PARIS, Mar. 4. (Benin News) –
A high-fat diet is not enough to cause short-term fatty liver disease. However, if this diet is combined with the consumption of drinks sweetened with liquid fructose, the accumulation of fat in the liver accelerates and hypertriglyceridemia appears, a cardiovascular risk factor, according to research from the Faculty of Pharmacy and Science. Food, the Institute of Biomedicine of the University of Barcelona (IBUB) and CIBEROBN.
The study, carried out on an experimental rat model, shows that the effect of fructose on the increase in the synthesis of fatty acids in the liver is more decisive than the external supply of fats through food.
“In high-fat diets supplemented with liquid fructose, this monosaccharide is able to induce an increase in de novo lipogenesis – that is, the formation of fat from sugars – and an inhibition of oxidation of lipids in the liver”, explains Professor Juan Carlos Laguna, from the Department of Pharmacology, Toxicology and Therapeutic Chemistry.
Published in the journal “Molecular Nutrition and Food Research”, it benefited from the collaboration of researchers Aleix Sala-Vila and Iolanda Lázaro (Medical Research Institute of Hospital del Mar, IMIM) and José Rodríguez-Morató (IMIM, University Pompeu Fabra-CEXS), among other experts.
Fructose or fruit sugar is one of the most common sweeteners in the food industry. This simple sugar (monosaccharide) is obtained industrially from corn syrup, a product derived from corn. With high sweetness and low cost of production, fructose is used by the food industry to sweeten drinks, sauces and processed foods, despite scientific evidence linking it to metabolic diseases that are risk factors for cardiovascular disease.
“Specifically, fructose consumption directly affects the expression and activity of nuclear factor ChREBP. Once activated, this factor is responsible for the increased expression of enzymes that control hepatic fatty acid synthesis. In parallel, fructose consumption also reduces the activity of the nuclear receptor PPARalpha, which is mainly responsible for controlling the expression of genes coding for enzymes involved in fatty acid oxidation (mitochondrial and peroxisomal) in the liver. , he says.
As the new preclinical study indicates, it is the combination of dietary saturated fat and the induction of endogenous fatty acid synthesis that causes the rapid onset of fatty liver disease. “In addition, we describe for the first time that fructose – unlike the high-fat diet – increases the PNPLA3 protein, which is associated with the development of hypertriglyceridemia, a risk factor for cardiovascular disease”, explains Núria Roglans, co -author of the study and member of the same department at UB.
HEPATIC STEATOSIS IN MEN
Several epidemiological studies associate the consumption of fructose-sweetened beverages with non-alcoholic fatty liver disease (NAFLD), a condition for which no specific drug treatment is yet available. In these patients, de novo lipogenesis contributes up to 30% of the lipids accumulated in the liver, whereas in healthy people, this process of synthesis contributes only 5% of the hepatic lipids.
The animal model that characterized the team will be of potential interest for the study of future drugs to treat non-alcoholic fatty liver disease (NAFLD). “People with NAFLD have higher endogenous lipid synthesis activity in the liver than healthy people. It is therefore quite likely that the effects described in this study also occur in humans,” say the experts.
“Unfortunately, fatty liver disease is the starting point for more serious pathologies, such as steatohepatitis and cirrhosis. It is a practically asymptomatic pathology, although in some cases mild and non-specific digestive disorders may appear. Apart from a healthy diet and physical exercise, there is currently no effective pharmacological treatment for this pathology”, he specifies.
It should be noted that the effects described in the study are only observable if fructose – the sugar in fruits – is ingested in liquid form. “In the case of sugary drinks, fructose is rapidly absorbed and reaches the liver en masse, producing the metabolic alterations described. To make a comparison, we might speak of the appearance of a fructose overdose when fructose is ingested in the form of sugary drinks,” the team points out.
