Effect of Natural S-equol on Blood Pressure and Vascular funtion-a Six-month Randomized, Double-blind and Placebo-controlled Trial Among Equol Non-producers of Postmenopausal Women With Prehypertension or Untreated Stage 1 Hypertension

Inclusion criteria

1. Hong Kong Chinese women aged 45-65 y with 2~8 years menopausal;
2. Mean SBP above 130 mmHg or DBP above 80 mmHg or both based on an average of 6 BP readings on two different occasions measured by sphygmomanometer.
3. Equol non-producer is defined as 24-hour urinary log10 S-equol:daidzein ratio less than -1.75 after daidzein challenge (60mg daidzein daily for 7 consecutive days).

Exclusion criteria

1. Subjects on anti-hypertensive medication or with average SBP≥160 or DBP≥100 or both;
2. Use of medications known to affect BP within past 6 months;
3. Medical history or presence of certain chronic diseases that could affect BP or limit the individual's ability to participate in the study;
4. Present or history of certain cancers;
5. Regular smoker or alcohol consumption more than 30 g/day;
6. Known soy allergy.