New Study Reveals Connection Between Non-Alcoholic Fatty Liver Disease and Olive Oil Consumption

A new study was published on Nature on April 15th which studied the connection between olive oil and fatty liver disease. Specifically, the performance of olive oil consumption was studied in the context of a high fat diet (HFD) and non-alcoholic fatty liver disease (NAFLD). Olive oil consumption seemed to improve some parameters and leave others unaffected.

Context: Different Types of Fatty Acids Have Different Effects

The excessive consumption of fatty acids (i.e., fat) has been connected to non-alcoholic fatty liver disease (NAFLD). Fatty liver disease is associated with insulin resistance (IR), which could affect 1 out of 3 adults in the USA.

There are many different kinds of fatty acids, depending on their composition. The variation among fatty acids is so great that some are considered beneficial while others detrimental to human health. Fatty acid composition is a crucial factor for the development and management of fatty liver disease.

Olive oil is the main source of monounsaturated fatty acids for Mediterranean populations. In this context, it is very interesting to see how the consumption of olive oil affected various health factors in the contexts of high fat diets, obesity and fatty liver disease. Is olive oil good for fatty liver disease?

Experiment Design: Approaching the Human Fatty Liver Condition

The trial was done on obese mice, specifically female
Ldlr−/−.Leiden mice which are a great model with affinity to the human fatty liver condition. Numerous factors were tested throughout the 32-week-long trial including body weight, lipid profile, transaminases, glucose homeostasis, transcriptome and liver pathology.

Diet Profile: Which Different Diets Were Tested?

Besides the low fat diet (LFD) that was used as a control diet, three types of high-fat diets (HFDs) were tested.


Group 1: Lard-Based High Fat Diet (HFD)

A typical lard was the main ingredient of this high-fat diet, since most previous experiments on obese mice used this ingredient.


Group 2: EVOO-Based HFD

Extra virgin olive oil (EVOO) was the main ingredient of this high-fat diet. EVOO has a diverse fatty acid profile. Its effects shed new light on the importance of fatty acid composition.


Group 3: Polyphenol-Rich-EVOO-Based HFD

Certain olive oils have an increased content of natural antioxidants, called polyphenols. Polyphenol-rich olive oil was the main fat of this HFD.

What Were the Results of the Study?

  • Both Group 2 and Group 3 demonstrated significant improvements when compared to Group 1. Specifically, both olive oil-consuming groups were capable to reduce body weight (BW) and improve insulin sensitivity. 
  • At the same time, both olive oil-consuming groups did not improve transaminase value, increased both LDL and HDL cholesterol, and also increased liver collagen content. 
  • Liver inflammation and fibrosis were not improved despite the weight loss and insulin sensitivity improvement. The consumption of both types of olive oil initiated a hepatic gene expression cascade that eventually supported these conditions, similar to the lard-based diet.
  • An interesting observation is that while both olive oil groups increased LDL cholesterol on the same level, polyphenol rich olive oil provided a boost to HDL cholesterol, also known as the “good” cholesterol.

Conclusion: Editor’s Note

High quality extra virgin olive oil is one of the healthiest fats and can provide health benefits even in existing, impaired conditions such as non-alcoholic fatty liver disease. However, its potential is limited if the consumption is greater than what the organism can handle. There is no miracle food. Since olive oil is a fat of high caloric value, it is mportant to consume it consciously and in moderation. 

Athanasios Demeslis

Athanasios Demeslis

Olive Farmer / Olive Oil Producer / Editor on

This article was prepared by Athanasios for Myrolion’s readers after studying the official scientific paper. For more details or to contact the conductors of the study, please follow the first link of the article.