Isomalto-oligosaccharide and inulin for constipation in rats
What it found
In rats with constipation, isomalto-oligosaccharide and inulin increased how often and how much the rats pooped and how much water the pellets held.
The rats also had different levels of gut hormones and gut bacteria.
What they found
Animal and lab studies
Poop output and timing
In constipated rats, both inulin and isomalto-oligosaccharide increased the number, weight and water content of fecal pellets. They also shortened the time to the first black stool.
Gut hormones in blood
Rats given the prebiotics had higher blood levels of ACTH, motilin and Substance P than untreated constipated rats. They had lower levels of corticosterone, VIP and CGRP.
Hormones in colon tissue
In colon tissue, the prebiotics raised motilin and Substance P and lowered VIP and CGRP.
Short-chain fatty acids
In constipated rats, inulin and isomalto-oligosaccharide increased the amount of short-chain fatty acids in the colon contents.
Gut bacteria changes
The Bacteroidetes group of bacteria was less abundant in the prebiotic groups than in the control groups. Lactobacillus was more abundant in the inulin and isomalto-oligosaccharide groups than in untreated constipated rats.
Specific Lactobacillus species
Lactobacillus reuteri and Lactobacillus intestinalis were more abundant in the isomalto-oligosaccharide group than in untreated constipated rats. L. intestinalis was also more abundant in the inulin group.
What the authors conclude
“In summary, INU and IMO improved constipation and altered the intestinal microbiota in a rat model of constipation.”
Also in their conclusions
- They conclude that inulin and isomalto-oligosaccharide improved constipation and altered the gut bacteria in a rat model of constipation.
How it was done
The authors say these prebiotics affect gut health and immunity, but their effects on constipation are not clearly established.
Twenty-four male rats were split into four groups. One group got a basal diet, one got diphenoxylate to cause constipation, and two got either inulin or isomalto-oligosaccharide at 20 g kg-1 along with diphenoxylate.
What it can’t tell you
- We summarised it from the abstract only.
- These are rat studies. They can't show what happens in people.
- The rats were made constipated with a drug, so the results may not apply to other kinds of constipation.
Who paid
- Authors work at
- Zhejiang A & F University, China; China Jiliang University, China
The paper
- Title
- Effects of inulin and isomalto-oligosaccharide on diphenoxylate-induced constipation, gastrointestinal motility-related hormones, short-chain fatty acids, and the intestinal flora in rats
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Abstract only
- Cite
- Lan J, Wang K, Chen G, Cao G, Yang C (2020). Effects of inulin and isomalto-oligosaccharide on diphenoxylate-induced constipation, gastrointestinal motility-related hormones, short-chain fatty acids, and the intestinal flora in rats. Food & function. doi:10.1039/d0fo00865fPubMed 33030479DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error