Gene pathways associated with mitochondrial function, oxidative stress and telomere length are differentially expressed in the liver of rats fed lifelong on virgin olive, sunflower or fish oils
This study investigates the effect of lifelong intake of different fat sources rich in monounsaturated (virgin olive oil), n6 polyunsaturated (sunflower oil) or n3 polyunsaturated (fish oil) fatty acids in the aged liver. Male Wistar rats fed lifelong on diets differing in the fat source were killed at 6 and at 24 months of age. Liver histopathology, mitochondrialultrastructure, biogenesis, oxidative stress, mitochondrial electron transport chain, relative telomere length and gene expression profiles were studied. Aging led to lipid accumulationin the liver. Virgin olive oil led to the lowest oxidation and ultrastructural alterations. Sunflower oil induced fibrosis, ultrastructural alterations and high oxidation. Fish oil intensified oxidation associated with age, lowered electron transport chain activity and enhanced the relative telomere length. Gene expression changes associated with age in animals fed virgin olive oil and fish oil were related mostly to mitochondrial function and oxidative stress pathways, followed by cell cycle and telomere length control. Sunflower oil avoided gene expression changes related to age. According to the results, virgin olive oil might be considered the dietary fat source that best preserves the liver during the aging process.
Long-term consumption of sunflower and fish oils damages the liver
An international group of scientists led by the University of Granada (UGR) has demonstrated that the long-term intake of sunflower or fish oils damages the liver and can cause a series of alterations in it, giving rise to non-alcoholic steatohepatitis (NASH).
NASH, which causes inflammation of the liver that is not caused by alcohol abuse, is a very serious condition and can act as a catalyst for 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, recently published in the prestigious Journal of Nutritional Biochemistry, analysed how the long-term consumption of different dietary fat sources such as olive, sunflower and fish oil affects the liver of rats. UGR researchers conducted a series of comprehensive analyses, including studies of pathological anatomy, ultrastructural analyses using electron microscopes, sophisticated bioenergy techniques, telomere length measurements, and oxidative stress. Most importantly, they conducted a comprehensive study of the liver genome in order to establish how it evolved in line with the consumption of the different oils.