Effects of Omega-3 Polyunsaturated Fatty Acid Supplementation on Non-Alcoholic Fatty Liver: A Systematic Review and Meta-Analysis

Abstract

(1) Aim: Non-alcoholic fatty liver disease (NAFLD) is a prevalent disease worldwide. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) bear anti-inflammatory action and can ameliorate hyperlipidemia. We wish to appraise the effects of n-3 PUFAs supplement on NAFLD. (2) Methods: We searched CENTRAL, Embase, and MEDLINE on 29 March 2020 for randomized control trials (RCTs) on the effects of n-3 PUFAs supplementation in treating NAFLD. The Cochrane Collaboration’s tool was used to assess the risk of bias of included RCTs. (3) Results: We included 22 RCTs with 1366 participants. The risk of bias of included RCTs was generally low or unclear. n-3 PUFAs supplementation significantly reduced liver fat compared with placebo (pooled risk ratio 1.52; 95% confidence interval (CI) 1.09 to 2.13). n-3 PUFAs supplementation also significantly improved the levels of triglyceride, total cholesterol, high-density lipoprotein, and body-mass index, with pooled mean difference and 95% CI being −28.57 (−40.81 to −16.33), −7.82 (−14.86 to −0.79), 3.55 (1.38 to 5.73), and −0.46 (−0.84 to −0.08), respectively. (4) Conclusions: The current evidence supports the effects of n-3 PUFAs supplementation in improving fatty liver. n-3 PUFAs supplementation may also improve blood lipid levels and obesity.

Overview of Non-Alcoholic Fatty Liver Disease (NAFLD) and the Role of Sugary Food Consumption and Other Dietary Components in Its Development

“…In fact, many systematic reviews and meta-analyses of randomised controlled trials have addressed the topic of Omega-3 supplementation and its effect on patients suffering from NAFLD. These studies conclude that Omega 3 PUFAs supplementation (>3 g/day) is useful for the reduction of liver fat, hepatic enzymes, BMI, triglycerides, and cholesterol [ 115 , 116 ]. This potentially sets Omega-3 food supplementation as a safe, viable, and effective intervention to help treat NAFLD.…”

Treatments for NAFLD: State of Art

“…Omega-3 polyunsaturated fatty acids (n-3 PUFAs) contain several long chain fatty acids, such as α-linolenic acid (α-ALA), stearidonic acid (SDA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) [ 115 ]. EPA and DHA decrease the levels of triglyceride and very-low-density lipoproteins, which are converted to low-density lipoprotein and intermediate-density lipoprotein [ 115 ]. Accumulating evidence also suggests that dietary n −3 PUFAs could improve insulin resistance by regulating mitochondrial function and mediating anti-inflammatory effects [ 115 ].…”

“…EPA and DHA decrease the levels of triglyceride and very-low-density lipoproteins, which are converted to low-density lipoprotein and intermediate-density lipoprotein [ 115 ]. Accumulating evidence also suggests that dietary n −3 PUFAs could improve insulin resistance by regulating mitochondrial function and mediating anti-inflammatory effects [ 115 ]. Several preclinical studies using animal NASH models have suggested that the supplementation of n −3 PUFAs could exert a positive impact on NAFLD by diminishing hepatic fat deposition and preventing the proinflammatory state [ 116 ].…”

“…In a 2020 meta-analysis of 22 RCTs with a total of 1366 participants with and without T2DM, Lee et al reported that n −3 PUFAs supplementation significantly reduced liver fat (evaluated by imaging methods) when compared with placebo (pooled risk ratio 1.52, 95% confidence interval 1.09–2.13) [ 115 ]. In that study, in addition, n −3 PUFAs supplementation significantly improved the levels of triglyceride, total cholesterol, high-density lipoprotein, and BMI [ 115 ]. Similar findings were also observed in another meta-analysis [ 117 ].…”

Omega 3 fatty acids effect on the vascular calcification biomarkers fetuin A and osteoprotegerin in hemodialysis patients

“…Recent study suggested that omega-3 fatty acids, a group of polyunsaturated fatty acids (PUFAs), have a positive effect in the treatment of different renal diseases such as diabetic nephropathy and cyclosporine nephrotoxicity [20]. In patients with NAFLD, studies showed that omega-3 may help in decrease liver fat, improving fatty liver and may also improve blood lipid levels and obesity [21]. Moreover, eicosapentaenoic acid (EPA) supplementation enhanced the cognitive function and was superior to docosahexaenoic acid (DHA) [22].…”