Inulin plus resistant dextrin in older people's gut samples
What it found
In lab tests using stool samples from seven older people, combining inulin with resistant dextrin led to less gas and greater gut bacteria diversity than inulin alone, while keeping up the growth of Bifidobacterium and short-chain fatty acid production.
What they found
Animal and lab studies
Gas production
The combination with 0.25% inulin and 0.25% resistant dextrin produced less gas than 0.5% inulin alone. The 0.5% inulin plus 0.5% resistant dextrin combination produced more gas than 0.5% inulin alone.
Bifidobacterium growth
All groups containing inulin had significantly higher Bifidobacterium counts than the group with only resistant dextrin. The 0.5% inulin group had the highest proportion of Bifidobacterium (26.1%), followed by the 0.5% combination (17.7%), the 0.25% combination (15.1%), and the resistant dextrin alone group (5.8%).
Gut bacteria diversity
The 0.25% inulin plus 0.25% resistant dextrin combination led to significantly greater gut bacteria diversity than 0.5% inulin alone. The 0.5% inulin group had the lowest diversity.
Short-chain fatty acids
Acetate levels were significantly higher in all inulin-containing groups than in the resistant dextrin alone group. Propionate and butyrate levels did not differ significantly between groups, but were higher in inulin groups than in the resistant dextrin alone group.
pH change
The pH in the 0.5% inulin group increased after 14 hours of fermentation. At 24 hours, the pH was higher in the 0.5% inulin group than in the 0.25% combination group and significantly higher than in the 0.5% combination group.
Fiber use
Inulin was completely used up by the gut bacteria after 24 hours, while resistant dextrin remained. This suggests resistant dextrin is used more slowly.
What the authors conclude
“These findings suggest that the inulin plus resistant dextrin combination has superior prebiotic effects in older people and causes less gas production than inulin alone.”
Also in their conclusions
- They suggest that the inulin plus resistant dextrin combination has superior prebiotic effects in older people and causes less gas production than inulin alone.
- They say these findings can be applied to the development of food products combining inulin with resistant dextrin for older people, which would provide a prebiotic that also addresses the issue of abdominal symptoms.
- They call for further clinical trials to confirm whether this composition exhibits prebiotic effects while reducing abdominal symptoms in older people.
How it was done
Older people's gut bacteria tend to decline, and prebiotics like inulin can help, but inulin causes a lot of gas and bloating. The authors wanted to see if mixing inulin with resistant dextrin, a slower-fermented fiber, could reduce gas while still feeding beneficial bacteria.
They collected stool samples from seven healthy older Japanese people (average age 73.4 years, five men and two women) and fermented them in the lab with different combinations of inulin and resistant dextrin for 24 hours. They measured gas production, bacterial counts, short-chain fatty acids, and pH.
What it can’t tell you
- This was a lab study using stool samples, not people. It cannot show what happens inside the human gut.
- The study used samples from only seven older people, so the results may not apply to all older adults.
- The prebiotics were given only once, so it is unclear whether long-term intake would have the same effects.
Who paid
- Conflicts
- K.Y., E.K., S.M., H.S. and K.M. are employees of and receive a salary from Morinaga Milk Industry Co., Ltd.
- Authors work at
- Health Care & Nutritional Science Institute, Japan
The paper
- Title
- Combination of Inulin and Resistant Dextrin Has Superior Prebiotic Effects and Reduces Gas Production During In Vitro Fermentation of Fecal Samples from Older People
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Cite
- Yoshida K, Kokubo E, Morita S, Sonoki H, Miyaji K (2024). Combination of Inulin and Resistant Dextrin Has Superior Prebiotic Effects and Reduces Gas Production During In Vitro Fermentation of Fecal Samples from Older People. Nutrients. doi:10.3390/nu16244262Free full textPubMed 39770884DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error