Fructooligosaccharide and blood sugar across animal and human studies
What it found
In people with type 2 diabetes, adding fructooligosaccharide to the diet sometimes lowered blood sugar.
In healthy people, it mostly made no difference.
What they found
Studies in people
Blood sugar in diabetic people
One study gave 8 grams daily for 14 days to people with type 2 diabetes whose blood sugar was not well controlled. Their fasting blood sugar dropped by 8%. Another study using 15 grams for 20 days in similar patients found no changes.
Blood sugar in healthy people
Taking 20 grams a day lowered sugar production in the liver but did not change how insulin handled sugar. A separate study using 10.6 grams a day found no effect on blood sugar at all.
Compared to regular sugar
Unlike regular table sugar, taking 25 grams of these sugars did not raise blood sugar or fructose levels after eating.
Animal and lab studies
Propionate effects in rats
In rat studies, very high doses of propionate (a fatty acid made when gut bacteria break down these sugars) lowered blood sugar. Lower doses of 3 g/kg did not have the same result.
Other findings
How the body handles FOS
These sugars pass through the stomach and small intestine without being broken down. Gut bacteria ferment them in the colon, producing gases and short-chain fatty acids. The fermented portion provides 2 kcal per gram.
What the authors conclude
- They conclude that eating these sugars has a helpful influence on how the body handles glucose.
- They suggest that adding them to the diet could be a way to lower blood sugar.
- They note that the right dose and how long to take it still need more research.
How it was done
The authors wanted to gather what is known about how fructooligosaccharides affect blood sugar control. These sugars are often mentioned in dietary advice for conditions linked to metabolic problems.
They searched two databases for articles published between January 1962 and December 2011. From 434 references found, they included 43 in their summary. They grouped the texts into three topics: how the body handles these sugars, animal tests, and human tests.
What it can’t tell you
- This work gathers past studies rather than testing people directly, so it cannot prove cause and effect on its own.
- Some of the included studies had very few participants or design flaws, which makes their results less certain.
- Animal tests using very high doses of related compounds may not reflect what happens in people eating normal amounts.
Who paid
- Authors work at
- Federal University of Amazon, Brazil
The paper
- Title
- Fructo-oligosaccharide effects on blood glucose: an overview
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Costa GT, Guimarães SB, Sampaio HA (2012). Fructo-oligosaccharide effects on blood glucose: an overview. Acta cirurgica brasileira. doi:10.1590/s0102-86502012000300013Free full textPubMed 22460261DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error