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 single-blinded 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), gamma 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 x 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 x ULN and visceral fat were predictors of an HOMA-IR >= 3. The IG group had a reduced risk of an ALT level > 1.5 x 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. (C) 2012 Baishideng. All rights reserved.