Maltodextrin and gut bacteria in a probiotic trial
What it found
In 33 healthy adults, maltodextrin taken as a placebo increased some Bifidobacterium bacteria in the gut.
The effect varied depending on each person's starting gut bacteria type.
What they found
Studies in people
Bifidogenic effect of maltodextrin
Maltodextrin, used as the placebo, increased some Bifidobacterium species in the gut. This effect was seen in two of the three groups of people, based on their starting gut bacteria.
Three gut bacteria types
At the start, the 33 people fell into three groups based on their gut bacteria. Each group responded differently to the probiotic and maltodextrin treatments.
Probiotic bacteria detected
Lacticaseibacillus rhamnosus from the probiotic was found in the gut of people who took the probiotic, in two of the three groups. Limosilactobacillus fermentum was found in only one person who took the probiotic.
Other bacterial changes
Both maltodextrin and the probiotic changed the levels of various other gut bacteria, such as Faecalibacterium, Blautia, and Alistipes. The direction of these changes differed between the three groups.
Sleep and mood
In one group, people who took the probiotic had better sleep quality and lower scores for anger, depression, and fatigue. These changes were not significant in the other groups.
What the authors conclude
“a bifidogenic effect of maltodextrin, used as placebo, was observed”
Also in their conclusions
- They suggest that participants were subjected to two different treatments rather than one: a 'synbiotic' administration (probiotics and maltodextrin) and a 'prebiotic' assumption (maltodextrin).
- They advise that the bifidogenic effect of maltodextrins needs to be deeply evaluated in future clinical trials involving bifidobacteria.
- They highlight the importance of defining bacteriotypes to assess the impact of interventions on the gut microbiota.
How it was done
The authors wanted to see how a probiotic product and its maltodextrin placebo affected the gut bacteria of healthy people, and whether different starting gut bacteria types led to different responses.
They analysed stool samples from 33 healthy adults who had taken either a probiotic mixture in maltodextrin or a maltodextrin-only placebo for 6 weeks, followed by a 3-week washout. Samples were collected before treatment, at 3 and 6 weeks, and after the washout.
What it can’t tell you
- This was a small study of 33 healthy adults, so the results may not apply to other people.
- The study cannot show whether the changes in gut bacteria caused the improvements in sleep and mood.
- The authors did not include a true placebo group without maltodextrin, so the specific effect of maltodextrin alone is not clear.
Who paid
- Authors work at
- University of Verona, Italy
The paper
- Title
- Metabarcoding analysis of gut microbiota of healthy individuals reveals impact of probiotic and maltodextrin consumption
- Type
- Clinical trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Calgaro M, Pandolfo M, Salvetti E, et al (2021). Metabarcoding analysis of gut microbiota of healthy individuals reveals impact of probiotic and maltodextrin consumption. Beneficial microbes. doi:10.3920/BM2020.0137Free full textPubMed 33789555DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error