Open Food Labels. Search 352 ingredients⌘K

Randomised trial · Nutrients · 2019Conflicts declared

Guar gum fiber and loose stools in healthy adults

Yasukawa Z, Inoue R, Ozeki M, et al · Free full text

What it found

In 44 healthy adults with loose stools, taking partially hydrolyzed guar gum for 3 months made stool firmer and increased Bifidobacterium in the gut.

Stool frequency did not change.

What they found

Studies in people

Stool form improved

Stool form on the Bristol scale became firmer in the guar gum group from week 3 to week 16 compared with baseline, and was significantly firmer than placebo at weeks 7 and 11.

Stool frequency unchanged

There was no difference between groups in how often people had bowel movements at any time point.

Gut bacteria shifted

The guar gum group had a significant increase in Bifidobacterium and in the phylum Actinobacteria, and increases in Ruminococcus and Megasphaera, while Bacteroides and some other groups decreased.

Bile acids changed

The conversion of primary to secondary bile acids in serum decreased significantly in the guar gum group after 12 weeks, but not in the placebo group.

Quality of life

Mental-component summaries tended to be higher in the guar gum group at 4 weeks, with some social functioning scores significantly better at 8 and 12 weeks.

Side effects

Reported events like constipation, diarrhea, colds and abdominal discomfort were transient and judged not to be related to the test food.

What the authors conclude

“In conclusion, this study demonstrated that PHGG normalized stool consistency, helping volunteers with loose stools get closer to a BSS score of 4.”
Yasukawa Z, Inoue R, Ozeki M, et al, 2019

Also in their conclusions

  • They conclude that partially hydrolyzed guar gum normalized stool consistency, helping volunteers with loose stools get closer to a Bristol score of 4.
  • They say this effect may work through changes in gut bacteria, which may also improve mental quality of life.
  • They call for larger studies with multiple doses to confirm the findings.

How it was done

The authors wanted to test whether this water-soluble fiber helps people with a tendency toward diarrhea, since few studies have looked at that.

They randomly assigned 44 healthy Japanese adults with loose stools to take 5 g of partially hydrolyzed guar gum or a placebo daily for 12 weeks, then followed a 4-week washout. Stool form, frequency, gut bacteria, bile acids and quality of life were measured.

What it can’t tell you

  • This trial was in healthy adults with loose stools, so the results may not apply to people with diagnosed irritable bowel syndrome or other conditions.
  • The study was relatively small and tested only one dose of guar gum, so it cannot show whether different doses would work better or worse.

The paper

Title
Effect of Repeated Consumption of Partially Hydrolyzed Guar Gum on Fecal Characteristics and Gut Microbiota: A Randomized, Double-Blind, Placebo-Controlled, and Parallel-Group Clinical Trial
Type
Randomised controlled trial
Evidence
Studies in people
Summarised from
Full text
Cite
Yasukawa Z, Inoue R, Ozeki M, et al (2019). Effect of Repeated Consumption of Partially Hydrolyzed Guar Gum on Fecal Characteristics and Gut Microbiota: A Randomized, Double-Blind, Placebo-Controlled, and Parallel-Group Clinical Trial. Nutrients. doi:10.3390/nu11092170Free full textPubMed 31509971DOI

Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error