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Yacon Syrup

Smallanthus sonchifolius
Evidence Level
Limited
3 Clinical Trials
5 Documented Benefits
2/5 Evidence Score

Yacon syrup is a natural sweetener made from the yacon root, rich in fructooligosaccharides (FOS), a type of prebiotic fiber. Because much of it is fiber rather than digestible sugar, it is lower in usable calories and acts as a prebiotic, feeding beneficial gut bacteria, which is why it is marketed as a lower-glycemic sweetener and for digestive and weight support. It is used as a syrup to sweeten foods. Because of its high FOS content, larger amounts can cause gas, bloating, or a laxative effect, especially at first, so it is best started in small amounts, and those with sensitive guts or FODMAP sensitivity should use it cautiously.

Studied Dose 0.14 g FOS/kg/day (~10 g FOS, or 20-25 g syrup for a 70-kg adult). Commercial syrup FOS varies 40-65%.
Active Compound Fructooligosaccharides (FOS) — primarily inulin-type fructans (40-70% of dry weight).

Benefits

Body Weight, Waist, and BMI Reduction

An RCT in obese pre-menopausal women showed significant decreases in body weight, waist circumference, and BMI with yacon syrup at 0.14 g FOS/kg/day. The effect size was modest but clinically meaningful in this population.

Supported by Trial 1

Insulin Resistance Improvement

Trial data documented significant decreases in fasting serum insulin and HOMA-IR (Homeostasis Model Assessment for Insulin Resistance) in participants with baseline elevated HOMA-IR. No effect on fasting glucose (already normo-glycemic). Effects align with FOS-mediated GLP-1 elevation and gut microbiome modulation.

Supported by Trial 1

LDL Cholesterol Reduction

Trial data found a significant decrease in serum LDL-cholesterol with yacon syrup, while total cholesterol and triglycerides were not significantly changed. A systematic review confirmed LDL reduction as a consistent finding across yacon trials.

Supported by Trial 2, Trial 1

Increased Defecation Frequency and Satiety

Trial data documented increased defecation frequency and satiety sensation with yacon syrup. FOS is a well-established prebiotic and bulk-forming dietary fiber; satiety effects likely involve FOS-mediated GLP-1 and PYY elevation. Gut transit benefits are consistent across studies.

Supported by Trial 1, Trial 2

Prebiotic / Gut Microbiome Support

FOS is selectively fermented by Bifidobacterium and Lactobacillus species, supporting beneficial gut microbiome composition. This is the same mechanism as inulin and other fructan prebiotics. A systematic review noted improvements in intestinal transit and gut microbiota across yacon trials.

Supported by Trial 2

Mechanism of action

1

Fructooligosaccharide (FOS) Prebiotic Effect

Yacon syrup is exceptionally rich in inulin-type FOS (40-70% of dry weight) — among the highest natural sources known. FOS is non-digestible by human enzymes but selectively fermented by colonic Bifidobacterium and Lactobacillus, producing short-chain fatty acids (SCFAs: acetate, propionate, butyrate) with metabolic and anti-inflammatory benefits.

2

GLP-1 and PYY Elevation (Incretin/Satiety Hormones)

Colonic SCFA production from FOS fermentation stimulates L-cell secretion of GLP-1 (incretin, postprandial insulin enhancer) and PYY (peptide YY, satiety hormone). This explains the satiety and insulin sensitivity benefits documented in trials.

3

Reduced Caloric Density (Low-Glycemic Sweetener)

FOS provides ~1.5-2 kcal/g vs. ~4 kcal/g for sucrose — and most of those calories come from colonic SCFAs that are partially used by gut bacteria. As a sweetener replacement, yacon syrup substantially reduces glycemic load and net caloric impact.

4

Bulk Stool Formation and Transit

Like other soluble fibers, FOS adds water-binding bulk to stool and may accelerate colonic transit. This explains the increased defecation frequency seen in trials and supports general gut health applications.

5

Modest Mineral Absorption Enhancement

FOS may modestly enhance calcium and magnesium absorption via colonic SCFA-induced mineral solubilization. Effects are real but usually small; relevance for osteoporosis prevention is mechanism-based rather than RCT-confirmed for yacon specifically.

Clinical trials

1
Yacon Syrup for Obesity and Insulin Resistance (Foundational Clinical Trial)

Double-blind, placebo-controlled trial. Two doses of yacon syrup (0.29 g and 0.14 g FOS/kg/day) vs. placebo for 120 days in obese pre-menopausal women. Anthropometric measurements, blood glucose, calcium, lipid and insulin concentrations, HOMA-IR. (Genta, Cabrera, Habib, Pons, Carillo, Grau, Sánchez 2009, Clin Nutr)

Obese, slightly dyslipidemic pre-menopausal women with baseline insulin resistance (HOMA-IR > 2.70).

Recommended dose without GI side effects: 0.14 g FOS/kg/day. Significant decreases in body weight, waist circumference, and BMI. Significant decreases in fasting serum insulin and HOMA-IR. Significant LDL cholesterol reduction. Increased defecation frequency and satiety sensation. Fasting glucose unchanged. Higher dose (0.29 g/kg) caused GI side effects. Foundational clinical trial establishing yacon syrup as a beneficial functional food for obese insulin-resistant women.

2
Yacon Syrup Human Health Evidence Review

PRISMA-compliant evidence review of yacon syrup clinical trials over the last decade. Searched Medline (PubMed), Science Direct, Embase, Scopus, SciELO through. Inclusion: clinical trials of yacon syrup on glycemic control, lipid profile, insulin sensitivity, appetite regulation, gut microbiota in healthy/overweight/obese individuals. (Nutrients)

7 clinical trials included, totaling 161 participants from diverse populations.

