Safety and pharmacokinetics of purified soy isoflavones: single-dose administration to postmenopausal women.

Background: Soy isoflavones are being evaluated as chemopreventive agents for breast and other cancers.

Objective: The objective was to perform safety and pharmacokinetic studies of purified unconjugated isoflavone preparations containing genistein, daidzein, and glycitein in postmenopausal women.

Design: Twenty-four healthy postmenopausal women ingested a single dose of 1 of 2 purified (from soybeans) isoflavone preparations that delivered a genistein dose of 2, 4, 8, or 16 mg/kg body wt.

Clinical characteristics and pharmacokinetics of purified soy isoflavones: single-dose administration to healthy men.

Background: Soy isoflavones are potential cancer chemoprevention treatments.

Objective: We conducted safety studies of purified unconjugated genistein, daidzein, and glycitein, and defined pharmacokinetic parameters for their absorption and metabolism.

Design: Thirty healthy men ingested a single dose of 1 of 2 isoflavone preparations purified from soy.