Ice cream lovers, look away now. Studies on a simulated human gutĀ have added further evidence that emulsifiers, found in most processed foods, might be linked to obesity, diabetes and inflammatory bowel disorders.
Emulsifiers are used to improve a foodās texture and to prevent mixtures from separating, particularly in ice cream. Last year, Benoit Chassaing of Georgia State University showed that mice that drank water containing one of two emulsifiers underwent changes in gut bacteria and inflammation of the gutĀ ā changes that led to obesity and diabetes in these animals.
However, mice that didnāt haveĀ any gut bacteria because they had been raised in a sterile environment didnāt become ill when given the same additives, suggesting that it is the emulsifiersā effect on the microbiome that is to blame. When the ill mice stopped consuming emulsifiers, their gutĀ bacteria gradually returned toĀ normal.
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The question is whether the same might be true for humans. The growing use of emulsifiers has coincided with a rise in obesity and diabetes, says Chassaing, while these conditions arenāt as common in countries where less processed food is consumed.
Now Chassaing has supported his findings in mice using a simulation of the human gut. Working with a team in Belgium, he looked at two emulsifiers: carboxymethylcellulose (E566 on EU labels) and polysorbate-80 (E433). When added to a series of flasks that mimic the conditions of the human digestive tract, each caused an increase in the levels of a bacterial protein called flagellin, known to cause inflammation at high concentrations. Chassaing presented the results at a at the Royal Society inĀ London.
āThe growing use of emulsifiers has coincided with a rise in obesity and diabetesā
The simulator results are more convincing than the mouse studies, since lab animals and humans have vastly different gut microbiomes, says of the University of Reading in the UK, who studies gut disorders. āThe definitive test, however, isĀ obviously a human trial.ā
Chassaing is now enrolling volunteers for the first human trial to look at the effects of emulsifiers on gut and metabolic health. Carrying out this study wonāt be easy, he says, as the participantsā diets will have toĀ beĀ strictly controlled.
In his earlier work, the mice were given up to 1 per cent of an emulsifier in their water, which Chassaing thinks reflects the levels some people may be consuming. But ofĀ the Louvain Drug Research Institute in Belgium thinks people who eat a balanced diet are unlikely to be exposed to the levels given to the mice.
Nevertheless, Cani says, we should be concerned. Whatever the results of the human trial, regulators need to rethink the wayĀ they test the safety of food, heĀ says, as existing tests were developed before we understood the importance of our gut microbiota and how they can be affected by what we consume.
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