Yacon syrup supplementation demonstrated significant reductions in fasting insulin, HOMA-IR, and LDL cholesterol, alongside improvements in satiety and intestinal transit. Findings were consistent across trial heterogeneity. Authors noted evidence quality concerns (small sample sizes, dose variability) and called for larger trials.

3
Yacon Flour for Body Composition and Bowel Function

Randomized, double-blind, placebo-controlled clinical trial of yacon flour vs. placebo in overweight adults. Outcomes: body composition, intestinal function. (Machado, da Silva, Chaves, Clin Nutr ESPEN)

Overweight adults.

Yacon flour consumption improved body composition and intestinal function vs. placebo. Provides additional evidence beyond syrup form that yacon-derived FOS supports weight management and gut function. Effect sizes modest but consistent with mechanism.

Side effects and drug interactions

Common Potential side effects

GI symptoms (gas, bloating, abdominal cramping, diarrhea) at doses above 0.14 g FOS/kg/day or with rapid dose escalation. Start low and increase gradually.
Possible osmotic diarrhea at high doses.
Allergic reactions are uncommon but documented (one case report of anaphylaxis after yacon ingestion: PMID 20358031).
FOS may aggravate symptoms in IBS or SIBO (small intestinal bacterial overgrowth) due to fermentation.
Not appropriate for those on low-FODMAP diets.
Pregnancy and lactation: yacon is consumed as food in Andean regions; supplemental yacon syrup at moderate doses is likely safe but rigorous data is absent.
Children: introduce gradually; high doses may cause GI symptoms more readily.

Important Drug interactions

Diabetes medications (insulin, sulfonylureas): yacon's insulin sensitivity effects may be additive — monitor blood glucose.
Other prebiotics or probiotics: generally synergistic; no specific concerns.
Iron supplements: theoretical interaction via mineral absorption changes — clinical relevance unclear.
Antibiotics: short-term yacon use during antibiotic courses may help maintain microbiome balance, though this is not specifically RCT-demonstrated.
No major drug interactions documented.

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Frequently asked questions about Yacon Syrup

What is yacon syrup?

Yacon syrup is a natural sweetener from the yacon root, rich in fructooligosaccharides (FOS), a type of prebiotic fiber. Because much of it is fiber rather than digestible sugar, it is lower in usable calories and acts as a prebiotic.

What is yacon syrup used for?

It is used as a lower-glycemic sweetener and as a prebiotic to feed beneficial gut bacteria, and it is sometimes marketed for digestive regularity and weight support. Its FOS content is the active component.

Does yacon syrup cause digestive issues?

Because it is high in FOS prebiotic fiber, larger amounts can cause gas, bloating, or a laxative effect, especially at first. Start with small amounts (such as a teaspoon) to assess tolerance.

Is yacon syrup safe?

It is generally safe as a food sweetener. The main consideration is digestive tolerance due to its fiber content. People with sensitive guts or FODMAP sensitivity should use it cautiously.

What is the recommended dosage of Yacon Syrup?

The clinically studied dose is 0.14 g FOS/kg/day (~10 g FOS, or 20-25 g syrup for a 70-kg adult). Commercial syrup FOS varies 40-65%. Always follow the product label and check with a healthcare provider for personal advice.

Is Yacon Syrup safe, and does it have side effects?

For most healthy adults, Yacon Syrup is well tolerated at studied doses. Reported effects can include: GI symptoms (gas, bloating, abdominal cramping, diarrhea) at doses above 0.14 g FOS/kg/day or with rapid dose escalation. Start low and increase gradually. Possible osmotic diarrhea at high doses. It may also interact with some medications. Yacon Syrup is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Yacon Syrup interact with any medications?

Possible interactions include: Diabetes medications (insulin, sulfonylureas): yacon's insulin sensitivity effects may be additive — monitor blood glucose. Other prebiotics or probiotics: generally synergistic; no specific concerns. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Yacon Syrup?

NutraSmarts rates the evidence for Yacon Syrup as Limited (2 out of 5). It is backed by 3 clinical trials and 2 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(2 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Genta S, Cabrera W, Habib N, Pons J, Carillo IM, Grau A, Sánchez S Yacon syrup: beneficial effects on obesity and insulin resistance in humans Clinical Nutrition. 2009;28(2):182-7. doi:10.1016/j.clnu.2009.01.013.PubMedUsed to support: Pivotal placebo-controlled RCT in pre-menopausal obese women over 120 days showing yacon syrup significantly reduced body weight, waist circumference, BMI, fasting insulin, and LDL cholesterol; supports Body Weight/BMI Reduction, Insulin Resistance Improvement, LDL Cholesterol Reduction, and Increased Defecation Frequency and Satiety.
  2. Pereira MF, Soares IC, Cabral MM, and colleagues Impacts of Yacon Syrup (Smallanthus sonchifolius) on Human Health: A Systematic Review of Scientific Evidence from the Last Decade Nutrients. 2025;17(5):888. doi:10.3390/nu17050888.PubMedUsed to support: Systematic review of seven clinical trials (161 participants) confirming yacon syrup supplementation produced significant reductions in body weight, BMI, and LDL cholesterol across studies; supports Body Weight/BMI Reduction, LDL Cholesterol Reduction, and Prebiotic/Gut Microbiome Support.