Emulsifiers, which are added to most processed foods to aid texture and extend shelf life, can induce intestinal inflammation, say a new research.
The additives alter the gut microbiota composition that promotes the development of inflammatory bowel disease and metabolic syndrome. Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, afflicts millions of people and is often severe and debilitating.
"A key feature of these modern plagues is alteration of the gut microbiota in a manner that promotes inflammation," said lead researcher Andrew T. Gewirtz of Georgia State University.
"Food interacts intimately with the microbiota so we considered what modern additions to the food supply might possibly make gut bacteria more pro-inflammatory," said the researcher.
Metabolic syndrome is a group of very common obesity-related disorders that can lead to type-2 diabetes, cardiovascular and/or liver diseases.
The team fed mice two very commonly used emulsifiers, polysorbate 80 and carboxymethylcellulose, that are added to almost all processed foods.
They observed that emulsifier consumption changed the species composition of the gut microbiota and did so in a manner that made it more pro-inflammatory.
The altered microbiota had enhanced capacity to digest and infiltrate the dense mucus layer that lines the intestine.
Alterations in bacterial species resulted in bacteria expressing more flagellin and lipopolysaccharide, which can activate pro-inflammatory gene expression by the immune system.
"We do not disagree with the commonly held assumption that over-eating is a central cause of obesity and metabolic syndrome," Gewirtz said.
The researchers noted 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.
The study was published in Nature.
