Emulsifiers, which are added to most processed foods to aid texture and extend shelf life, can alter the gut microbiota composition and localization to induce intestinal inflammation that promotes the development of inflammatory bowel disease and metabolic syndrome, new research shows.
The research, published February 25 in Nature, was led by Georgia State University Institute for Biomedical Sciences' researchers Benoit Chassaing, PhD, and Andrew T. Gewirtz, PhD, and included contributions from Emory University, Cornell University, and Bar-Ilan University, in Israel.
Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, afflicts millions of people and is often severe and debilitating. Metabolic syndrome is a group of very common obesity-related disorders that can lead to type-2 diabetes, cardiovascular, and/or liver diseases. Incidence of IBD and metabolic syndrome has been markedly increasing since the mid-20th century.
The term "gut microbiota" refers to the diverse population of 100 trillion bacteria that inhabit the intestinal tract. Gut microbiota are disturbed in IBD and metabolic syndrome. Chassaing and Gewirtz's findings suggest emulsifiers might be partially responsible for this disturbance and the increased incidence of these diseases.
"A key feature of these modern plagues is alteration of the gut microbiota in a manner that promotes inflammation," Gewirtz says.
"The dramatic increase in these diseases has occurred despite consistent human genetics, suggesting a pivotal role for an environmental factor," according to Chassaing. "Food interacts intimately with the microbiota so we considered what modern additions to the food supply might possibly make gut bacteria more proinflammatory."
Addition of emulsifiers to food seemed to fit the time frame and had been shown to promote bacterial translocation across epithelial cells. Chassaing and Gewirtz hypothesized that emulsifiers might affect the gut microbiota to promote these inflammatory diseases and designed experiments in mice to test this possibility.
The team is now testing additional emulsifiers and designing experiments to investigate how emulsifiers affect humans. If similar results are obtained, it would indicate a role for this class of food additive in driving the epidemic of obesity, its interrelated consequences and a range of diseases associated with chronic gut inflammation.
While detailed mechanisms underlying the effect of emulsifiers on metabolism remain under study, the team points out that avoiding excess food consumption is of paramount importance.
"We do not disagree with the commonly held assumption that overeating is a central cause of obesity and metabolic syndrome," Gewirtz says. "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 notes that the results of their study suggest that current means of testing and approving food additives may not be adequate to prevent use of chemicals that promote diseases driven by low-grade inflammation and/or which will cause disease primarily in susceptible hosts.
[Source: Georgia State University]