‘Safe’ Food Additive May Have Consequences for Gut Microbiome

The antimicrobial nisin used to keep foods safe from pathogens appears to be responsible for harming commensal gut microbes. 

Drazen Zigic/Shutterstock

A naturally derived antibiotic that helps preserve food by killing any threatening pathogens has kept our food safe for decades.

The World Health Organization and even watchdog groups have classified this additive, called nisin, as safe. Nisin is a lantibiotic—a peptide-derived antimicrobial agent synthesized from its natural form—first discovered in 1928 and commonly used in products such as cheese, beer, processed meats, and dipping sauces.

Nisin is made when bovine milk or whey is fermented by strains of Lactococcus lactis that are concentrated and processed into small particles. In addition to being used as a food preservative, nisin can be found in beauty products, pharmaceuticals, and pet products.

However, new research raises concern about whether nisin could be harmful to the human gut microbiome—the community of bacteria, viruses, fungi, and other microorganisms that work symbiotically to help with body functions such as digestion and immune response.

Potency of Lantibiotics

A study published in ACS Chemical Biology examined human gut bacteria genomes to identify those that resemble nisin. Researchers then produced six lantibiotics, including four new ones, and tested them on microbes. While the researchers found that these new candidates kill pathogenic bacteria, they also discovered that they have varying effects on commensal (favorable) microbes, too.

“Even though it might be very effective in preventing food contamination, it might also have a greater impact on our human gut microbes,” lead author Zhenrun “Jerry” Zhang, a postdoctoral scholar and director of the Duchossois Family Institute at the University of Chicago, said in a statement.

“This study is one of the first to show that gut commensals are susceptible to lantibiotics, and are sometimes more sensitive than pathogens. With the levels of lantibiotics currently present in food, it’s very probable that they might impact our gut health as well.”

Each person has a unique microbiome and the balance of commensal microbes is what helps the body protect itself from pathogens, create important metabolites, and more. Food additives that kill commensals could be destroying the very community that is protecting our bodies from the pathogens in food and leaving us worse off than if we’d simply eaten contaminated food, the statement pointed out.

The fact that an antimicrobial additive would kill beneficial microbes isn’t too surprising, Catherine Rall, a certified nutritionist who works with the women’s wellness company Happy V, told The Epoch Times in an email.

“This makes a certain amount of sense. Preservatives are designed to keep microbes from growing on our foods, and many of them aren’t too discriminating about which microbes they affect,” she said. ”I suspect that we’re going to find more and more preservatives with these kinds of effects as we learn more about our microbiomes.”

Slippery Slope of Bioengineering

A more sinister concern arises from the slippery slope of bioengineered food that’s becoming more commonplace, Robert Verkerk, founder and executive and science director of the nonprofit Alliance for Natural Health, told The Epoch Times.

These foods may have antimicrobial properties designed into them.

Bioengineered food is modified in a lab to alter genetic material in ways that cannot be found in nature or done by conventional breeding, according to the U.S. Department of Agriculture. In some cases, disclosure of bioengineered ingredients on food labels is discretionary.

While this new study doesn’t mention bioengineered forms of nisin, Mr. Verkerk said it’s the kind of research that lays the groundwork for the development of patented products. The Alliance for Natural Health is an international organization that promotes and protects natural, sustainable, and bio-compatible approaches to health optimization.

When a company identifies a microbe that may have a biological use, they can use technology to engineer it—sometimes drastically changing its properties—patent it, and potentially slip it into the food supply chain under the Food and Drug Administration’s “generally regarded as safe” (GRAS) umbrella, he explained.

Genetic engineering was popularized in the 2000s with the mass production of genetically modified organisms, now common in the food industry. The government has generally disregarded “little tweaks” of genome editing as long as an organism’s similar trait is being passed on, according to Mr. Verkerk.

This business model that encourages patents, biotechnology, and exclusivity often results in products that bypass thorough safety testing. And while the original intent of nisin (also known as food additive E 234) was noble—it protects us from the rare but toxic Clostridium botulinum in food—new variants may easily be slipped into food without us knowing that it’s an engineered product.

“The minute a human starts to tweak the genome or these microbes, you basically start to play God and do things that could take years to find out,” Mr. Verkerk said. ”You shouldn’t be able to get these through the front door saying these are GRAS.”

Examining Labels

Nisin does have to be listed on food ingredient labels, with the exception being processed cheese that naturally contains the nisin-producing bacteria, Mr. Verkerk said.

The additive can also be found in food packaging materials, although it doesn’t have to be declared on labeling if there’s no risk of it leaching into food.

However, he said it would be hard to determine if nisin has been bioengineered because companies can claim the product’s manufacturing is proprietary.

Bioengineered forms of nisin have been around for decades—created to “enhance the efficacy and stability of nisin under different physiologic conditions, and to enhance its pharmacokinetic properties for a variety of biological applications,” according to a 2016 article in the Journal of Applied Microbiology.

Several variants of genetically modified nisin have been identified, the article states, noting that research on the different products’ applications can be anticipated. Nisin has also been studied for use in human disease and veterinary medicine with promising results.

“The continued unearthing of new natural variants from within human and animal gastrointestinal tracts has sparked interest in the potential application of nisin to influence the microbiome, given the growing recognition of the role the gastrointestinal microbiota plays in health and disease,” reads a 2023 article in FEMS Microbiology Reviews.

While it makes sense to use a natural variation of nisin—such as those derived from the human gut microbiome—as a food additive, Mr. Verkerk pointed out that even naturally occurring biological products aren’t guaranteed to be universally effective or safe.

Because each person’s microbiome with its trillions of microbes is unique in composition, he said there’s no way to predict the response without more research.

However, he noted, it’s hard to be critical of the study, which is simply foundational research. He warned that such research is likely to lead to patented products that could be put into the market with possible harm.

“It seems to be very carefully done,” Mr. Verkerk said of the study. “It’s not close to an end product, but it’s part of a journey that would take us to an end product.”

Protecting Personal Health

In some ways, lantibiotics have escaped criticism because of their use in fermented foods—something that’s come to be associated with improved health. In nisin’s case, the bacteria is found in cow’s milk.

“It’s an easy sell in a lot of ways because everyone knows fermentation is good,” Mr. Verkerk said.

However, that doesn’t mean that the microbes being used are advantageous for human health. In some cases, they could be microbes that have not traditionally been part of the food supply—creating new preservatives foreign to human digestion that could ultimately lead to an increase in gastrointestinal issues, he said.

“The ramifications in terms of chronic disease and autoimmune disease are absolutely huge,” Mr. Verkerk said. “We’re just going to become more and more allergic and intolerant to the food we are eating.”

He recommends the following tips to help consumers protect themselves:

• Eat food you know and recognize.
• Avoid eating “bar-coded” food as much as possible.
• Try not to destroy your food in the way you cook and prepare it.
• Keep your diet as diverse and colorful as you can.

“That’s getting harder and harder for people to do,” Mr. Verkerk said.