How gut bacteria break down steviol glycosides in the intestine
What it found
Gut bacteria break down steviol glycosides into a single substance called steviol, which is then taken up from the intestine.
This happens in both people and animals.
What they found
Animal and lab studies
Speed of breakdown differs
In lab tests, gut bacteria broke down stevioside faster than they broke down rebaudioside A.
No epoxide formed
Recent lab tests using mass spectrometry showed that a compound called steviol-16,17-epoxide is not made when gut bacteria break down these sweeteners.
Studies in people and animals
Broken down by gut bacteria
Steviol glycosides are not taken up whole by the body. Gut bacteria break them down into a single substance called steviol, which is then absorbed from the intestine.
Rats match people closely
Lab tests mixing gut bacteria from people gave similar results to tests using animal gut bacteria. The authors say this makes rats a suitable model for studying these sweeteners.
Other findings
Bacteria responsible for breakdown
A group of bacteria called Bacteroides does most of the work. They use an enzyme activity to split the sweetener molecules apart.
What the authors conclude
- They note that because both sweeteners are broken down the same way into steviol, safety data on stevioside applies to rebaudioside A too.
- They conclude that rats are a suitable model for studying how these sweeteners are processed by gut bacteria.
How it was done
Scientists wanted to understand how gut bacteria handle two common sweeteners, stevioside and rebaudioside A. They also looked at whether animal tests give results that match what happens in people.
The authors gathered and examined existing research on how gut bacteria process these sweeteners. They looked at lab tests using mixed gut bacteria from both people and animals. They also checked newer studies that used mass spectrometry to identify breakdown products.
What it can’t tell you
- We summarised it from the abstract only.
- Lab tests using gut bacteria outside the body may not perfectly match what happens inside a living person.
- Because both sweeteners form the same breakdown product, this work cannot show if they differ in other ways once inside the body.
Who paid
- Authors work at
- University of Southampton, UK
The paper
- Title
- Microbial hydrolysis of steviol glycosides
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Abstract only
- Cite
- Renwick AG, Tarka SM (2008). Microbial hydrolysis of steviol glycosides. Food and chemical toxicology. doi:10.1016/j.fct.2008.05.008PubMed 18550247DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error