Flax and Reduced Systolic Blood Pressure

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

Across 3 studies, 2 reported small beneficial effects of flaxseed oil on systolic blood pressure (SBP), while 1 meta-analysis found no significant effect. The beneficial effects were predominantly small in size, with one randomized controlled trial showing a large reduction (-14 mmHg) in patients with metabolic syndrome. The median study duration was 49 days, and the evidence base is too small to determine a clear dose range.

Studied populations: patients with metabolic syndrome and related disorders; normotensive, prehypertensive, and hypertensive stage 1 adults

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. One meta-analysis (2024) found no significant effect, whereas two other studies (including a 2022 meta-analysis) showed significant reductions, indicating mixed signals and possible publication bias. Effects varied from small to large across studies, and the form of flax (oil vs. whole seed) was not consistently reported.

Generated Jul 13, 2026

Doses used in studies

mL/day: 25 (median 25, IQR 25–25) — 1 study

Time to effect

Median: 7 weeks · IQR 7 weeks–7 weeks · Range 7 weeks–7 weeks — Reported in 1 of 3 studies

3 of 3 papers

Supplementation of Olive Oil and Flaxseed Oil on Blood Pressure and Inflammation in Healthy and At-Risk Adults: A Systematic Literature Review and Meta-Analysis.
- 2025-01
- Meta-Analysis · n = 17
- Current hypertension reviews 20(3)
- - Tara B McNabb
  - Ian Young
  - Rachel G Newman
  - Roy C Skinner
  - Vagner A Benedito
  - Janet C Tou
- PubMed: 39558500
- DOI: 10.2174/0115734021337760241104063418
5 Insights on
- Reduced Systolic Blood Pressure
- High evidence
- Clinical
Meta-analysis using a random-effects model reported no significant effect on SBP (n=17 mean difference (MD) -0.48; 95% CI: -1.76, 0.80; p=0.65, I² =0%)
Effect
Neutral
Effect size
Small
Significant
No
The effect of flaxseed oil consumtion on blood pressure among patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized clinical trials.
- 2022-07-20
- Meta-Analysis
- Phytotherapy research : PTR 36(10)
- - Trias Mahmudiono
  - Saade Abdalkareem Jasim
  - Yasir Salam Karim
  - Dmitry Olegovich Bokov
  - Walid Kamal Abdelbasset
  - Kholmurod S Akhmedov
  - Ghulam Yasin
  - Lakshmi Thangavelu
  - Yasser Fakri Mustafa
  - Shehla Shoukat
  - Mazin A A Najm
  - Mohammad Amraei
- PubMed: 35859037
- DOI: 10.1002/ptr.7566
2 Insights on
- Reduced Systolic Blood Pressure
- High evidence
- Clinical
Meta-analysis of five trials (6 arms) showed significant reductions in systolic (WMD: -3.86 mmHg, 95% CI: -7.59 to -0.13, p = .04) BP (SBP) after flaxseed oil consumption.
Effect
Beneficial
Effect size
Small
Significant
Yes
Comparison of the effects of flaxseed oil and sunflower seed oil consumption on serum glucose, lipid profile, blood pressure, and lipid peroxidation in patients with metabolic syndrome.
- 2018-01
- RCT · n = 60
- Journal of clinical lipidology 12(1)
- - Atefeh Akrami
  - Farzad Nikaein
  - Siavash Babajafari
  - Shiva Faghih
  - Hassan Yarmohammadi
- PubMed: 29229363
- DOI: 10.1016/j.jacl.2017.11.004
9 Insights on
- Reduced Systolic Blood Pressure
- High evidence
- Clinical
between-group changes were significant (<0.05) for systolic BP (mean [±standard deviation {SD}] changes were -14.0 ± 22.41 in the FO group [P = .004] and 0.92 ± 8.70 in the SO group [P = .594])
Effect
Beneficial
Effect size
Large
Significant
Yes
Dose
25 mL/day

Flax and Reduced Systolic Blood Pressure

Supplementation of Olive Oil and Flaxseed Oil on Blood Pressure and Inflammation in Healthy and At-Risk Adults: A Systematic Literature Review and Meta-Analysis.

The effect of flaxseed oil consumtion on blood pressure among patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized clinical trials.

Comparison of the effects of flaxseed oil and sunflower seed oil consumption on serum glucose, lipid profile, blood pressure, and lipid peroxidation in patients with metabolic syndrome.