Lignans (Flaxseed Lignans)
Research reviewed: Up until 03/2026
Lignans (Flaxseed Lignans) (Secoisolariciresinol Diglucoside / Enterolignans) is a dietary supplement with 9 published peer-reviewed studies involving 1,450 participants, researched for Menopause Symptoms, Cardiovascular Health, Breast Health and 1 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Menopause Symptoms
ModerateCardiovascular Health
StrongBreast Health
ModerateBlood Sugar Control
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Menopause Symptoms
To evaluate flaxseed supplementation on hot flush frequency and severity in postmenopausal women
Study Type
Randomised double-blind placebo-controlled trial
Purpose
To evaluate flaxseed supplementation on hot flush frequency and severity in postmenopausal women
Dose
40 g ground flaxseed daily (~50 mg SDG)
Participants
188 postmenopausal women with hot flushes
Duration
6 weeks
Results
Flaxseed supplementation significantly reduced hot flush frequency (−4.9 vs −3.5 per day) and composite hot flush score compared to wheat germ placebo. No significant difference in adverse events between groups.
How They Measured It
Hot flush diary (frequency and severity), MENQOL, urinary enterolactone
To evaluate flaxseed and lignans for menopausal symptom relief
Study Type
Systematic review
Purpose
To evaluate flaxseed and lignans for menopausal symptom relief
Dose
Flaxseed supplement (20-40 g/day) or purified SDG
Participants
Review of 6 RCTs
Duration
Various
Results
Flaxseed and lignan supplementation produced modest but significant reductions in hot flush frequency and severity. Evidence for other menopausal symptoms (mood, sleep, vaginal dryness) is limited. Well tolerated.
How They Measured It
Systematic review of clinical trials
Cardiovascular Health
To evaluate flaxseed lignan supplementation on lipid profiles in dyslipidaemic adults
Study Type
Randomised double-blind placebo-controlled trial
Purpose
To evaluate flaxseed lignan supplementation on lipid profiles in dyslipidaemic adults
Dose
600 mg SDG daily (flaxseed lignan)
Participants
55 adults with dyslipidemia
Duration
8 weeks
Results
Flaxseed lignan supplementation significantly reduced LDL cholesterol (−14.7%), total cholesterol (−9.7%), ApoB, and hs-CRP compared to placebo. HDL and triglycerides were unchanged. Well tolerated.
How They Measured It
Total cholesterol, LDL, HDL, triglycerides, ApoB, hs-CRP
To determine the effect of flaxseed lignans on lipid profiles across controlled trials
Study Type
Meta-analysis
Purpose
To determine the effect of flaxseed lignans on lipid profiles across controlled trials
Dose
Flaxseed or purified SDG supplements
Participants
Meta-analysis of 11 RCTs (n=607)
Duration
Various
Results
Flaxseed lignans significantly reduced total cholesterol (−0.10 mmol/L) and LDL (−0.08 mmol/L) cholesterol. Greater effects observed with whole flaxseed vs purified lignans, suggesting synergistic effects of fiber and lignans.
How They Measured It
Meta-analysis of lipid outcomes from RCTs
Breast Health
To evaluate flaxseed consumption on breast cancer biomarkers in postmenopausal women with newly diagnosed breast cancer
Study Type
Randomised double-blind placebo-controlled trial
Purpose
To evaluate flaxseed consumption on breast cancer biomarkers in postmenopausal women with newly diagnosed breast cancer
Dose
25 g ground flaxseed daily
Participants
32 postmenopausal women with newly diagnosed breast cancer (pre-surgery)
Duration
Mean 39 days until surgery
Results
Flaxseed supplementation significantly reduced tumor Ki67 proliferation index (−34.2%), increased apoptosis, and reduced c-erbB2 expression in tumor tissue. Significantly favorable effects on breast cancer biomarkers observed.
How They Measured It
Ki67 tumor proliferation marker, apoptosis (TUNEL), HER2 expression, tumor size at surgery
To examine the association between lignan intake and breast cancer risk and mortality
Study Type
Prospective cohort study
Purpose
To examine the association between lignan intake and breast cancer risk and mortality
Dose
Dietary lignan intake (SDG equivalents)
Participants
Prospective cohort of 2,820 breast cancer survivors (mean follow-up 6.4 years)
Duration
6.4 years
Results
Higher post-diagnosis dietary lignan intake was associated with a 40% reduction in breast cancer mortality (HR 0.60, 95% CI 0.40-0.91) and 33% reduction in all-cause mortality. Urinary enterolactone levels confirmed this association.
How They Measured It
Breast cancer incidence, breast cancer mortality, urinary enterolactone levels
Blood Sugar Control
To evaluate flaxseed lignan supplementation on glycemic control in patients with type 2 diabetes
Study Type
Randomised double-blind placebo-controlled trial
Purpose
To evaluate flaxseed lignan supplementation on glycemic control in patients with type 2 diabetes
Dose
360 mg SDG daily
Participants
60 adults with type 2 diabetes
Duration
12 weeks
Results
Flaxseed lignan supplementation significantly reduced fasting glucose (−19.7 mg/dL), HbA1c (−0.5%), and HOMA-IR compared to placebo. Cholesterol and triglyceride levels also significantly improved. Well tolerated.
How They Measured It
Fasting glucose, HbA1c, fasting insulin, HOMA-IR, lipid panel
To investigate the mechanisms by which SDG improves glucose metabolism in diabetic rats
Study Type
Animal study
Purpose
To investigate the mechanisms by which SDG improves glucose metabolism in diabetic rats
Dose
50-150 mg/kg SDG
Participants
24 STZ-induced diabetic rats
Duration
8 weeks
Results
SDG significantly reduced fasting glucose, improved glucose tolerance, enhanced GLUT4 expression in muscle, stimulated glucokinase activity in liver, and reduced hepatic oxidative stress and insulin resistance.
How They Measured It
GLUT4 expression, insulin receptor signaling, glucose uptake, glucokinase activity, antioxidant status
To comprehensively evaluate the health effects of flaxseed lignans and their enterolignan metabolites
Study Type
Systematic review
Purpose
To comprehensively evaluate the health effects of flaxseed lignans and their enterolignan metabolites
Dose
Flaxseed and SDG formulations
Participants
Review of 35 clinical and epidemiological studies
Duration
Various
Results
Flaxseed lignans converted to enterolactone/enterodiol by gut bacteria show consistent benefits for cardiovascular health, glycemic control, and breast cancer outcomes. Enterolactone levels are critical mediators of effects.
How They Measured It
Systematic review of RCTs and observational studies on cardiovascular, metabolic, and cancer endpoints
Frequently Asked Questions
Common questions about Lignans (Flaxseed Lignans) research
There are currently 9 peer-reviewed studies on Lignans (Flaxseed Lignans) (Secoisolariciresinol Diglucoside / Enterolignans), involving 1,450 total participants. Research covers Menopause symptoms, Cardiovascular health, Breast health and 1 more areas. The overall evidence strength is rated as Very Strong.
The evidence is currently rated as "Very Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (9 human studies), and reported outcomes.
Lignans (Flaxseed Lignans) has been researched for: Menopause symptoms, Cardiovascular health, Breast health, Blood sugar control. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 9 out of 9 studies are human trials. Human trials carry more weight in our evidence scoring system.
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