The evidence that our diet is poorer than before is growing day by day. One of the latest to come to light is to do with the worsening functioning of the liver, which is an essential organ in the human metabolism. It acts as a powerful purifier that drains and cleans the blood, processes the nutrients in the body and plays a vital role in the digestive system.
Traditionally, liver failure has occurred through abusive consumption of alcohol, which is something that favours not only tumours but the need for a transplant, but that has changed now. These days, what destroys more livers is not what we drink but a sedentary lifestyle and the way we eat, which is increasingly unhealthy and far from the beneficial and recommended Mediterranean diet.
Fat is the main source of energy in the human body, as José María Mato of the CIC bioGUNE research centre explains. He has recently led an international study which has discovered the existence of at least three types of fatty liver disease. The finding is extremely important because this is an illness for which, at present, there is no specific treatment.
The ones that are used are therapies adapted from other illnesses such as diabetes, which have proven to be more or less effective. The findings from the research centre make it possible to determine for which type of patient the different molecules currently being tested for this disease will be most effective, and for which there would be no sense in using because they would do no good.
The calorific performance of the liver is, says Mato, eight kilocalories per gramme, which is the same as diesel.
“The evolution of the human species has selected fat as a source of energy because it really is a very energetic substance,” he says. The liver receives it from adipose tissue, processes it and then uses it to fuel the rest of the organism. With five per cent of fatty material, a liver functions like a Swiss watch, it works like clockwork. So what is the problem? It is that a sedentary lifestyle and poor diet mean that many people - in the western world - have livers with “10 per cent, 20 per cent and even 40 per cent of fat and more,” he explains.
Fat is actually necessary for life. “Birds accumulate fat in the liver before they start long migrations,” Mato says. But we humans are giving our livers too much ‘oil’ and that is making them deteriorate gradually. Little by little, and what is worse, silently, showing no symptoms. Normally, when someone finds out that something is wrong, it is because it really is a problem.
First, an excessive accumulation of fat causes what experts call hepatic steatosis. These are small accumulations of ‘sebum’ which might not cause a problem but can also cause inflammation of the tissue, and that is when the problems start. Inflammation favours the appearance of fibrosis (scars from tissue which is losing functionality) and can also be a preliminary step towards cirrhosis or a liver tumour.
It is to be hoped that nothing so dramatic occurs. “Non-alcoholic fatty liver is very common and becoming even more so, but it only causes problems in exceptional cases,” says Delia D’Avola, a specialist at the Hepatology unit at the Clínica Universidad hospital in Navarra. The problem is that the exceptional is becoming more frequent. In developed countries it affects 20 to 30 per cent of the population and as much as 70 per cent or more among people with obesity or Type 2 diabetes. It is currently the most common liver disease, more than that caused by alcohol consumption or chronic hepatitis.
The patients most at risk of getting this are, in fact, those who are obese, and they account for 90 per cent of cases, according to a recent report from the Catalonian Digestology Society. Diabetes is present in 75 per cent of those affected, and excess cholesterol and triglycerides, the most common type of fat in the human body, in 30 per cent. “Our body contains more than 200 different types of fat,” says José María Mato. “The challenge we are facing is that there are no pure non-alcoholic patients, or very few. Everyone, from a certain age, consumes some alcohol, even if only with meals and at weekends”.
However, most patients do not die of liver failure but from heart attacks, strokes and thrombosis. The alteration in the fats which cause this condition favours the formation of clots which end up triggering vascular complications. This is the reason that non-alcoholic fatty liver has become in recent years the principal subject at conferences about liver diseases. “It is a real challenge nowadays,” says Delia D’Avola.