Mushrooms, meat and gut health in healthy adults
What it found
In 32 healthy adults, eating mushrooms twice daily for ten days led to heavier stools and a different mix of gut bacteria than eating meat, but no clear change in gut fermentation acids.
The mushroom diet also caused more gas and bloating in the first two days.
What they found
Studies in people
Gut symptoms
On days one and two, people reported more overall gut symptoms, gas and flatulence on the mushroom diet than the meat diet. By day ten, there was no difference between the diets.
Stool weight
Stool weight was higher on the mushroom diet than the meat diet. Stool frequency, pH and consistency did not differ between the diets.
Gut bacteria
The mushroom diet led to a different mix of gut bacteria, with more Bacteroidetes and less Firmicutes than the meat diet. Levels of Lactobacilli and Bifidobacteria were low on both diets and did not change.
Fermentation acids
There were no differences between the diets in most short chain fatty acids measured in stool. One acid, isovalerate, was higher on the meat diet.
Breath gases
Breath hydrogen and breath methane did not differ between the two diets.
Undigested mushroom
About one third of participants had visible pieces of mushroom in their stool at least once during the mushroom treatment. This suggests some mushroom material was not broken down.
What the authors conclude
“The increase in stool weight and presence of undigested mushrooms in stool suggests that mushroom consumption may impact laxation in healthy adults.”
Also in their conclusions
- They say the increase in stool weight, the lack of increase in short chain fatty acids, and the presence of undigested mushroom in stool suggest that mushrooms may be only partially fermentable by human gut bacteria.
- They call for further research to see whether chewing or other digestive processes could make the carbohydrates in mushrooms more available.
- They also say more investigation is needed to work out what the changes in gut bacteria might mean for health.
How it was done
Mushrooms contain carbohydrates that people cannot fully digest, and these might feed gut bacteria. The authors wanted to test this in people, since earlier work had only been done in animals.
They ran a randomised trial in 32 healthy adults, comparing protein-matched amounts of mushrooms or meat eaten twice daily for ten days each, with a ten-day break in between. They measured gut symptoms, breath gases, stool weight and consistency, stool acids, and gut bacteria.
What it can’t tell you
- The study did not collect stool samples before the diets started, so it cannot show how each diet changed the gut bacteria from a person's usual baseline.
- The trial lasted only ten days, so it cannot show what would happen over a longer period.
- The health effects of the bacterial shifts seen are not known.
Who paid
- Funding
- Funded by NCATS NIH HHS; Mushroom Council (from the PubMed record).
- Conflicts
- The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.
- Authors work at
- University of Minnesota, USA
The paper
- Title
- Impact of Agaricus bisporus Mushroom Consumption on Gut Health Markers in Healthy Adults
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Hess J, Wang Q, Gould T, Slavin J (2018). Impact of Agaricus bisporus Mushroom Consumption on Gut Health Markers in Healthy Adults. Nutrients. doi:10.3390/nu10101402Free full textPubMed 30279332DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error