Natural Food Preservative May Harm Beneficial Gut Bacteria

A common natural food preservative may be harming commensal bacteria that populate the gut microbiome, according to the results of a study published in ACS Chemical Biology. This preservative is called a lantibiotic (a term that combines the words lanthipeptide and antibiotic), and although it does destroy pathogens, it can also threaten healthy gut microbes.

“This study is one of the first to show that gut commensals are susceptible to lantibiotics, and are sometimes more sensitive than pathogens,” said Zhenrun Zhang, PhD, a postdoctoral scholar in the lab of Eric Pamer, MD, a professor of medicine and director of the Duchossois Family Institute at the University of Chicago (UChicago), in an article. “With the levels of lantibioticscurrently present in food, it’s very probable that they might impact our gut health as well.”

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Preservation is a longstanding tactic to keep food fresh. Natural preservatives such as salt, vinegar, sugar, and alcohol have been used throughout history to prevent food from spoiling, but recent innovations, including sodium benzoate, calcium propionate, and potassium sorbate, have expanded our preservation methods.

Lantibiotics are a type of lanthipeptide that has especially potent antimicrobial activity; lanthipeptides are bacteriocins, which are chemicals naturally produced by bacteria to kill microbial competitors. Because lantibiotics can eradicate pathogens, they have become acommon natural preservative in the food industry.

However, the impact of lantibiotics on the gut microbiome is not well-understood, so a team at the University of Chicago decided to research how nisin, a popular lantibiotic, affects commensal gut bacteria. This lantibiotic is naturally produced by bacteria in cows, and a similar lantibioticresides in the human gut.

During the study, researchers identified 6 specific genes in the human gut bacteria genome that produce lantibiotics akin to nisin. Researchers then assessed the effects of different versions ofgut-derived lantibiotics on pathogens and commensal gut bacteria.

The lantibiotics did not all have the same antimicrobial effects; however, they did kill both pathogens and commensal bacteria, which could have an immediate impact on gut health. The team have also been studying the peptide structures of lantibiotics to understand more about theirantimicrobial properties and have been collecting data on the prevalence of lantibiotic-resistant genes across different populations to understand how diet and other conditions inform gut colonization patterns.

“It seems that lantibiotics and lantibiotic-producing bacteria are not always good for health, so we are looking for ways to counter the potential bad influence while taking advantage of their more beneficial antimicrobial properties,” Zhang said in the article.

REFERENCES

Common food preservative has unexpected effects on the gut microbiome. University of Chicago. News Release. February 2, 2024. Accessed on February 8, 2024. https://www.eurekalert.org/news-releases/1033327