Research

Hormonal

Short-term high-dose supplementation with Fructooligosaccharides (FOS) or Galactooligosaccharides (GOS) in healthy young adults causes adverse glycemic metabolism by reducing butyrate-producing bacteria.

If you are healthy, taking high doses of FOS or GOS (16g/day) for short periods might actually worsen your blood sugar response. This contradicts the common belief that prebiotics always help glucose control. The effect is linked to a drop in butyrate-producing bacteria.

GoodRefutesHIGH confidence
Short-term intake of high-dose prebiotics had adverse effect on glucose metabolism, as in FOS intervention demonstrated by OGTT (P < 0.001), and in GOS intervention demonstrated by fasting glucose (P < 0.05).
Feitong Liu et al. · Scientific Reports · 2017

Why this rating

Randomized double-blind cross-over study with 35 healthy adults, though short duration (14 days).

Source

Fructooligosaccharide (FOS) and Galactooligosaccharide (GOS) Increase Bifidobacterium but Reduce Butyrate Producing Bacteria with Adverse Glycemic Metabolism in healthy young population

Feitong Liu et al. · Scientific Reports · 2017

DOI 10.1038/s41598-017-10722-2

crossover · n=35Cited 297×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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