Common sweeteners ‘can cause gut bacteria to invade intestines’, Anglia Ruskin University research finds

Common artificial sweeteners can cause gut bacteria to become diseased and invade the gut wall, potentially leading to serious health issues, molecular research has found.

The work, led by Anglia Ruskin University scientists, is the first to show the pathogenic effects of some of the most widely used artificial sweeteners – saccharin, sucralose, and aspartame – on two types of gut bacteria, E. coli (Escherichia coli) and E. faecalis (Enterococcus faecalis).

It shows that these pathogenic bacteria can attach themselves to, invade and kill epithelial cells that line the wall of the intestine, called Caco-2 cells.

It is known that bacteria such as E. faecalis that cross the intestinal wall can enter the bloodstream and congregate in the lymph nodes, liver and spleen, which can lead to a number of infections including septicaemia.

The researchers found that in a concentration equivalent to two cans of diet soft drink, all three artificial sweeteners significantly increased the adhesion of both E. coli and E. faecalis to intestinal Caco-2 cells, and differentially increased the formation of biofilms.

Bacteria growing in biofilms are less sensitive to treatments for antimicrobial resistance and are more likely to secrete toxins and express virulence factors, which can cause disease.

The scientists found the sweeteners caused the pathogenic gut bacteria to invade Caco-2 cells - although saccharin had no significant effect on E. coli invasion.

Earlier studies had shown that artificial sweeteners can change the number and type of bacteria in the gut.

Senior author of the paper Dr Havovi Chichger, senior lecturer in biomedical science at ARU, said: “There is a lot of concern about the consumption of artificial sweeteners, with some studies showing that sweeteners can affect the layer of bacteria which support the gut, known as the gut microbiota.

“Our study is the first to show that some of the sweeteners most commonly found in food and drink – saccharin, sucralose and aspartame – can make normal and ‘healthy’ gut bacteria become pathogenic.

“These pathogenic changes include greater formation of biofilms and increased adhesion and invasion of bacteria into human gut cells.

“These changes could lead to our own gut bacteria invading and causing damage to our intestine, which can be linked to infection, sepsis and multiple-organ failure.

“We know that overconsumption of sugar is a major factor in the development of conditions such as obesity and diabetes. Therefore, it is important that we increase our knowledge of sweeteners versus sugars in the diet to better understand the impact on our health.”

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