Sauerkraut and gut bacteria in a 4-week trial
What it found
In 87 healthy adults, eating fresh or pasteurized sauerkraut daily for 4 weeks changed some single gut bacterial species but not overall bacterial diversity.
Only the pasteurized sauerkraut raised short-chain fatty acids in blood.
What they found
Studies in people
Overall gut bacteria
Neither fresh nor pasteurized sauerkraut changed overall bacterial diversity or the broad bacterial community in the gut. The authors say the gut microbiome of healthy people is rather resilient to short-term dietary changes.
Single bacterial species
Some individual bacterial species did change. After fresh sauerkraut, a Lactobacillus species from the sauerkraut itself increased in stool. After pasteurized sauerkraut, Anaerostipes hadrus increased and Blautia obeum decreased.
Short-chain fatty acids
Only pasteurized sauerkraut increased short-chain fatty acids (acetic, propionic and butyric acid) in blood serum. Fresh sauerkraut decreased butyric acid in stool.
Digestive tolerance
Both sauerkrauts were well tolerated. There was no significant change in stool form, how often people went to the toilet, or stool pH.
Animal and lab studies
Bacteria in sauerkraut
The fresh sauerkraut was dominated by Lacticaseibacillus paracasei, but after 7 weeks of cold storage Limosilactobacillus reuteri became dominant. The pasteurized sauerkraut contained no living bacteria and little bacterial DNA.
What the authors conclude
“We conclude that fresh and pasteurized sauerkraut had no overall impact on the gut microbiota of healthy participants, even though single species changed significantly in relative abundance.”
Also in their conclusions
- They conclude that fresh and pasteurized sauerkraut had no overall impact on the gut microbiota of healthy participants, even though single species changed significantly in relative abundance.
- They say the significant increase in serum short-chain fatty acid levels during the pasteurized sauerkraut intervention might link sauerkraut consumption with a potential impact on systemic health.
- They advise that the specific composition of the sauerkraut might be an important determinant of the gut microbiota-host interaction.
How it was done
Sauerkraut is a fermented food that has been suspected to benefit the gut microbiome, but scientific evidence is sparse. The authors wanted to test whether fresh and pasteurized sauerkraut shift gut microbial composition and short-chain fatty acid levels in healthy people.
They ran a randomized crossover trial with 87 healthy men and women, aged 21 to 69. Each person ate 100 g of fresh or pasteurized sauerkraut daily for 4 weeks, with 4-week washout periods before each phase. Stool and blood samples were collected at five time points.
What it can’t tell you
- The study lasted only 4 weeks, so it cannot show what would happen with longer-term sauerkraut consumption.
- The authors could not reliably identify the bacteria or their components in the pasteurized sauerkraut, so they cannot say exactly what caused the changes seen.
- The participants were healthy adults who liked sauerkraut and were interested in healthy eating, so the results may not apply to other groups.
Who paid
- Conflicts
- Declarations. Ethics approval and consent to participate: The University of Freiburg’s ethical review committee approved the project. All participants provided written informed consent before any data or samples were collected. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.
- Authors work at
- University of Freiburg, Germany; Helmholtz Centre for Infection Research, Germany; Center for Individualized Infection Medicine (CiiM), Germany
The paper
- Title
- The impact of regular sauerkraut consumption on the human gut microbiota: a crossover intervention trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Schropp N, Bauer A, Stanislas V, et al (2025). The impact of regular sauerkraut consumption on the human gut microbiota: a crossover intervention trial. Microbiome. doi:10.1186/s40168-024-02016-3Free full textPubMed 39940045DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error