An international scientists group led by the University of Granada (UGR) has demonstrated that liver can be damaged and suffers a series of alterations after a long-term intake of sunflower or fish oils, giving rise to non-alcoholic steatohepatitis (NASH). NASH, which causes a fatty liver inflammation not related to the alcohol abuse, is a very serious hepatic disease because can be the onset of other diseases such as cirrhosis and liver cancer. Its prevalence in the general population increases with age: it affects 1% to 3% of children, 5% of teenagers, 18% of those aged between 20 and 40, 39% of those aged between 40 and 50, and more than 40% of those over 70.

The research, published in the Journal of Nutritional Biochemistry, analyses how the long-term consumption over the life of different dietary fat sources such as olive, sunflower and fish oil, affects the liver health of the rats. UGR researchers made to the animals a series of comprehensive analyses, including studies of pathological anatomy, ultrastructural analyses using electron microscope, very sophisticated bioenergy techniques, telomere length measurements, oxidative stress and most notably a thorough liver genome research to check how it developed in accordance with the different oils intake.

Some of those involved researchers in this study. José Luis Quiles on the left and Alfonso Varela on the right side.

As José Luis Quiles Morales, laid author of this research, Physiology professor at UGR declares: “the study demonstrates that fat is accumulated in the liver with age but the most striking aspect is that the type of the fat is different in line with the consumption and that means, notwithstanding this accumulation, some livers are healthier than others and more or less likely to suffer certain diseases with age”.

Of this way, from the three dietary fats studied (virgin olive oil, sunflower oil and fish oils), virgin olive oil was the best to preserving the liver throughout life while sunflower oil induced fibrosis, ultrastructural alterations, genetic expression blockage and high oxidation. For its part, fish oil intensified oxidation associated with ageing, reduced mitochondrial electron transport chain activity and altered the relative telomere length (chromosomes ends whose shortening can cause cells ageing and lengthening to the cancer).