Effect of Soy Isoflavone Crude Extract Supplementation on High Fat Diet-induced Insulin Resistance in Ovariectomized Rats

Female Wister rats aged 8 weeks were randomly divided into sham operation group, ovariectomized （OVX） control group, and 20VX groups fed with soy isoflavone crude extract supplementation. The rats had free access to high fat diet and water for 9 weeks. No significant difference was found in body weight （BW）, total abdominal fat, food intake and food utilization rate between OVX control group and 20VX groups. However, the fasting blood glucose and blood lipid levels were significantly higher in 20VX groups than in OVX control group （P〈0.05）. Intraperitoneal glucose tolerance test （IGTI＂） showed that the area under AUC was smaller in 20VX groups than in OVX control group （P〈0.05）. These findings showed that soy isoflavone crude extract supplementation can improve glucose tolerance and prevent high fat diet-induced insulin resistance in ovariectomized rats.

Effect of soy protein supplementation in patients with chronic hepatitis C:A randomized clinical trial

AIM:To evaluate the effects of soy supplementation on insulin resistance,fatty liver and alanine aminotransferase(ALT) levels in non-diabetic patients with chronic hepatitis C(CHC).METHODS:In a prospective,randomized and singleblinded clinical trial,we compared patients with CHC who had casein as a supplement(n = 80)(control group),with patients who consumed a soy supplement diet(n = 80) [intervention group(IG)].Both groups received 32 g/d of protein for 12 wk.RESULTS:Patients' baseline features showed that 48.1% were overweight,43.7% had abdominal fat accumulation,34.7% had hepatic steatosis and 36.3% had an homeostasis model assessment index of insulin resistance(HOMA-IR) ≥ 3.0.Descriptive analysis showed that protein supplementation diet reduced hepatic steatosis in both groups;however,significant reductions in ALT levels occurred in the soy group.Multiple regression modeling indicated that in the presence of severe fibrosis(F3/F4),g glutamyl transferase elevation and high density lipoprotein(HDL) reduction,the intervention group had 75% less chance of developing hepatic steatosis(OR= 0.25;95% CI:0.06-0.82) and 55% less chance of presenting with an ALT level ≥ 1.5 × the upper limit of normal(ULN)(OR = 0.45,95% CI:0.22-0.89).Soy treatment did not have any effect on insulin resistance(OR = 1.92;95% CI:0.80-4.83),which might be attributed to the fact that the HOMAIR values at baseline in most of our patients were in the normal range.Advanced hepatic fibrosis,an ALT level > 1.5 × ULN and visceral fat were predictors of an HOMA-IR ≥ 3.The IG group had a reduced risk of an ALT level > 1.5 × ULN.An HOMA-IR ≥ 3.0 and HDL < 35 mg/dL were also risk factors for increased ALT.CONCLUSION:Soy supplementation decreased ALT levels and thus may improve liver inflammation in hepatitis C virus(HCV) patients;it also reduced hepatic steatosis in a subgroup of patients but did not change insulin resistance.It should be considered in the nutritional care of HCV patients.