The investigators hypothesize that whole soy or purified daidzein alone could reduce blood pressure and CVD risks in equol-producing menopausal Chinese women.

Hypertension is an important risk factor for cardiovascular diseases. Substantial evidence has also shown that prehypertension [systolic blood pressure (BP) 120-139 mm Hg or diastolic BP 80-89 mm Hg] is the strongest predictor of incident hypertension and is associated with elevated risk of cardiovascular diseases. Thus, prehypertension and its progression to hypertension have enormous public health implications. Soybean contains many beneficial components, among which isoflavones have received most research attention. Recently researchers have investigated their influences on vascular functions but only a handful of studies have focused on BP reduction as the primary outcome.The role of whole soy or daidzein on BP is yet unclear.

The investigators hypothesize that whole soy (soy flour) or purified daidzein alone could reduce BP,and decrease CVD risks in menopausal women with prehypertension or initial untreated hypertension. The investigators propose to perform a 24-week double-blind, randomized, placebo-controlled trial in postmenopausal women with prehypertension or stage 1 hypertension. The primary objective is to verify if whole soy (soy flour) or purified daidzein alone has anti-hypertensive effects at a dosage of habitual high soy intake.

Inclusion Criteria:

• Postmenopausal Chinese women with prehypertension or stage 1 hypertension

Exclusion Criteria:

• Medical treatment for blood pressure or lipids reduction hormones replacement therapy in recent 3 months, chronic renal or hepatic diseases