Skip to content

An earlier post discussed how emulsifiers (which are added to most processed foods to aid texture and extend shelf life) can alter the the community of microbes that live in our gut (gut microbiota) in such a way as to cause intestinal inflammation. Now the same researchers found that regular consumption of emulsifiers alter intestinal bacteria in a manner that promotes low-grade intestinal inflammation and possibly colorectal cancer.

The emulsifiers used in the study were the commonly used carboxymethylcellulose and polysorbate-80, but some others are soy lecithin, carrageenan, and polyglycerol ester. Processed foods often contain several emulsifiers, and while food regulations limit the amount of each emulsifier present in a particular food product to 1% to 2%, they don’t restrict the number of emulsifiers allowed. The study was done in mice, but the researchers tried to model the level of exposure of humans who eat a lot of processed food. From Science Daily:

Common food additive promotes colon cancer in mice

Emulsifiers, which are added to most processed foods to aid texture and extend shelf life, can alter intestinal bacteria in a manner that promotes intestinal inflammation and colorectal cancer, according to a new study. The findings, published in the journal Cancer Research, show regular consumption of dietary emulsifiers in mice exacerbated tumor development....There is increasing awareness that the intestinal microbiota, the vast, diverse population of microorganisms that inhabits the human intestines, play a role in driving colorectal cancer.

The microbiota is also a key factor in driving Crohn's disease and ulcerative colitis, the two most common forms of inflammatory bowel disease (IBD). IBD is known to promote colon tumorigenesis and gave rise to the term "colitis-associated cancer." Low-grade inflammation, a condition more prevalent than IBD, was shown to be associated with altered gut microbiota composition and metabolic disease and is observed in many cases of colorectal cancer. These recent findings suggest dietary emulsifiers might be partially responsible for this association.

Previous reports by the Georgia State research team suggested that low-grade inflammation in the intestine is promoted by consumption of dietary emulsifiers, which are detergent-like molecules incorporated into most processed foods that alter the composition of gut microbiota. The addition of emulsifiers to food seems to fit the time frame and had been shown to promote bacterial translocation across epithelial cells. Viennois and Chassaing hypothesized that emulsifiers might affect the gut microbiota in a way that promotes colorectal cancer. They designed experiments in mice to test this possibility.

In this study, the team fed mice with two very commonly used emulsifiers, polysorbate 80 and carboxymethylcellulose, at doses seeking to model the broad consumption of the numerous emulsifiers that are incorporated into the majority of processed foods. Researchers observed that consuming emulsifiers drastically changed the species composition of the gut microbiota in a manner that made it more pro-inflammatory, creating a niche favoring cancer induction and development. Alterations in bacterial species resulted in bacteria expressing more flagellin and lipopolysaccharide, which activate pro-inflammatory gene expression by the immune system.

This research suggests that emulsifiers (which are added to most processed foods to aid texture and extend shelf life) can alter the gut microbiota (the community of microbes that live in our gut) in such a way as to cause intestinal inflammation. Even though the study was done on mice, it is thought it also applies to humans. From Medical Daily:

You Are What You Eat: Food Additive Emulsifier Inflames Mouse Gut And Causes Obesity

Processed foods have changed the way we eat. Food can sit longer on shelves, but what does that mean for the stomach? In a new study published in the journal Nature, researchers from Georgia State University investigated how the widely used processed food additive emulsifiers played a role in the gut.

Emulsifiers are added to most processed foods in order to extend shelf life and add texture to the foods. The research team decided to feed mice a couple of the most common emulsifiers on the market — polysorbate 80 and carboxymethylcelluloseat doses comparable to a human’s consumption of processed foods. They watched the emulsifier change the mice’s gut microbiota, which is an individual’s personal 100 trillion bacteria inside the intestinal tract. Not only did this increase their chance of developing obesity-related disorders, but also inflammatory bowel disease. It’s no coincidence both conditions have been increasing since the 1950s.

"The dramatic increase in these diseases has occurred despite consistent human genetics, suggesting a pivotal role for an environmental factor," the study’s coauthor Benoit Chassaing, a researcher from GSU’s Institute for Biomedical Sciences, said in a press release. "Food interacts intimately with the microbiota, so we considered what modern additions to the food supply might possibly make gut bacteria more pro-inflammatory."

The emulsifiers, which are groups of oil-and water-friendly molecules, help to hold food together. Mayonnaise without emulsifiers, for example, will separate from an oily top layer to a thicker white layer that rests on the bottom of the jar. Once the emulsifiers were digested by the mice, their blood-glucose levels went awry, inflamed their intestinal mucus layer, which left them with weight gain, specifically concentrated in the abdomen. The bacterial changed triggered chronic colitis from causing intestinal inflammation and metabolic syndrome, which includes obesity, hyperglycemia, and insulin resistance.

Ultimately, microbiologists say you are what you eat. If your diet is smeared with margarine, mayonnaise, creamy sauces, candy, ice cream, and most other packaged and processed baked goods, you and your gut may be at risk. "We do not disagree with the commonly held assumption that over-eating is a central cause of obesity and metabolic syndrome," the study’s coauthor Andrew T. Gewirtz, a researcher from GSU’s Institute for Biomedical Sciences, said in a press release. "Rather, our findings reinforce the concept suggested by earlier work that low-grade inflammation resulting from an altered microbiota can be an underlying cause of excess eating."