Effect of synbiotic fermented milk on oral bioavailability of isoflavones in postmenopausal women.

The purpose of this study was to investigate the effect of synbiotic fermented milk, containing Lactobacillus paracasei and inulin, on oral bioavailability and pharmacokinetics of isoflavones in healthy postmenopausal women. The study was a one-group pre-post treatment study. Twelve subjects were assigned to consume a single oral dose of 375 mL of soy beverage. Blood samples were collected immediately before and at various time points until 32 hours after the administration of the soy beverage. After a washout period, subjects were requested to consume 180 mL of synbiotic fermented milk after breakfast and dinner for 14 days, followed by a single oral dose of 375 mL of soy beverage on the next day. Collection of blood samples after the administration of the soy beverage were performed at the same time points as the former phase. Plasma isoflavone concentrations were measured by using high-performance liquid chromatography (HPLC) technique. In conclusion, this study highlighted that continuous consumption of synbiotic fermented milk followed by a single oral administration of soy beverage significantly enhanced oral bioavailability of isoflavones compared with a single oral dose of soy beverage alone.