Artificial sweeteners may alter gut bacteria and glucose metabolism, study finds

A new human study has identified potential changes linked to the consumption of certain artificial sweeteners, with results suggesting they may impact the balance of gut bacteria and the way the body processes glucose, according to the British newspaper The Mirror.

The research was conducted by scientists from the Elinav Lab at the Weizmann Institute, involving 120 participants who had not previously consumed foods or drinks containing artificial sweeteners before the trial began.

Participants were divided into six groups. Four groups received one of four sweeteners—saccharin, sucralose, aspartame, or stevia—while the remaining two groups did not receive any sweeteners.

After two weeks, researchers observed changes in the composition and function of the participants' gut microbiome, the community of microorganisms living in the intestines that play multiple roles in bodily functions.

The nature of these changes varied, depending on the type of sweetener and individual responses among participants.

Results showed that saccharin and sucralose were associated with notable changes in the body's ability to process and metabolize glucose. The researchers noted these changes warrant further investigation, given that impaired glucose metabolism is linked to conditions such as type 2 diabetes and obesity.

However, the researchers emphasized that the findings do not necessarily reveal the long-term health effects of these changes, stressing the need for longer studies to determine the impact of sweeteners on health.

They also clarified that the results do not suggest sugar is a healthier alternative to artificial sweeteners, but rather highlight the need for more research to understand the effects of different sweetener types on the human body.

What do health authorities say?

The UK’s National Health Service (NHS) states that approved sweeteners undergo safety assessments before being permitted for use and are considered an acceptable alternative to sugar when used within recommended limits.

The NHS notes that scientific evidence on the effects of sweeteners on health and weight remains mixed. Some short-term studies have found that replacing sugary drinks with low- or no-calorie sweetened alternatives can help reduce calorie intake and limit weight gain, while longer-term studies have produced varied results.

Johns Hopkins University School of Medicine also notes that research into the potential health effects of sweeteners is ongoing, and that human studies generally indicate they are safe when consumed within accepted daily limits.

As for sugar, the school does not consider it inherently harmful, as the body relies on glucose for energy. However, excessive intake of added sugar—found in large amounts in many processed foods and drinks—may be linked to elevated blood sugar, insulin resistance, obesity, tooth decay, and increased risk of type 2 diabetes.

In light of these findings, the study suggests that some sweeteners may cause short-term changes in the gut microbiome and the body’s glucose response, but determining whether these changes have long-term health effects will require further research and longer follow-up.