Unhealthy eating makes our immune system aggressive

Fat and high calorie diet makes the immune system more aggressive

The diet in the modern industrial nations is often too rich in fat and calories. Accordingly, the spread of health problems such as obesity and diabetes is increasing. What effect the unhealthy diet has on the immune system in the long term has remained largely unclear. According to a recent study, the diet rich in fat and calories triggers an immune system reaction that is similar to a bacterial infection and causes increased inflammatory reactions in the long term.

The international research team under the leadership of scientists at the University of Bonn has shown that the unhealthy food not only leads to an activation of the immune system in the short term, but also makes body defense more aggressive in the long term. For a long time after switching to a healthy diet, it will therefore be faster inflammation. This will directly promote the development of arteriosclerosis and diabetes. The study results were published in the journal "Cell".

Unhealthy diet high in fat and calories changes the immune system in the long term. (Image: Alexander Raths / fotolia.com)

Unexpected increase in immune cells

As part of the study, the researchers gave mice a so-called "western diet" for a month with plenty of fat, high sugar and low fiber. As a result, the animals "developed a massive body-wide inflammation, almost as if they were infected by dangerous bacteria," according to the release of the Rheinische Friedrich-Wilhelms-Universität Bonn.

According to Anette Christ, postdoctoral researcher at the Institute for Innate Immunity of the University of Bonn, "the unhealthy diet has led to an unexpected increase in some immune cells in the blood." This is an indication of an involvement of progenitor cells in the bone marrow in the inflammatory process.

Large number of genes activated

In further investigations, researchers isolated and analyzed the progenitor cells of immune cells from the bone marrow of the mice in order to better understand the changes. The genomic studies have actually shown that a large number of genes were activated in the precursor cells by the Western diet, reports Prof. Dr. med. Joachim Schultze from the Life & Medical Sciences Institute (LIMES) of the University of Bonn and the German Center for Neurodegenerative Diseases (DZNE).

Long-term genetic reprogramming

Among the activated genes were, among other hereditary factors for their reproduction and maturation and the "fast food causes the body quickly recruited a huge powerful combat force," said Prof. Schultze. If the mice were then offered the type-specific cereal diet for four weeks, the acute inflammation disappeared, but the genetic reprogramming of the immune cells persisted.

"Even after these four weeks many of the hereditary factors were active in them, which had been switched on in the fast-food phase," said researchers at the University of Bonn.

Immune system has a memory

Only recently, according to Professor Eicke Latz, director of the Institute for Innate Immunity of the University of Bonn and scientist at the DZNE, known, "that the innate immune system has a memory." After infection, the body's defense in a kind of alarm state, then react faster to a new attack can. However, this process, called "innate immune training," was not triggered by a bacterium in the mice, but by an unhealthy diet.

Identified "fast food sensor"

In their study, the scientists were even able to identify the "fast-food sensor" in the immune cells responsible for the effect, according to the Bonn University Communication. A study of the blood cells in 120 test persons was able to demonstrate that in some subjects, the innate immune system shows a particularly strong training effect. Genetic studies have shown that it involves a so-called inflammasome.

Inflammasome activated by certain food ingredients

As sensors of the innate immune system, inflammas detect harmful substances and subsequently release highly inflammatory messengers, explain the scientists. The identified inflammasome is activated by certain food ingredients, which in addition to the acute inflammatory reaction also has long-term consequences. Thus, according to the researchers, the way in which the genetic information is packaged is changed.

Epigenetic changes through the diet

The DNA threads with the genetic information are wrapped around proteins and strongly entangled, which is why many genes on the DNA can not be read - they are simply too poorly accessible, the scientists explain. The unhealthy diet causes some of these normally hidden DNA parts to unroll, making the areas of the genetic material easier to read in the long term. These so-called epigenetic changes are triggered by the inflammasome, explains Professor Latz. The immune system reacts in the sequence to small stimuli with stronger inflammatory responses.

Increased risk of diabetes, arteriosclerosis, strokes and heart attacks

The altered inflammatory response drastically accelerates the development of vascular disease or type 2 diabetes, according to the scientists. For example, in arteriosclerosis, the growth of typical vascular deposits (so-called plaques) is promoted by the inflammatory reaction. If the plaques become too large, they burst open, are carried away by the bloodstream and can clog other vessels, which in the worst case can result in a stroke or heart attack, the researchers explain.

The altered inflammatory response also increases the risk of a heart attack. (Image: hriana / fotolia.com)

Dramatic consequences of unhealthy diet

Thus, according to the researchers, malnutrition shows dramatic long-term consequences. According to Prof. Latz, this finding has enormous social relevance. In recent centuries, average life expectancy in Western countries has been rising steadily, but this trend is breaking for the first time. Who is born today will probably live on average probably shorter than his parents, with improper diet and too little exercise according to the experts have a decisive role.

According to Professor Latz, the basics of a healthy diet need to become much more prevalent than they are today, as children can only be immunized early enough against the temptations of the food industry before long-term consequences develop. Today, children have choices about what they eat every day and "we should enable them to make informed choices in their diet," the expert said. (Fp)