Fast food affects the immune system extremely negatively, in such a way that it becomes more aggressive and the corresponding person more susceptible to chronic diseases.
Fast food panics the immune system
An unhealthy diet can have dramatic consequences, as we have known for a long time, but we are happy to ignore them. Even life expectancy, which has been continuously increasing over the past centuries, will most likely experience a decline again. Because people who are born today have a shorter lifespan ahead of them than their parents. The main causes are an unhealthy diet and lack of exercise.
In 2018, researchers from the University of Bonn showed how an unhealthy diet with a high proportion of fast food damages the immune system and thus overall health. Their study results appeared in the journal Cell. In it, they wrote that unhealthy food puts the immune system in an aggressive mood in the long term and that the resulting chronic inflammatory processes persist for a long time even after switching to a healthy diet.
Fast food like pathogens The immune system reacts to fast food as it does to pathogens
For their study, the scientists from the Institute for Innate Immunity (iii Bonn) gave mice a typical Western diet (high in fat, high in sugar, and low in fiber) for four weeks. The immune system of the animals then behaved throughout the body as if dangerous bacteria had invaded.
There was an unexpected increase in certain defense cells (granulocytes and monocytes) in the blood, which is an indication of the activity of so-called progenitor cells in the bone marrow – according to Dr. Anette Christ from iii Bonn. Progenitor cells are precursor cells from which u. a. the defense cells mentioned can develop. The higher the activity of progenitor cells in the bone marrow, the more active the immune system is.
The immune system remains on alert
“Gene analyzes then showed that the Western diet activated a large number of genes in the progenitor cells that are responsible for these cells growing, maturing, and multiplying,” explains Prof. Dr. Joachim Schultze from the Life & Medical Sciences Institute (LIMES) at the University of Bonn and the German Center for Neurodegenerative Diseases (DZNE). So fast food seems to lead to the rapid recruitment of a large and strong army of defense cells in the body.
If the mice received a species-appropriate diet consisting of e.g. cereals, although the acute inflammation in the body disappeared, the genetic programming of the defense cells remained, which means that these cells remained active and were still in the mode of reproduction.
“It was only recently discovered that the innate immune system has a kind of memory,” says Prof. Dr. Eicke Latz, head of iii Bonn and scientist at the DZNE. “Once an infection has been overcome, the body’s own defense system remains on the alert so that it can act quickly if another bacterial attack should occur.” In the mice examined, however, it was not a bacterial infection that led to this immune system reaction, but rather a simple one fast food.
Fast food changes the genetic makeup
The Bonn researchers then also discovered which part of the immune system is responsible for this memory. These are so-called inflammasomes (NLRP3), protein complexes in the immune cells that recognize bacteria or other harmful things and then immediately release highly inflammatory messenger substances. However, how exactly the NLRP3 inflammasomes recognize fast food still needs to be investigated.
In addition to the acute inflammatory reaction described and the ongoing alertness of the immune system, the scientists working with Latz and Schultze were able to observe another special feature.
Fast-food-induced immune system activation also changed the way genetic material is packaged in the cell nucleus. Genetic material comes in the form of two strands of DNA that together are more than two meters long. Normally, these strands of DNA are wrapped around certain proteins, which means that some genes cannot be “read” (remain inactive) simply because they are inaccessible.
You can think of DNA as a ball of yarn. Those genes that lie in the middle of the ball of yarn remain unreachable. Fast food, however, ensures that the DNA suddenly loosens, and in some places, small loops hang out of the ball of wool. The genes, which were previously well hidden and packaged but are now on these loops, can suddenly be read very easily.
Fast food leads to illness
The consequence of this altered gene situation is that the immune system becomes hyperactive and reacts to minor triggers with strong inflammatory processes. These, in turn, accelerate the development of chronic diseases such as B. vascular diseases (arteriosclerosis) and diabetes type 2.
In arteriosclerosis, for example, the deposits in the blood vessels consist mainly of fats (lipids) and defense cells. Inflammatory processes now contribute directly to the growth of these deposits, since the constantly newly activated defense cells continuously migrate into the damaged blood vessel walls. If the deposits become too thick, parts can detach from them, which can then lead to a blockage of the vessels (thrombosis) with the consequences of a stroke or heart attack.
See through the temptations of the food industry
“Our results have enormous social significance”
says Professor Latz. The basics of a healthy diet should therefore take up a significantly larger part of education in the future than has been the case up to now. It would be ideal if children learned to see through the temptations of the food industry at an early age and were then able to independently decide on a healthy alternative.
In practice, it has been shown that this works particularly well if, firstly, the parents and other family members set a good example and, secondly, the child is explained exactly why this or that is not healthy.