Soluble corn fiber and polydextrose changed gut bacteria in healthy men
What it found
Eating 21 g a day of soluble corn fiber or polydextrose shifted the mix of gut bacteria in 20 healthy men.
Both fibers raised levels of a bacteria type linked to lower inflammation.
What they found
Studies in people
More anti-inflammatory bacteria
Both fibers raised levels of Faecalibacterium prausnitzii in the men's stool. This specific gut bacteria is known for its ability to lower inflammation.
Lactobacillus rose with corn fiber
Only soluble corn fiber increased Lactobacillus, a group of bacteria often used as probiotics. Polydextrose did not raise this type.
Fewer protein waste products
Men eating either fiber had lower amounts of ammonia, phenol, and indole in their stool. These are waste products made when gut bacteria break down protein.
Overall bacterial diversity unchanged
The total variety of gut bacteria stayed about the same across all three snack bar periods. The fibers changed which types were present but not the overall number of types.
Corn fiber lowered stool pH
Stool was slightly more acidic when men ate soluble corn fiber compared to the bars with no added fiber. The pH dropped from 6.4 to 6.2.
What the authors conclude
- They say that eating polydextrose or soluble corn fiber led to helpful shifts in gut bacteria, mainly within the Firmicutes group.
- The authors suggest these changes could help correct imbalances in gut bacteria linked to certain diseases.
- They support using these novel fibers as prebiotics in human diets.
How it was done
Most Americans eat far less fiber than recommended, and scientists know little about how newer fibers like soluble corn fiber and polydextrose change gut bacteria. The authors wanted to see if these fibers could shift gut bacteria in helpful ways.
Twenty healthy men aged 20 to 40 ate three snack bars a day for 21 days at a time. The bars contained either no added fiber, 21 g of polydextrose, or 21 g of soluble corn fiber. Researchers tested stool samples collected during the last five days of each period to look at gut bacteria.
What it can’t tell you
- This trial only included healthy men aged 20 to 40, so it cannot show what happens in women, children, or older adults.
- The study lasted 21 days per treatment, so it cannot show whether these changes in gut bacteria last over months or years.
- The researchers did not measure blood sugar or cholesterol, so they cannot link these bacterial shifts to those health markers.
Who paid
- Authors work at
- University of Illinois, USA
The paper
- Title
- 454 pyrosequencing reveals a shift in fecal microbiota of healthy adult men consuming polydextrose or soluble corn fiber
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Hooda S, Boler BM, Serao MC, et al (2012). 454 pyrosequencing reveals a shift in fecal microbiota of healthy adult men consuming polydextrose or soluble corn fiber. The Journal of nutrition. doi:10.3945/jn.112.158766Free full textPubMed 22649263DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error