Daidzein and genistein fail to improve glycemic control and insulin sensitivity in Chinese women with impaired glucose regulation: A double-blind, randomized, placebo-controlled trial

Scope: This randomized, double-blind, and placebo-controlled trial evaluated the effect of isolated daidzein and genistein on glycemic control and insulin sensitivity in 165 Chinese women aged 30-70 with impaired glucose regulation (IGR). Methods and results: Participants were randomly assigned to one of three groups with a daily dose of 10 g of soy protein plus (i) no addition, (ii) 50 mg of daidzein, or (iii) 50 mg of genistein for 24 wk. Fasting glucose (FG), insulin, and glycosylated hemoglobin (HbA(1c)), and glucose concentrations at 30, 60, 120, and 180 min and insulin concentrations at 30, 60, and 120 min after an oral 75-g glucose tolerance test were assessed at baseline and at 12 and 24 wk postintervention. a total of 158 and 151 subjects completed the measures at wk 12 and 24, respectively. There were no significant differences in the changes (%) of FG and the 2-h glucose, HbA1c, fasting, and 2-h insulin or the area under the curve of glucose and insulin between the three treatment groups at wk 12 or 24 (all p > 0.05). Conclusion: Neither isolated daidzein nor genistein has a significant effect on glycemic control and insulin sensitivity in Chinese women with IGR over a 6-month supplementation period.