Ever wondered about why the mayonnaise you bought at the market is so smooth and creamy, rather than a mixture of water and oily globules as it should be? How about ice cream or say, milk- Nature’s own product which consists of a complex mixture of fat droplets suspended in a solution. Yes, you are right! The consistency we see in most foods, is due to the presence of emulsifiers which mixes oil and water and makes stable emulsions. Nature uses proteins and phospholipids to cause emulsions, hence food industry contains a variety of emulsifiers modelled on these natural substances.
In a recent study published in the prestigious journal Nature, a group of researchers from Georgia State University Institute for Biomedical Sciences have shown that these emulsifiers can alter the gut microbiota composition and localization, thereby inducing intestinal inflammation which in turn promotes the development of inflammatory bowel disease like Crohn’s disease and metabolic syndrome.
Inflammatory bowel disease (IBD), which includes Crohn’s disease and ulcerative colitis, affects millions of people and is often severe. Gut microbiota refers to the 100 trillion bacteria which resides in the intestinal tract and helps our body in the absorption of nutrients, production of vitamins and immunity. These diseases affect the gut microbiota and this research finding suggests that emulsifiers could be partially responsible for this disturbance and the increased incidence of these diseases.
“The dramatic increase in these diseases has occurred despite consistent human genetics, suggesting a pivotal role for an environmental factor,” says lead author Benoit Chassaing. “Food interacts intimately with the microbiota so we considered what modern additions to the food supply might possibly make gut bacteria more pro-inflammatory.”
They tested two commonly used emulsifiers such as polysorbate 80 and carboxymethylcellulose in mice, at doses which are reflective of the amount present in most processed foods.
They found that emulsifiers changed the species composition of gut microbiota and made it more pro-inflammatory. The altered microbiota had enhanced capacity to digest and infiltrate the thick mucus layer lining the intestine, which normally lacks bacteria. Due to the alteration in bacterial species, it resulted in more bacteria expressing flagellin and lipopolysaccharide, which triggered inflammation and activated the immune system.
In mice, which were genetically engineered to be susceptible to colitis- the altered bacterial profile caused the immune system to wreak havoc and caused chronic colitis. In mice with normal immune systems, emulsifiers induced mild intestinal inflammation which disturbed their microbiome. This made the normal mice eat more, which made them fatter and lead to metabolic syndrome.
None of these effects were seen in germ-free mice, indicating that the emulsifiers achieved them through their influence on the microbiome.
The team is now studying other emulsifiers and their effects on human beings. Even as the role of emulsifiers in metabolism and metabolic syndrome is being studied further, scientists warn against the tendency of excess food consumption.
“We do not disagree with the commonly held assumption that over-eating is a central cause of obesity and metabolic syndrome,” Andrew T. 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.”
Thus, emulsifiers may have contributed to the enormous increase in inflammatory bowel disease and metabolic syndrome that has occurred over the last half century. So, maybe we are not binge eaters after all. The altered microbiome caused by the emulsifiers is making us do it!
Source: Georgia State university
The original publication can be accessed here.