Research synthesisLow evidenceMixed effect size4 studies · 2 beneficial · 2 neutral · 0 harmful
Across 4 studies, 2 reported beneficial effects of flaxseed supplementation on reduced body weight, with 2 showing neutral results. The largest and highest-quality study—a meta-analysis of 1,136 participants with type 2 diabetes—found a large, statistically significant benefit (SMD: 0.81; p = 0.028). The predominant effect size is mixed (small to large), and effects were typically observed at 8 weeks (median study duration: 56 days). Most evidence comes from clinical populations, particularly people with type 2 diabetes or coronary artery disease.
- Effective dose range: ≥ 30 g/day for at least 12 weeks
- Studied populations: people with type 2 diabetes, patients with coronary artery disease
Caveats: Evidence base is small (only 4 studies) — conclusions should be considered preliminary. The two neutral studies (including an RCT and a meta-analysis) did not reach statistical significance, and one meta-analysis in CAD patients found no effect on weight. The beneficial meta-analysis in type 2 diabetes reports limited generalizability, and the only review suggesting benefit scored low on evidence quality (score of 1).
Generated Jul 10, 2026