Some common artificial sweeteners can make healthy gut bacteria turn against us, new research has found.
All it takes is enough sweetener found in just two cans of artificially sweetened drink.
"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," said lead author Havovi Chichger, a senior lecturer in biomedical science at Anglia Ruskin University in the UK.
"These pathogenic changes include greater formation of biofilms and increased adhesion and invasion of bacteria into human gut cells."
In the study, sucralose and aspartame caused the bacteria in our guts to attach to and kill cells which line the intestinal wall, allowing some - such as E. faecalis - to "congregate in the lymph nodes, liver, and spleen, causing a number of infections including septicaemia".
All three sweeteners can stick to each other creating a "biofilm", making them "less sensitive to antimicrobial resistance treatment and are more likely to secrete toxins".
"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," said Dr Chichger.
Sweeteners are used in place of sugar. They are much sweeter than sugar, meaning less is needed - resulting in fewer calories being consumed.
There have been some prior studies which found consuming sweeteners might actually result in people eating more calories - the mismatch between sweetness and calories confuses the body, making people hungry for more. They can also make food taste nicer, encouraging more consumption.
"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."
The study was published in the International Journal of Molecular Sciences.