A compound commonly found in extra-virgin olive oil can significantly reduce symptoms of insulin resistance and non-alcoholic fatty liver disease -- the adverse effects of a high-fat diet, a study has found.

Hydroxytyrosol is a polyphenol found in extra-virgin olive oil, which is known to have antioxidant properties and may play a fundamental role in its health benefits. "Our research shows that in mice fed on a high-fat diet, hydroxytyrosol exerts a protective effect in the liver," said lead author Rodrigo Valenzuela from the University of Chile.

The study conducted on a mouse showed that hydroxytyrosol was able to reduce liver enzymes that are linked to an imbalance in the fatty acid composition of the liver, brain and heart as well as increase their activity. "Our results indicate that hydroxytyrosol may be an essential part of the health benefits of extra virgin olive oil. We have demonstrated that this compound may offer protection against oxidative stress and detrimental fatty acid composition in the liver, heart and brain caused by a high-fat diet," Valenzuela noted. 

For the study, published in the journal Lipids in Health and Disease, the team fed four groups of 12-14 mice on either a high-fat diet (60 percent fat) or a control diet (10 percent fat), with or without supplementation of 5mg hydroxytyrosol per kg body weight, administered orally, for a 12 week period. The results revealed that adding a relatively small dose of hydroxytyrosol to the diet was able to reverse oxidative stress which is linked to fatty liver disease. 

Also, hydroxytyrosol also lowered the increase in levels of low-density lipoprotein or the bad cholesterol. However, these findings need to be established in humans, the researchers said.