Omega-3 fats may support liver health, meta-analysis shows
Highlights
- Meta-analysis of 9 studies involving 355 adults
- Omega-3 supplementation shown to support liver fat metabolism
- Benefits seen with intakes of at least 830 mg/day, but optimal dose yet to be determined
Summary
This meta-analysis was performed to determine the effect of omega-3 fatty acid supplementation in people with non-alcoholic fatty liver disease (NAFLD) or non-alcoholic steatohepatitis (NASH). Risk factors for the development of NAFLD include central obesity, type 2 diabetes, hypertension and dyslipidemia, and prevalence in Western populations is reported to exceed 30% and be as high as 88% in obese populations.
A systematic search of the literature up to November 2010 was conducted for studies pertaining to the effect of omega-3 fatty acid supplementation in adults with NAFLD or NASH. Primary outcome measures were liver fat and liver function tests: alanine aminotransferase (ALT) and aspartate aminotransferase (AST).
Inclusion criteria included studies with oral supplementation of omega-3 fats in adults with NAFLD or NASH. Data were pooled and meta-analyses conducted using a random effects model.
Nine eligible studies involving 355 individuals given either omega-3 fatty acid supplements or control treatments were included. The median duration of supplementation with omega-3 fatty acids was 6 months (range: 8 weeks to 12 months). The median dosage was 4 g/day (range: 0.8-13.7 g/day). Significant heterogeneity between studies was reported.
Results indicate beneficial changes in liver fat with omega-3 fatty acid supplementation (effect size=-0.97, 95% CI: -0.58 to -1.35, P<.001). A benefit of omega-3 fatty acid supplementation vs. control was also observed for AST (effect size=-0.97, 95% CI: -0.13 to -1.82, P=.02). By contrast, a non-significant trend towards favoring omega-3 fatty acid supplementation on ALT was reported (effect size=-0.56, 95% CI: -1.16 to 0.03, P=.06).
In a subgroup analyses of only randomized control trials (n=4), the significant benefit for omega-3 fatty acid supplementation vs. control remained for liver fat (effect size=-0.96, 95% CI: -0.43 to -1.48, P<.001), but not for ALT (P=0.74) or AST (P=0.28).
These findings suggest that supplementation with omega-3 fatty acids (at least 830 mg/day) may offer therapeutic value for people with NAFLD or NASH; however, the optimal dosage has yet to be determined.
