Skip to main content
Evidence-Based Supplement Research
Evidence-Based Supplement Research
Pillser
Search
Sign UpLog In

Effect of yacon (Smallanthus sonchifolius) on colonic transit time in healthy volunteers.

  • 2008-09-10
  • Digestion 78(1)
    • M Geyer
    • I Manrique
    • L Degen
    • C Beglinger

Study Design

Type
Randomized Controlled Trial (RCT)
Population
16 healthy individuals (8 males, 8 females)
Methods
Placebo-controlled, double-blind study; yacon syrup 20 g daily (equal to 6.4 g FOS) in a 2-week crossover design with 2-week wash-out phase
Blinding
Double-blind
Duration
2 weeks

Background

Yacon is a root crop which contains high amounts of fructooligosaccharides (FOS). The aim of this study was to investigate the effects of yacon syrup on colon transit time in healthy volunteers.

Methods

In a placebo-controlled, double-blind study yacon was administered to 16 healthy individuals (8 males, 8 females) in a dose of 20 g daily (equal to 6.4 g FOS) in a 2-week crossover design. Each period was interrupted by a 2-week wash-out phase. Transit time was assessed by a radio-opaque marker technique.

Results

Transit time (mean +/- SEM) through the gastrointestinal tract was significantly decreased from 59.7 +/- 4.3 to 38.4 +/- 4.2 h (p < 0.001). Yacon was well tolerated with an excellent side effect profile. Bloating is not an uncommon side effect observed with FOS, but bloating-related disturbances were not significantly more often reported with yacon compared to placebo. Stool frequency increased from 1.1 +/- 0.1 to 1.3 +/- 0.2 times per day and the consistency showed a tendency for softer stools as assessed by a numerical depicted stool protocol. Neither parameter did, however, reach statistical significance.

Conclusion

Yacon markedly accelerates colonic transit in healthy individuals. Further studies are needed in constipated patients to confirm these preliminary data. Due to the low caloric content of yacon, the root could be a useful treatment in constipated diabetics or obese patients.

Research Insights

  • Yacon→Improved Bowel Movement Frequency

    Stool frequency increased from 1.1 +/- 0.1 to 1.3 +/- 0.2 times per day ... Neither parameter did, however, reach statistical significance.

    Effect
    Neutral
    Effect size
    Small
    Dose
    20 g daily (equal to 6.4 g FOS)
  • Yacon→Improved Stool Consistency

    ...the consistency showed a tendency for softer stools as assessed by a numerical depicted stool protocol. Neither parameter did, however, reach statistical significance.

    Effect
    Neutral
    Effect size
    Small
    Dose
    20 g daily (equal to 6.4 g FOS)
  • Yacon→Reduced Colonic Transit Time

    Transit time (mean +/- SEM) through the gastrointestinal tract was significantly decreased from 59.7 +/- 4.3 to 38.4 +/- 4.2 h (p < 0.001).

    Effect
    Beneficial
    Effect size
    Large
    Dose
    20 g daily (equal to 6.4 g FOS)

Adverse Events Reported

  • Yacon→bloating

    Bloating is not an uncommon side effect observed with FOS, but bloating-related disturbances were not significantly more often reported with yacon compared to placebo.

    Finding
    No significant difference
    Significant
    No
  • Yacon→Overall tolerability

    Yacon was well tolerated with an excellent side effect profile.

    Finding
    Reported
Back to top