rice bran and Increased HDL Cholesterol Levels

Research synthesisLow evidenceMixed effect size3 studies · 2 beneficial · 1 neutral · 0 harmful

Across 3 studies, 2 reported beneficial effects of rice bran on HDL cholesterol, with effect sizes ranging from small to large. One meta-analysis found no significant effect. Median study duration was 42 days. The evidence is mixed but promising in specific populations.

Effective dose range: Defatted rice bran (DRB)-fortified bread (3–4 slices daily) and 30 g/d of rice bran oil
Studied populations: Healthy adults with low dietary fiber intake; overweight/obese adults with metabolic syndrome

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. One large meta-analysis found no significant effect, contrasting with two smaller RCTs that reported significant benefits. Effects were observed in specific populations (low-fiber diet, metabolic syndrome) and may not generalize.

Generated May 13, 2026

Doses used in studies

g/day: 30 (median 30, IQR 30–30) — 1 study
slices/day: 3–4 (median 3.5, IQR 3–4) — 1 study

Time to effect

Median: 6 weeks · IQR 5 weeks–7 weeks · Range 4 weeks–8 weeks — Reported in 2 of 3 studies

Safety in these studies

Overall tolerabilityReported
No significant differences were observed in the primary outcome, microbial taxa composite within and between groups (False Discovery Rate (FDR) correction, p > 0.10). ... for most of the other outcomes between groups (p > 0.05).
from: Effects of defatted rice bran-fortified bread on gut microbiome, cardiovascular risk, gut

3 of 3 papersPopulation:

Effects of defatted rice bran-fortified bread on gut microbiome, cardiovascular risk, gut discomfort, wellbeing and gut physiology in healthy adults with low dietary fibre intake.
- 2025-06
- RCT · n = 15
- Clinical nutrition ESPEN 67
- - Hwei Min Ng
  - Jasjot Maggo
  - Catherine L Wall
  - Simone B Bayer
  - Jane A Mullaney
  - Diana Cabrera
  - Karl Fraser
  - Janine M Cooney
  - Catrin S Günther
  - Warren C McNabb
  - Meika Foster
  - Chris Frampton
  - Richard B Gearry
  - Nicole C Roy
- PubMed: 40127766
- DOI: 10.1016/j.clnesp.2025.03.045
15 Insights on
- Increased HDL Cholesterol Levels
- High evidence
- Adults
Only mean serum high-density lipoprotein (HDL) concentrations significantly increased (p = 0.006) in the DRB group compared to the control group.
Effect
Beneficial
Effect size
Small
Significant
Yes
Dose
Three (females) or four (males) slices of DRB-fortified bread daily
An open label randomized controlled trial of the effects of rice bran oil on cardiometabolic risk factors, lipid peroxidation and antioxidant status in overweight/obese adults with metabolic syndrome.
- 2024-08-28
- RCT · n = 50
- Lipids in health and disease 23(1)
- - Marjan Mahdavi-Roshan
  - Nargeskhatoon Shoaibinobarian
  - Mehdi Evazalipour
  - Arsalan Salari
  - Zeinab Ghorbani
  - Amir Savarrakhsh
  - Zahra Ahmadnia
- PubMed: 39198792
- DOI: 10.1186/s12944-024-02260-4
17 Insights on
- Increased HDL Cholesterol Levels
- High evidence
- Clinical
RBO consumption resulted in significantly higher levels of HDL-C (P value = 0.004; ES:0.94)
Effect
Beneficial
Effect size
Large
Significant
Yes
Dose
30 g/d
The effects of rice bran supplementation for management of blood lipids: A GRADE-assessed systematic review, dose-response meta-analysis, and meta-regression of randomized controlled trials.
- 2023-04-12
- Meta-Analysis
- Systematic reviews 12(1)
- - Zahra Hariri
  - Fatemeh Afzalzade
  - Golbon Sohrab
  - Saeede Saadati
  - Zahra Yari
- PubMed: 37046340
- DOI: 10.1186/s13643-023-02228-y
4 Insights on
- Increased HDL Cholesterol Levels
- High evidence
Meta-analysis of eight RCTs (with 11 effect sizes) showed no significant effect of rice bran supplementation on serum levels of high-density lipoprotein cholesterol (WMD: 0.16 mg/dl; 95% CI: -1.52, 1.85; P = 0.848)
Effect
Neutral
Effect size
Small
Significant
No

rice bran and Increased HDL Cholesterol Levels

Effects of defatted rice bran-fortified bread on gut microbiome, cardiovascular risk, gut discomfort, wellbeing and gut physiology in healthy adults with low dietary fibre intake.

An open label randomized controlled trial of the effects of rice bran oil on cardiometabolic risk factors, lipid peroxidation and antioxidant status in overweight/obese adults with metabolic syndrome.

The effects of rice bran supplementation for management of blood lipids: A GRADE-assessed systematic review, dose-response meta-analysis, and meta-regression of randomized controlled trials.