How gut bacteria break down steviol glycosides
What it found
Steviol glycosides are not taken in whole.
Gut bacteria split them into steviol, which is then absorbed from the gut.
What they found
Studies in people and animals
Human and animal flora alike
Lab tests with mixed gut bacteria from people and from animals gave similar results. This suggests the rat is a suitable model for studies on steviol glycosides.
Other findings
Broken down in the gut
Stevioside and rebaudioside A are not absorbed intact. Gut bacteria break them down into steviol.
Steviol is absorbed
Steviol is not broken down further by gut bacteria. It is absorbed from the intestine.
Stevioside breaks down faster
Stevioside is broken down faster than rebaudioside A.
No epoxide metabolite
Recent studies using mass spectrometry found that steviol-16,17-epoxide is not made by gut bacteria from steviol glycosides.
Which bacteria do it
Bacteroides species do most of the breakdown, using their beta-glucosidase activity.
What the authors conclude
“Given the similarity in the microbial metabolism of stevioside and rebaudioside A with the formation of steviol as the single hydrolysis product that is absorbed from the intestinal tract, the toxicological data on stevioside are relevant to the risk assessment of rebaudioside A.”
Also in their conclusions
- They say that because stevioside and rebaudioside A are broken down in the same way, with steviol as the single product absorbed from the gut, the toxicological data on stevioside are relevant to the risk assessment of rebaudioside A.
How it was done
The authors wanted to understand the role of gut bacteria in how the body handles stevioside and rebaudioside A.
What it can’t tell you
- We summarised it from the abstract only.
- This work looks at how gut bacteria break these sweeteners down, not at health effects in people.
- The comparison between human and animal gut bacteria comes from lab tests, so it cannot show what happens inside a living person.
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 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error