flaxseed and Reduced High-Density Lipoprotein Cholesterol Level

Research synthesisLow evidenceSmall effect3 studies · 0 beneficial · 2 neutral · 1 harmful

Across 3 meta-analyses, flaxseed supplementation shows no evidence of reducing HDL cholesterol. Two studies reported neutral effects (small effect size), while one study found a small harmful effect (statistically significant decrease) in postmenopausal women. The predominant effect size is small, and no consistent dose or form data were reported.

Studied populations: clinical populations (type 2 diabetes, coronary artery disease, postmenopausal women)

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. The only statistically significant finding was a small reduction in HDL in postmenopausal women, suggesting the effect may be population-specific.

Generated Jul 10, 2026

3 of 3 papersPopulation:

The effect of flaxseed supplementation on anthropometric indices, blood pressure, and lipid profile in diabetic patients: A GRADE-assessed systematic review and meta-analysis of randomized controlled trials.
- 2025-05
- Meta-Analysis · n = 1,136
- Diabetes & metabolic syndrome 19(5)
- - Vali Musazadeh
  - Shokufeh Nezamoleslami
  - Amir Hossein Faghfouri
  - Farzad Shidfar
  - Naheed Aryaeian
- PubMed: 40499336
- DOI: 10.1016/j.dsx.2025.103241
9 Insights on
- Reduced High-Density Lipoprotein Cholesterol Level
- High evidence
- Clinical
high-density lipoprotein cholesterol (SMD: 0.08; 95% CI: 0.30 to 0.46, p = 0.673)
Effect
Neutral
Effect size
Small
Significant
No
Role of Phytoestrogen-Rich Bioactive Substances (Linum usitatissimum L., Glycine max L., Trifolium pratense L.) in Cardiovascular Disease Prevention in Postmenopausal Women: A Systematic Review and Meta-Analysis.
- 2022-06-14
- Meta-Analysis
- Nutrients 14(12)
- - Agata Błaszczuk
  - Agnieszka Barańska
  - Wiesław Kanadys
  - Maria Malm
  - Monika Elżbieta Jach
  - Urszula Religioni
  - Rafał Wróbel
  - Jolanta Herda
  - Małgorzata Polz-Dacewicz
- PubMed: 35745197
- DOI: 10.3390/nu14122467
4 Insights on
- Reduced High-Density Lipoprotein Cholesterol Level
- High evidence
- Rigorous Journal
- Elderly
high-density lipoprotein cholesterol (HDL-C) levels (WMD = -0.06; 95% CI: -0.11 to -0.01; p = 0.0150)
Effect
Harmful
Effect size
Small
Significant
Yes
Effects of flaxseed supplementation on weight loss, lipid profiles, glucose, and high-sensitivity C-reactive protein in patients with coronary artery disease: A systematic review and meta-analysis of randomized controlled trials.
- 2024-01
- Meta-Analysis
- Clinical cardiology 47(1)
- - Hamid Reza Sabet
  - Mohammad Ahmadi
  - Mehdi Akrami
  - Mahsa Motamed
  - Omid Keshavarzian
  - Mozhan Abdollahi
  - Mehdi Rezaei
  - Hamed Akbari
- PubMed: 38269632
- DOI: 10.1002/clc.24211
8 Insights on
- Reduced High-Density Lipoprotein Cholesterol Level
- High evidence
- Clinical
The pooled results did not show significant changes in the WMD of lipid factors (high-density lipoprotein cholesterol, triglycerides (TG), low-density lipoprotein cholesterol, and total cholesterol) following flaxseed intake.
Effect
Neutral
Effect size
Small
Significant
No

flaxseed and Reduced High-Density Lipoprotein Cholesterol Level

The effect of flaxseed supplementation on anthropometric indices, blood pressure, and lipid profile in diabetic patients: A GRADE-assessed systematic review and meta-analysis of randomized controlled trials.

Role of Phytoestrogen-Rich Bioactive Substances (Linum usitatissimum L., Glycine max L., Trifolium pratense L.) in Cardiovascular Disease Prevention in Postmenopausal Women: A Systematic Review and Meta-Analysis.

Effects of flaxseed supplementation on weight loss, lipid profiles, glucose, and high-sensitivity C-reactive protein in patients with coronary artery disease: A systematic review and meta-analysis of randomized controlled trials.