A sweetener used in cakes, soft drinks and chewing gum can seriously damage people’s health by weakening the gut, a new study has found.

Consumption of even a small amount of the sweetener neotame can lead to someone starting to suffer irritable bowel syndrome, insulin resistance, and even sepsis, a condition that kills about 40,000 in Britain a year.

The findings underlined that some of a new generation of sweeteners that give food products a super-sweet taste can have a “toxic effect” on health, the researchers said.

Dr Havovi Chichger , the senior author of the study, said that while sweeteners could be a healthier alternative to sugar, some could harm consumers.

Neotame was developed in 2002 as a substitute for aspartame, a sweetener which has aroused concerns, and has become widely used in recent years in drinks and foodstuffs sold in the UK. It is often referred to as E961 on the list of ingredients found on labels of products.

Chichger, an associate professor at Anglia Ruskin University, and the study’s co-author, Dr Aparna Shil, of Jahangirnagar University, in Bangladesh, said neotame carried a threat to health because it could damage the intestine by causing “good bacteria” to become diseased and invade the gut wall. In the process that could lead to illness because the epithelial barrier, part of the gut wall, could break down.

They published their findings, which they said are the first to show that neotame can have that damaging impact on healthy gut bacteria, in the medical journal Frontiers in Nutrition.

Previous research, including by Chichger, found that other common sweeteners – such as saccharin, sucralose, and aspartame – can also have that harmful effect.

Chichger said: “There is now growing awareness of the health impacts of sweeteners such as saccharin, sucralose and aspartame, with our own previous work demonstrating the problems they can cause to the wall of the intestine and the damage to the ‘good bacteria’ which form in our gut.

“This can lead to a range of potential health issues including diarrhoea, intestinal inflammation, and even infections such as septicaemia if the bacteria were to enter the blood stream. Therefore, it is important to also study sweeteners that have been introduced more recently, and our new research demonstrates that neotame causes similar problems, including gut bacteria becoming diseased.”

The co-authors said further research was needed to look into “the toxic effects of some of the artificial sweeteners that have been developed more recently”, given their widespread use. Some of the newest sweeteners in use produce a sweet taste that is 1,000 times sweeter than sugar.

Even a low intake of neotame might be harmful, Chichger stressed. “Even when we studied neotame at very low concentrations, 10 times lower than the acceptable daily intake, we saw the breakdown of the gut barrier and a shift in bacteria to a more damaging behaviour, including increased invasion of healthy gut cells leading to cell death. This can be linked to issues such as irritable bowel diseases and sepsis,” she said.

The European Food Safety Authority ruled in 2007 that neotame was “safe for use”. It has since been approved for use in more than 35 countries. But Efsa is now reviewing the safety of neotame as part of what Chichger said is a series of evidence-based risk assessments which may lead to a reassessment of certain sweeteners.

• This article was amended on 26 April 2024. The European Food Safety Authority’s evaluation of neotame was in 2007, not in 2010.