Erythritol and gut bacteria in lab tests
What it found
In lab tests with human gut bacteria, erythritol was not broken down over 24 hours.
The authors say it is very unlikely to be fermented in the body.
What they found
Animal and lab studies
No breakdown
Erythritol was completely resistant to attack by gut bacteria over 24 hours. No adaptation happened in that time.
No gas made
Almost no extra gas was produced from erythritol compared to the blank sample. No hydrogen built up either.
Acids and pH
Erythritol and the blank sample did not differ in acid production or pH change. Maltitol and lactulose did produce acids and lower the pH.
Maltitol comparison
Maltitol broke down completely within 24 hours, though more slowly than lactulose at first. It made more propionate and butyrate than lactulose.
Other findings
Energy from fermentation
The authors say the contribution to daily energy intake from gut fermentation of erythritol after swallowing is considered to be nil.
What the authors conclude
“Taking all fermentation parameters into account, erythritol turned out to be completely resistant to bacterial attack within 24 h, thus excluding an adaptation within that period.”
Also in their conclusions
- They state that erythritol as a sole substrate is completely non-fermentable by freshly collected human faecal microbiota within a period of 24 h.
- They say that although its total resistance to faecal bacterial fermentation in vivo is not definitively proven, it seems very likely that erythritol is excreted unchanged in man.
- They note that a complete balance study would be required for verification in vivo.
How it was done
The authors wanted to check whether gut bacteria can adapt their enzymes to break down erythritol over a longer period, since earlier tests only lasted 12 hours.
They mixed erythritol with fresh gut bacteria from human stool samples and watched it for 24 hours. They compared it with maltitol, lactulose and a sample with no added sugar.
What it can’t tell you
- This was a lab test using gut bacteria from stool samples, not a study in living people.
- The authors say a complete balance study in people would be needed to confirm what happens in the body.
Who paid
- Authors work at
- Swiss Federal Institute of Technology (ETH), Switzerland
The paper
- Title
- Human gut microbiota does not ferment erythritol
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Cite
- Arrigoni E, Brouns F, Amadò R (2005). Human gut microbiota does not ferment erythritol. The British journal of nutrition. doi:10.1079/bjn20051546Free full textPubMed 16277764DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error