Influence of soy isoflavone on lindane cumulant in sprague-dawley rats.

Female Sprague-Dawley rats weighing 60-80 g were given different dosages of soy isoflavones and/or lindane for four weeks. Soy isoflavones was added in feed and lindane was given by oral gavage. We found that soy isoflavones could reduce the level of lindane in rat's serum and brain, but might cause the uterus hyperplasia. Lindane could inhibit the effect of soy isoflavones on uterus and significantly decrease the level of estradiol and testosterone in serum. This study indicated that soy isoflavones could reduce the level of lindane in rat's body. Lindane could reduce the level of hormones and decreased the effect of soy isoflavones on rat's uterus.

Soy isoflavone supplementation could reduce body weight and improve glucose metabolism in non-Asian postmenopausal women--a meta-analysis.

OBJECTIVE: The objective of this study was to conduct a systematic review and a meta-analysis to confirm the effects of soy isoflavone supplementation on body weight, fasting glucose, and insulin level in non-Asian postmenopausal women. METHODS: We searched the PubMed, EMBASE, and Cochrane databases up to October 2010 for randomized controlled trials regarding the effects of isoflavone supplementation on body weight, fasting glucose, and insulin level. Pooled estimates and 95% confidence intervals (CIs) were calculated by the fixed-and-random-effects model. RESULTS: Nine studies with 528 participants for body weight, 11 studies with 1182 participants for fasting glucose, and 11 studies with 1142 participants for fasting insulin were included, respectively. Significant reductions were found in body weight [weighted mean difference (WMD), -0.515; 95%CI: -0.895 to -0.134; P = 0.008), glucose level (WMD, -0.189; 95%CI: -0.344 to -0.033), and fasting insulin level (WMD, -0.940; 95%CI: -1.721 to -0.159) with soy isoflavone supplementation compared with placebo control group in non-Asian postmenopausal women after adjusted by unpublished studies. Furthermore, isoflavone supplementation in shorter duration (<6 mo) could significantly reduce body weight (WMD, -0.506; 95%CI: -0.888 to -0.124; P = 0.009) and longer duration (≥ 6 mo) could significantly reduce blood glucose in postmenopausal women (WMD, -0.270; 95%CI: -0.430 to -0.110; P = 0.001). Meanwhile, more reduction in body weight was observed in the lower dose subgroup (dose < 100 mg). Moreover, it is more effective to reduce body weight and fasting insulin level with soy isoflavone supplementation in normal weight (body mass index < 30) than obese (body mass index ≥ 30) women. CONCLUSIONS: This meta-analysis showed soy isoflavone supplementation could be beneficial for body weight reduction, glucose, and insulin control in plasma. Large and well-designed studies are recommended to confirm this conclusion.