n-3 polyunsaturated fatty acid supplementation reduces insulin resistance in hepatitis C virus infected patients: a randomised controlled trial

Abstract

Background: Insulin resistance promotes liver disease progression and may be associated with a lower response rate in treated hepatitis C virus (HCV) infected patients. n-3 polyunsaturated fatty acid (PUFA) supplementation may reduce insulin resistance. The present study aimed to evaluate the effect of n-3 PUFA supplementation on insulin resistance in these patients.

Methods: In a randomised, double-blind clinical trial, 154 patients were screened. After applying inclusion criteria, 52 patients [homeostasis model assessment index of insulin resistance (HOMA-IR ≥2.5)] were randomly divided into two groups: n-3 PUFA (n = 25/6000 mg day(-1) of fish oil) or control (n = 27/6000 mg day(-1) of soybean oil). Both groups were supplemented for 12 weeks and underwent monthly nutritional consultation. Biochemical tests were performed at baseline and after intervention. Statistical analysis was performed using the Wilcoxon Mann-Whitney test for comparisons and the Wilcoxon test for paired data. Statistical package r, version 3.02 (The R Project for Statistical Computing) was used and P < 0.05 (two-tailed) was considered statistically significant.

Results: Comparisons between groups showed that n-3 PUFA supplementation was more effective than the control for reducing HOMA-IR (P = 0.015) and serum insulin (P = 0.016). The n-3 PUFA group not only showed a significant reduction in HOMA-IR 3.8 (3.2-5.0) versus 2.4 (1.8-3.3) (P = 0.002); serum insulin 17.1 (13.8-20.6) μIU mL(-1) versus 10.9 (8.6-14.6) μIU mL(-1) (P = 0.001); and glycated haemoglobin 5.4% (5.0-5.7%) versus 5.1% (4.8-5.6%) (P = 0.011), but also presented an increase in interleukin-1 97.5 (0.0-199.8) pg mL(-1) versus 192.4 (102.2-266.8) pg mL(-1) (P = 0.003) and tumour necrosis factor 121.2 (0.0-171.3) pg mL(-1) versus 185.7 (98.0-246.9) pg mL(-1) (P = 0.003).

Conclusions: n-3 PUFA supplementation reduces insulin resistance in genotype 1 HCV infected patients.

Keywords: chronic hepatitis C; inflammation; insulin resistance; n-3 PUFA supplementation; nutrition.