Supplement
Fiber is the part of plant foods your body can't digest, and it adds bulk to stool, softens it and slows how quickly carbohydrates are absorbed. People most often look at it for constipation-predominant irritable bowel syndrome, where the evidence is strong, especially for soluble fiber. Findings elsewhere were more modest: blood glucose improved in pregnancies with diabetes, though the studies were small, and appetite showed no clear difference.
Sources: PMID 39473074
- Updated
- How we grade
- 5 studies cited
- Best evidence
- Grade B
- Conditions studied
- 6
- Outcomes
- 24
- Graded outcomes
- 0402
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Blood glucose Small Improvement | Improves (the measure goes down) | Small effect | 1 study | 1,061 people | ||
Studies that measured blood glucose | ||||||
| HbA1c | Improves (the measure goes down) | 1 study | 1,061 people | |||
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Glycemic Control Small Improvement | Improves (the measure goes up) | Small effect | 64 people | |||
| HbA1c | Improves (the measure goes down) | 1 study | 87 people | |||
Type 2 Diabetes
- High-density lipoprotein (HDL): improves
- Total cholesterol: improves
- Low-density lipoprotein (LDL): improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| High-density lipoprotein (HDL) Small Improvement | Improves (the measure goes up) | Small effect | 2,580 people | |||
| Total cholesterol | Improves (the measure goes down) | 2 studies | 2,580 people | |||
Studies that measured total cholesterol | ||||||
| Low-density lipoprotein (LDL) | Improves (the measure goes down) | 2,580 people | ||||
| Triglycerides | Improves (the measure goes down) | 2,580 people | ||||
Metabolic Health
- High-density lipoprotein (HDL): improves
- Total cholesterol: improves
- Low-density lipoprotein (LDL): improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| High-density lipoprotein (HDL) Small Improvement | Improves (the measure goes up) | Small effect | 291 people | |||
| Total cholesterol | Improves (the measure goes down) | 2 studies | 334 people | |||
Studies that measured total cholesterol | ||||||
| Low-density lipoprotein (LDL) | Improves (the measure goes down) | 334 people | ||||
| Triglycerides | Improves (the measure goes down) | 311 people | ||||
Chronic Kidney Disease (CKD)
- C-Reactive Protein (CRP)
- Blood Urea Nitrogen
- Interleukin 6: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| C-Reactive Protein (CRP) No effect | NoneNo effect | 157 people | ||||
| Blood Urea Nitrogen | Small effect | 1 study | 498 people | |||
| Interleukin 6 | Improves (the measure goes down) | 265 people | ||||
| p-cresyl sulfate (PCS) | Improves (the measure goes up) | 398 people | ||||
| Serum Indoxyl Sulfate (IS) | Improves (the measure goes up) | 398 people | ||||
| TMAO | Improves (the measure goes up) | 135 people | ||||
| TNF-Alpha | Improves (the measure goes down) | 157 people | ||||
| Uric Acid | Improves (the measure goes down) | 118 people | ||||
Weight Loss & Maintenance
- Appetite
- Liver Fat: improves
- Bifidobacterium Abundance: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Appetite No effect | NoneNo effect | 43 people | ||||
| Liver Fat | Improves (the measure goes down) | 1 study | 43 people | |||
| Bifidobacterium Abundance | Improves (the measure goes up) | 43 people | ||||
| Visceral Fat | Improves (the measure goes down) | 43 people | ||||
What the published studies found
1 automated reading
LDL cholesterol
A Cochrane review (2016, 23 studies, 1,513 people) found an improvement in LDL cholesterol. That review studied adults at risk of CVD or general population. All 7 studies read agree. The evidence is moderate.
7 studies counted of 11 read: 7 reviews.
- Meta-analysis, 2016; 23 studies, 1,513 people; adults at risk of CVD or general population: improves (the review the verdict rests on).
LDL cholesterol levels (mean difference -0.14 mmol/L
Dietary fibre for the primary prevention of cardiovascular disease - Systematic review, 2026; 13 studies, 641 people; individuals with type 2 diabetes mellitus: improves.
improvements were observed in fasting glucose, HbA1c, LDL cholesterol
Impact of dietary fiber intake on insulin resistance in type 2 diabetes: A systematic review - Meta-analysis, 2024; 29 studies, 2,769 people: improves.
Compared with the control group, Plantago consumption significantly reduced total cholesterol (TC) by 0.28 mmol/L …
Plantago consumption significantly reduces total cholesterol and low-density lipoprotein cholesterol in adults: A systematic review and meta-analysis - Meta-analysis, 2023; 181 studies, 14,505 people: improves. Soluble Fiber Supplementation and Serum Lipid Profile: A Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials
- Meta-analysis, 2018; 28 studies, 1,924 people; individuals with or without hypercholesterolemia: improves.
significantly reduced LDL cholesterol (MD = -0.33 mmol/L
Effect of psyllium (Plantago ovata) fiber on LDL cholesterol and alternative lipid targets, non-HDL cholesterol and apolipoprotein B: a systematic review and meta-analysis of randomized controlled trials - Meta-analysis, 2014; 15 studies, 453 people; children and adults with familial hypercholesterolaemia: improves.
reduced total cholesterol and LDL levels
Dietary interventions (plant sterols, stanols, omega-3 fatty acids, soy protein and dietary fibers) for familial hypercholesterolaemia - Meta-analysis, 1999; 67 studies: improves.
decreases in total cholesterol [-0.045 mmol L(-1).g soluble fiber(-1) (95% CI: -0.054, -0.035)] and LDL …
Cholesterol-lowering effects of dietary fiber: a meta-analysis
- Meta-analysis, 2016; 23 studies, 1,513 people; adults at risk of CVD or general population: improves (the review the verdict rests on).
Key findings
- Blood glucoseImproves (the measure goes down)
- Glycemic ControlImproves (the measure goes up)
- High-density lipoprotein (HDL)Improves (the measure goes up)
Shop the evidence-backed picks
Third-party tested Fiber products, in the forms the graded studies used where we can match them.
- Grade B
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Studies cited
5 studies from PubMed
- The effect of high-fibre diets on glycaemic control in women with diabetes in pregnancy: A systematic review and meta-analysis.
- Does glucomannan supplementation exert profitable effects on serum lipid profile in adults? A systematic review and meta-analysis.
- Effect of soluble fiber supplementation on lipid parameters in subjects with type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials.
- Effects of Dietary Fiber Supplementation on Modulating Uremic Toxins and Inflammation in Chronic Kidney Disease Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
- Effects of different dietary patterns on glucose management in type 1 diabetes: a systematic review and meta-analysis of randomized controlled trials.