Fish oil and liver, Non-alcoholic steatosis of the liver (NAFLD) is a condition in which more fat (5% by weight) accumulates in the liver without being due to excessive alcohol consumption. The main risk factors for the disease are metabolic syndrome, overeating and overweight, type II diabetes and others. NAFLD occurs mainly in adults, but in recent years has been diagnosed in more and more children, with a high risk in 8% of children, and in some groups the risk reaches 38%. Most medications are targeted at adults and unsuitable for children, making it imperative to look for alternative methods.
Omega-3 fatty acids, in particular DHA and EPA, have the potential to be used as a preventative for the treatment of non-alcoholic steatosis of the liver due to their effect on the genes responsible for the accumulation of fat in the liver. So far, a number of studies have been conducted on adults and children, but previous meta-analyzes and systematic reviews cover the database for adults only, with studies up to 2012. Everything is changing with a recent meta-analysis.
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Who and what is being studied?
The specific study is a meta-analysis and systematic review of all controlled randomized trials that monitor the effect of fish oil on NAFLD and metabolic outcomes in adults and children. The study was registered in PROSPERO. Only controlled studies comparing the effects of EPA and DHA with placebo are included. The main result that is observed is the percentage of fat in the liver. Secondary outcomes include hepatic edema, fibrosis, enzymes, blood lipids, fasting insulin and blood sugar, insulin sensitivity, markers of inflammation and oxidative stress, blood pressure, body composition, and omega-3 concentrations
A total of 18 studies were included, of which 14 in adults and 4 in children. Of the 14 controlled studies in adults, 12 were randomized and 9 were double-blind. The studies included 5 to 68 participants in a group with a mean age of 35 to 58 years. All four studies in children were double-blind, randomized. They include from 25 to 56 children in a group with an average age of 11 to 14 years. The doses of omega-3 used differ significantly between groups. In one study in children, only 250 mg of DHA per day from algae was used. The highest doses reached were 9 grams of fish oil per day, which included 4.62 g of EPA and 2.15 g of DHA. The duration of individual tests varies from two months to a year and a half.
What is established?
Omega-3s improve some of the markers, while others do not change. Fish oil has a positive effect on the amount of fat in the liver, reducing them by an average of 5.2%. Omega-3 significantly improves the outcome of steatosis, which is determined by image imaging. The result is seen in children and adults regardless of the dose. The result is positive in short and long studies, as well as in those of high quality and those of lower quality. Fish oil supplementation lowers the liver enzymes GGT and ALT, but not AST. Liver biopsy revealed that fish oil had no effect on fibrosis, swelling, inflammation and liver activity in NAFLD..
There is also an improvement in the lipid profile, reducing total cholesterol, “bad” cholesterol and triglycerides. In children, only an improvement in triglyceride levels is reported. Omega-3s do not improve adiponectin, blood sugar and insulin levels, but they do improve insulin sensitivity, especially in children. Omega-3s do not affect blood pressure and the percentage of subcutaneous fat in the body, but improve by a small percentage the BMI index in adults.
What exactly does the study tell us?
Omega-3 supplementation improves the metabolic results of individuals with nonalcoholic steatosis of the liver and lowers the mass of adipose tissue in the liver by a small percentage. However, omega-3 does not affect the structure of the liver itself once fibrosis has begun to manifest.
This means that the effect of omega-3 is limited to certain metabolic reactions and anti-inflammatory effect, which partially affect the development of the disease state. Omega-3s do not have a direct effect on the tissues themselves. A negative effect on the results is the fact that in these studies, which use a liver biopsy and find a minimal effect and no such effect, omega-3 doses are minimal. This means that more targeted and detailed research is needed.
Conclusion
There are several mechanisms by which the positive effect of omega-3 can be explained.
First of all, omega-3s affect certain enzymes and genes that are responsible for fat metabolism, enhance the oxidation of fat cells and reduce the synthesis of adipose tissue. This also explains the decrease in the percentage of adipose tissue in the liver.
Second, omega-3s suppress certain proteins that are responsible for lipogenic processes in the liver. Thirdly, fish oil is famous for its anti-inflammatory effect. NAFLD presents with certain pro-inflammatory metabolic problems. Fish oil has a mild anti-inflammatory effect by suppressing certain pro-inflammatory cytokines in the liver.
The present meta-analysis suggests that omega-3s may be added to NAFLD treatment, but only as an adjunct or secondary. Fish oil improves the metabolic functions of the liver, lipid profile and insulin sensitivity.
