A new study led by researchers at the Institute for Biomedical Sciences at Georgia State University revealed that emulsifiers used in food can modify the gut microbiota in mice, potentially leading to obesity and inflammatory diseases. The study was published in the journal Nature and is entitled “Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome.”
Emulsifiers, also referred to as food additives or preservatives, are ingredients added to the majority of the processed foods to enhance texture and extend shelf life of the product. These additives were found to alter the gut microbiota composition, which refers to the microbe community present in the intestinal tract, known to be important for the body’s metabolism and immune development. Researchers found that disturbances of the gut microbiota can result in intestinal inflammation that potentially lead to the development of inflammatory bowel disease (like ulcerative colitis and Crohn’s disease) and metabolic syndrome (obesity-associated disorder linked to hyperglycemia and insulin resistance).
“The dramatic increase in these diseases has occurred despite consistent human genetics, suggesting a pivotal role for an environmental factor,” said the study’s lead author Dr. Benoit Chassaing in a news 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.”
In order to test the hypothesis that emulsifiers have an impact on gut microbiota, researchers fed mice models with two common emulsifiers often used in food – carboxymethylcellulose and polysorbate 80 – at doses similar to the ones found in almost all processed foods. The team found that consumption of emulsifiers indeed led to an alteration in the bacterial species composing the gut microbiota, resulting in a microbiota with increased pro-inflammatory potential. Emulsifiers were found to promote metabolic syndrome and mild intestinal inflammation in normal mice, while they have no effect on germ-free mice, which do not have a microbiota. Interestingly, microbiota transplanted from emulsifier-treated mice into germ-free mice induced some features of low-grade inflammation and metabolic syndrome.
“We do not disagree with the commonly held assumption that over-eating is a central cause of obesity and metabolic syndrome,” said the study’s senior author Dr. Andrew T. Gewirtz. “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.”
The team believes that the broad use of emulsifiers might be contributing to the epidemic of obesity/metabolic syndrome in society and to the development of several chronic gut inflammatory diseases. This is the first time that food additives have been shown to directly have an impact on health, and based on their findings, the research team suggests that the current methods for testing and approving food additives might not be adequate. The next goal of the team is to analyze other emulsifiers and investigate their impact in human microbiota and how they affect body metabolism.