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Digestion/Mobility/Weight

Fructooligosaccharides

Prebiotic fiber that feeds beneficial gut bacteria, improves bowel regularity, and enhances calcium absorption for adults with low fiber intake.

Fructooligosaccharides

Fructooligosaccharides

60
score
B
evidence
Safe
risk

Proven Benefits

01Improves bowel regularity
02Supports calcium absorption
03May increase satiety
04May support glycemic control

Chemical Forms

Recommended
  • Oligofructose
  • Chicory root FOS
  • Short-chain fructooligosaccharides
Avoid
  • Inulin (longer-chain fructan, slower fermentation, more bloating risk at equivalent doses)
Expert Note

Short-chain FOS (oligofructose) ferments more rapidly in the proximal colon and typically produces less gas and bloating than longer-chain inulin. Chicory-derived FOS has the strongest human clinical data for both microbiome modulation and mineral absorption.

Protocol

Amount
5-10 g
Frequency
Once daily
When
Split into 2 doses with meals to reduce bloating, or take once daily with breakfast.

Condition-Based Dosing

General prebiotic support
5 g daily
Constipation
8-10 g daily
Calcium absorption support
8 g daily

Safety & Limits

Upper Safe Limit
No official UL established; doses above 30 g/day commonly cause diarrhea and severe bloating (functional fiber tolerance guidance)
Cycling
Safe for continuous use

Contraindications

Small intestinal bacterial overgrowth (SIBO) — FOS may worsen bloating by feeding proximal gut bacteria
Hereditary fructose intolerance — FOS contains fructose moieties that cannot be properly metabolized
Inflammatory bowel disease (IBD) during flares — fermentable fibers may exacerbate gas, pain, and diarrhea
FODMAP-sensitive irritable bowel syndrome (IBS) — FOS is a FODMAP and may trigger symptoms

Synergies

Calcium

FOS acidifies the colonic lumen and improves calcium solubility, enhancing absorption in the distal intestine.

Magnesium

FOS fermentation increases magnesium solubility and absorption in the colon via a mechanism similar to calcium.

Vitamin D3

Vitamin D upregulates intestinal calcium transporters; pairing with FOS may maximize total calcium uptake.

Avoid Combining With

  • ✕Antibiotics (separate by 2+ hours — may reduce prebiotic fermentation and transiently alter microbiome)
  • ✕Some medications (take 2 hours before or after — fiber may reduce absorption of certain drugs)
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