In patients with Nonalcoholic Hepatic Steatosis, supplementation with 4 grams of omega-3 can improve hepatic lipid metabolism. Specifically, an increase of at least 2% in the concentration of DHA in red blood cells, as an effect of consuming omega-3 supplements, is associated with a significant reduction in fat deposited in the liver and improved insulin sensitivity by the organ.

This was discovered by researchers at Oxford, Southampton and Surrey Universities (UK), and published in the European Journal of Clinical Nutrition.

Fatty liver, a widespread problem in Western countries

Hepatic steatosis is a cellular pathology related to the accumulation in liver cells of triglycerides that reach more than 5-10% of the weight of the organ itself. The pathology can be caused by increased fat intake, reduced fat disposal, or increased fat synthesis.

• Steatosis due to excessive fat intake can be caused by a diet too rich in lipids or by increased mobilization of fatty acids. The latter in turn can be caused by factors such as stress, hormones, prolonged fasting, and diabetes.
• Steatosis from reduced fat disposal may be due to a hypoprotein diet, decreased apolipoprotein synthesis, and vitamin B12 deficiency.
• Steatosis from increased lipid synthesis is due to an accumulation of endogenously synthesized fats and can be caused by certain drugs or alcohol abuse.

Non-Alcoholic Hepatic Steatosis (NAFLD) encompasses a group of liver diseases, ranging from what is commonly called fatty liver, to NASH (Non-Alcoholic Steatohepatitis) characterized by a condition in which the liver is subject to inflammatory processes, scarring and tissue death, to cirrhosis the most advanced stage of the disease. Experts consider NAFLD to be the liver-level manifestation of the metabolic syndrome. The prevalence of NAFLD in Western countries is probably due to the spread of overweight and obesity, insulin resistance, diabetes, and high cholesterol. Fatty liver may even be present in children (10% of cases) especially those who are obese. In case of Non-Alcoholic Hepatic Steatosis, it is therefore important to follow some tips:

• Lose weight if you are obese or overweight
• follow a healthy and balanced diet
• work out
• avoid alcoholic beverages
• avoid drugs unless strictly necessary
  

As is well known, omega-3 fatty acids in high doses can reduce plasma triglyceride concentrations. Several studies have reported how omega-3s can reduce liver fat and that short-term treatment with these fatty acids improves whole-body insulin sensitivity. However, the effects of supplementation with EPA and DHA on insulin sensitivity in the context of NAFLD remain unclear.

L'omega-3 supplementation increases DHA in the globured blood cells and reduces fat in the liver

The purpose of this new study was to test whether an increase in DHA in red blood cells was associated with changes in the signal molecules of Non-Alcoholic Hepatic Steatosis. In this regard, the researchers monitored the effect of supplementation with high doses of omega-3 (about 4 grams per day). The results showed, following supplementation, an improvement in fatty acid oxidation and liver sensitivity to insulin. The latter as is known promotes the entry of glucose into the body's sensitive tissues, i.e., muscle, liver and adipose tissue. According to research results, moreover, the supplements also appear to have reduced the amount of new fat deposited in the liver-a process called de novo lipogenesis-as well as a 26 percent reduction in fat content in the organ.

"The results of our study indicate that subjects in whom the percentage of DHA in red blood cells increased by at least 2 percent had favorable effects with changes in liver metabolism and insulin sensitivity, a factor that may contribute to reduced fat content in the liver," said Leanne Hodson, coauthor of the study.

The details of the study 

Twenty-four patients with Non-Alcoholic Hepatic Steatosis were involved during the study, 12 of whom received daily supplementation with 1.84 grams of DHA and 1.56 grams of EPA, while the rest of the participants received an olive oil placebo; both groups followed the treatment for 15 to 18 months. 

The concentration of DHA in red blood cell membranes was assessed in each participant before and after treatment, revealing that in nine patients DHA had increased by 2% or more, while in the others the increase in DHA in red blood cell membranes was less than 2%. In the group that had presented a 2% or greater increase in DHA, those who had followed supplementation were eight while only one belonged to the placebo group; suggesting that he had probably increased the amount of oilseeds in his diet during the study period. Next, the researchers evaluated the possible change in some typical parameters of NAFLD, including hepatic and whole-body insulin sensitivity, amount of hepatic fat, rate of de novo lipogenesis, and oxidation of fatty acids and triglycerides in the blood.

But what is the effect of EPA? 

In this study, the main purpose was to examine the elevating effect of increased DHA in red blood cells on markers of NAFLD. However, it was not evaluated whether EPA had any influence on these parameters, because the effects on steatosis of EPA and DHA cannot be isolated. However, a previous study concluded that DHA was more effective than EPA on changes in liver enzymes. Therefore, the researchers suggested the need for further studies to measure the effect of a supplement containing only DHA would be on liver metabolism and insulin sensitivity. 

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Source: Hodson et.al, Docosahexaenoic acid enrichment in NAFLD is associated with improvements in hepatic metabolism and hepatic insulin sensitivity: a pilot study. European Journal of Clinical Nutrition 71, 973-979 (2017).