A randomized controlled trial comparing effects of a low-energy diet with n-3 polyunsaturated fatty acid supplementation in patients with nonalcoholic fatty liver disease

Background: Weight loss is the cornerstone of NAFLD management, but weight maintenance is difficult. Some studies have suggested that n‑3 polyunsaturated fatty acid (n‑3 PUFA) might have beneficial effects in NAFLD. We aim to compare the effects of a low‑energy diet with n‑3 PUFA supplementation on liver enzymes, body composition, and cardiometabolic risk factors in NAFLD. Materials and Methods: The study was a randomized controlled trial conducted in Urmia in Iran from October 2016 to May 2017. One hundred and fourteen eligible patients were randomly assigned to one of the three following groups: low‑energy diet group, n‑3 PUFA supplementation (fish oil) group (1500 mg/d), or control group for 12 weeks. Liver enzymes, lipid profile, insulin resistance, and body composition were assessed before and after the intervention. Results: One hundred and four patients completed the study. All groups lost weight, but the reductions were greater in the diet group (−2.97 ± 2.79 kg, P = 0.001). The diet group had significant decreases in fat mass compared to other groups. Insulin resistance, total cholesterol, and low‑density lipoprotein cholesterol significantly decreased only in the diet group, and patients who lost weight ≥4% showed significantly larger decreases in serum liver enzymes. N‑3 PUFA had no beneficial effects on the study outcomes. Conclusion: We found that 1500 mg/d n‑3 PUFA supplied for 12 weeks, in contrast to 3.40 ± 2.98% weight loss, does not improve liver enzymes, body composition, and cardiometabolic risk factors in NAFLD patients.