The aim of this study is to investigate the effects of gut microbial metabolism of flaxseed lignans on cardiovascular health. Enterolactone is the main gut microbial metabolite of lignans. The study population will be stratified in low and high enterolactone producers and will investigate whether high producers will have greater benefits than low producers, and whether low producers may become high producers after daily consumption of lignans over 8 weeks. The investigators will evaluate changes in endothelial function, blood pressure, arterial stiffness, insulin resistance, lipid profile and gut microbiome composition after 8 weeks daily consumption of flaxseed lignans.

Epidemiological studies have shown inverse relation between enterolactone levels and cardiovascular mortality. Participants will be stratified from first phase (NCT03573414) and then randomly allocated to treatment or placebo. Outcomes are measured at baseline and after 8 weeks post consumption.

Inclusion Criteria:

• Healthy women aged 20-70 years
• BMI between 18 and 35 kg/m2
• Subjects are willing to maintain their normal eating/drinking habits and exercise habits to avoid changes in body weight over the duration of the study
• Are able to understand the nature of the study
• Able to give signed written informed consent
• Signed informed consent form

Exclusion Criteria:

• Medical history of cardiovascular disease including coronary artery disease, cerebrovascular disease and peripheral artery disease
• Hypertensive, as defined as SBP superior or equal to 140 mmHg, and CBP superior or equal to 90 mmHg
• Participants with BMI superior to 35 kg/m2, and BMI below 18 kg/m2
• Medical history of diabetes mellitus, metabolic syndrome, terminal renal failure or malignancies
• Abnormal heart rhythm (lower or higher than 60-100 bmp)
• Allergies to flaxseed or other significant food allergy
• Subjects under medication that can affect the cardiovascular system or on vitamin/dietary supplements.
• Subjects who have lost more than 10% of their weight in the past 6 months or are currently in a diet
• Subjects who reported participant in another study within one month before the study start
• Smoker Subjects
• Pregnant women or planning to become pregnant in the next 6 months
• Any reason or condition that in the judgment of the clinical investigator(s) may put the subject at unacceptable risk or that may preclude the subject from understanding or complying with the study's requirements.