Fiber

Does fiber lower cholesterol?

Updated 4 Nov 2026

Short answer

Yes. Soluble fiber lowers LDL cholesterol, by a small to moderate amount. A 2023 review of 181 trials found a fall of 8.28 mg/dL, and each extra 5 g a day added about 5.57 mg/dL.[1] A Cochrane review found that its trials were too short to show whether this means fewer heart attacks.[2]

What the reviews found

LDL cholesterol is a blood fat. Lowering it decreases the risk of coronary heart disease, according to EFSA, the EU food safety authority.[3] Each result below compares fiber with a control diet or placebo:

  • All soluble fibers. 181 trials, 14,505 people: LDL 8.28 mg/dL (about 0.21 mmol/L) lower and total cholesterol 10.82 mg/dL lower.[1]
  • Psyllium. 28 trials, 1,924 people, a median of about 10.2 g a day: LDL 0.33 mmol/L (about 13 mg/dL) lower, graded moderate quality.[4]
  • Oat beta-glucan. 58 trials, 3,974 people, a median of 3.5 g a day: LDL 0.19 mmol/L lower, with large differences between trials that the authors could not explain.[5]
  • Barley beta-glucan. 14 trials, 615 people, a median of 6.5 g a day for 4 weeks: LDL 0.25 mmol/L lower.[6]
  • Konjac glucomannan. 12 trials, 370 people, about 3 g a day: LDL 0.35 mmol/L lower, or about 10%.[7]

A 2021 overview of 108 systematic reviews rated the evidence as high for foods rich in soluble fiber, such as oats, barley and psyllium, with falls of 0.20 to 0.40 mmol/L.[8]

Older and broader reviews found less. A 1999 review of 67 trials called the effect small within the practical range of intake: 3 g of soluble fiber from oats lowered LDL by about 0.13 mmol/L.[9] A 2016 Cochrane review of 23 trials of many fiber types found LDL 0.14 mmol/L lower, with an unclear risk of bias in most trials.[2]

What single trials found

In 340 UK patients with mild to moderate high cholesterol, 7 g and 10.5 g of psyllium husk a day lowered LDL by 8.7% and 9.7% after 12 weeks, more than placebo.[10] In 367 adults, 3 g of oat beta-glucan a day lowered LDL by about 5% in 4 weeks.[11] The European Medicines Agency (EMA) reports about 7% for psyllium husk in mild to moderate high cholesterol.[12]

HDL and triglycerides

Fiber does not raise HDL cholesterol. Two reviews found no change, and the Cochrane review found a very small fall of 0.03 mmol/L.[9][13][2] Results on triglycerides differ. The 2023 review found 5.55 mg/dL lower, and three other reviews found no change.[1][9][13][2]

Why it may work

  1. Soluble fiber forms a gel in the gut and binds bile acids, so more of them leave in stool.[14]
  2. The liver makes bile acids from cholesterol, so it may use more cholesterol to replace them.[15]
  3. The liver may then take more LDL cholesterol from the blood.[15]

Parts of this come from animal studies, and some work on guar gum questions the older view of bile acid uptake.[15] A role for propionate, a product of fermentation, has not been shown.[14]

What is still unknown

None of the 23 trials in the Cochrane review reported deaths or heart events, because they were short.[2] The EMA also says that no studies of psyllium husk measured these outcomes.[12] A 2024 review estimated about 7% fewer heart events from the LDL fall with Plantago, the psyllium plant, but this is a calculation and was not measured.[13] Observational studies link high fiber intake from food with less heart disease. Their authors think the link could be causal, but these studies did not test supplements.[16]

Who should be careful

The EMA says that using psyllium husk for high cholesterol needs medical supervision.[12] A small trial gave fiber together with a statin, and LDL fell further.[17] Which fiber lowers cholesterol the most is not settled: a 1999 review found no significant difference between soluble fiber from oats, psyllium and pectin.[9]

Sources (17)

