics could protect against the adverse effects of plastics on gut flora. Probiotic micro-organisms may interact with polystyrene particles “to modify their toxic effects on different tissues”, they wrote.

For more on this, see The Guardian.