The ingredients that give a stable smooth ice cream, chocolate bars and other packaged snacks can promote certain inflammatory diseases chronic. This is the claim of a new study, which finds increasing metabolic diseases and intestinal inflammation in mice fed two emulsifiers commonly used in processed foods. The authors are far from confirming the similar effects in humans, but they suggest that these ingredients cause damage by disrupting the barrier between the immune system and the microbiome-the collection of microbes that inhabit our bodies.
The finding, published online today in Nature is "credible and remarkable," says Karen Madsen, a microbiologist at the University of Alberta in Edmonton, Canada, who was not involved in the study. "It sends a clear message that the changes in our food supply are altering our microbiota and our health."
Gut microbes help us fight infection and resist to allergies, but there is one thing we do not want them to do. touch our intestinal mucosa "These trillion bugs have sort of got to be kept away from us," said Madsen. Normally, mucus layer separates the intestinal cells of the intestine bacteria. But if these bacteria reach the cells, they can stimulate the immune system and cause inflammation. This inflammation of the digestive tract out-of-control is the hallmark of the inflammatory bowel disease (IBD), which causes diarrhea, fatigue and abdominal pain. Chronic inflammation has also been associated with metabolic-a set of concomitant requirements syndrome, including obesity and high blood pressure, that increase the risk of heart disease and diabetes from one person.
Benoit Chassaing, a microbiologist at Georgia State University in Atlanta, wonders if such bacterial invasion could explain what he described as a "perfect correlation" between the increasing use of food additives in industrialized countries and the incidence of IBD. (The disease affects more than one million people in the United States and appears to be rising.) The work by other groups led Chassaing and his colleagues to focus on emulsifiers detergentlike-Coax compounds in a surface smooth, creamy mixture of the ingredients that might otherwise prefer to separate, as the milk fat and water in the ice cream. A 09 study found that carboxymethylcellulose emulsifier supply (CMC) in genetically engineered mice that were already predisposed to intestinal inflammation has led to excessive growth of bacteria in their small intestines and increased inflammation.
In the new work, researchers fed two common emulsifiers, CMC and polysorbate 80, both a strain of genetically susceptible mice and type mice wild-without genetic mutations that put them at increased risk of IBD or metabolic syndrome. Among the sensitive mouse, eat or drink emulsifiers for 12 weeks increased the risk of developing symptoms of colitis mouse model of intestinal inflammation seen in humans with IBD - 40 to 80% %. wild type mice do not develop colitis, but showed a low-grade inflammation in their intestines and several features of the metabolic syndrome: slight weight gain, increased body fat and food intake, and higher levels of blood sugar, which indicates poor regulation of glucose associated with diabetes.
How emulsifiers induce these changes is still uncertain, but the study offers some advice. microscopic imaging of the intestines has shown that the average distance between intestinal bacteria and intestinal cells was reduced by more than half; bacteria seemed to move toward the intestinal mucosa. And fed emulsifier mouse feces showed a greater number of bacteria known to digest and penetrate the mucus. The feces contain a microbiome also seemed more "pro-inflammatory", meaning more highly activated receptors bacteria that trigger inflammation but it is not yet clear that bacteria have that effect. The conclusion of Chassaing: Either emulsifiers damage the mucus layer directly, leaving vulnerable to bacteria, or change the composition of the microbiota, favoring mucus microbes penetrating
This is not at all surprising that these substances have a . effect on intestinal microbes, said Mia Phillipson, a physiologist at the University of Uppsala in Sweden, which studies the interactions of gut inflammation and mucus bacteria. All to be vegetarian to be born by Caesarean section may change the composition of our microbiome significantly, she notes. But relatively few studies to date have examined the effect of food additives on the microbiome in this level of detail. "I think we're just about to realize how important this is," she said. Regarding the implications in humans, Phillipson said it is too early to make general recommendations, but it suggests that people with IBD or a family history of the disease consider avoid these ingredients.
Chassaing, too, is careful not to throw these emulsifiers as the ultimate villain. "Of course, society has changed so dramatically in the last century ... and so many other factors were used in the foods that we can not really even know that the most important role we play." His group is preparing a more ambitious study comparing microbiomes of people who avoid completely emulsifiers for several weeks with those on a standard Western diet.
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