  1. Soluble Fiber Supplementation and Serum Lipid Profile: A Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials. Ghavami A, Ziaei R, Talebi S, Barghchi H, Nattagh-Eshtivani E, Moradi S, et al. Adv Nutr, 2023. PMID 36796439
  2. Dietary fibre for the primary prevention of cardiovascular disease. Hartley L, May MD, Loveman E, Colquitt JL, Rees K Cochrane Database Syst Rev, 2016. PMID 26758499
  3. Scientific Opinion on the substantiation of a health claim related to oat beta glucan and lowering blood cholesterol and reduced risk of (coronary) heart disease. European Food Safety Authority, 2010. efsa.onlinelibrary.wiley.com
  4. 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. Jovanovski E, Yashpal S, Komishon A, Zurbau A, Blanco Mejia S, Ho HVT, et al. Am J Clin Nutr, 2018. PMID 30239559
  5. The effect of oat β-glucan on LDL-cholesterol, non-HDL-cholesterol and apoB for CVD risk reduction: a systematic review and meta-analysis of randomised-controlled trials. Ho HV, Sievenpiper JL, Zurbau A, Blanco Mejia S, Jovanovski E, Au-Yeung F, et al. Br J Nutr, 2016. PMID 27724985
  6. A systematic review and meta-analysis of randomized controlled trials of the effect of barley β-glucan on LDL-C, non-HDL-C and apoB for cardiovascular disease risk reduction(i-iv). Ho HV, Sievenpiper JL, Zurbau A, Blanco Mejia S, Jovanovski E, Au-Yeung F, et al. Eur J Clin Nutr, 2016. PMID 27273067
  7. A systematic review and meta-analysis of randomized controlled trials of the effect of konjac glucomannan, a viscous soluble fiber, on LDL cholesterol and the new lipid targets non-HDL cholesterol and apolipoprotein B. Ho HVT, Jovanovski E, Zurbau A, Blanco Mejia S, Sievenpiper JL, Au-Yeung F, et al. Am J Clin Nutr, 2017. PMID 28356275
  8. The effects of foods on LDL cholesterol levels: A systematic review of the accumulated evidence from systematic reviews and meta-analyses of randomized controlled trials. Schoeneck M, Iggman D Nutr Metab Cardiovasc Dis, 2021. PMID 33762150
  9. Cholesterol-lowering effects of dietary fiber: a meta-analysis. Brown L, Rosner B, Willett WW, Sacks FM Am J Clin Nutr, 1999. PMID 9925120
  10. Ispaghula husk in the treatment of hypercholesterolaemia: a double-blind controlled study. MacMahon M, Carless J J Cardiovasc Risk, 1998. PMID 10201553
  11. Physicochemical properties of oat β-glucan influence its ability to reduce serum LDL cholesterol in humans: a randomized clinical trial. Wolever TM, Tosh SM, Gibbs AL, Brand-Miller J, Duncan AM, Hart V, et al. Am J Clin Nutr, 2010. PMID 20660224
  12. Community herbal monograph on Plantago ovata Forssk., seminis tegumentum. European Medicines Agency, HMPC, 2013. www.ema.europa.eu
  13. Plantago consumption significantly reduces total cholesterol and low-density lipoprotein cholesterol in adults: A systematic review and meta-analysis. Zhu R, Lei Y, Wang S, Zhang J, Mengjiao Lv, Jiang R, et al. Nutr Res, 2024. PMID 38688104
  14. Mechanisms underlying the cholesterol-lowering properties of soluble dietary fibre polysaccharides. Gunness P, Gidley MJ Food Funct, 2010. PMID 21776465
  15. Guar gum and similar soluble fibers in the regulation of cholesterol metabolism: current understandings and future research priorities. Rideout TC, Harding SV, Jones PJ, Fan MZ Vasc Health Risk Manag, 2008. PMID 19183750
  16. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L Lancet, 2019. PMID 30638909
  17. Effect of combining psyllium fiber with simvastatin in lowering cholesterol. Moreyra AE, Wilson AC, Koraym A Arch Intern Med, 2005. PMID 15911730

More about fiber

What is fiber?How does fiber lower cholesterol?How much fiber do you need per day?What is fiber used for?How long does fiber take to lower cholesterol?Is fiber safe?

For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.