The immune system reacts in the same way to a bad diet as to a bacterial infection: it becomes aggressive and goes out of control. In the long term, this change can promote the development of atherosclerosis and diabetes, suggests a study published in the journal Cell.
We know that the diet of Westerners, rich in fats and sugars and low in fiber, has harmful consequences on weight. In recent years, the consumption of such foods has increased, contributing to the obesity epidemic in Europe. We know most of the complications related to obesity. However, according to a recent study, a poor diet can also have negative consequences on the immune system.
Junk food: the immune system feels attacked
Scientists at the University of Bonn put mice on a “Western” diet for a month. These mice developed a significant inflammatory response throughout the body. Their poor diet caused an increase in the number of immune cells, mainly granulocytes and monocytes, in their blood.
Genomic studies had already shown that a Western diet caused, in stem cells, the activation of many genes responsible for the proliferation and aging of cells. A poor diet therefore causes the activation of many defense cells, which leads to an inflammatory reaction.
A junk food sensor in immune cells
The acute inflammation immediately disappeared when the mice resumed their usual diet, but the stem cells remained active for a long time. After four weeks on the “normal” diet, many of the genes activated when the mice were fed the Western diet were still active.
This comes from the fact that the immune system remains in a sort of state of alert after an infection, so that the body can react more quickly in the event of a new attack. The same thing happens with a bacterial infection. In the long term, the immune system has become increasingly aggressive.
Scientists have discovered a ‘fast-food sensor’ in immune cells. In several mice, an “NLRP3 inflammasome” was found, a protein complex that recognizes infectious and harmful agents and therefore sends a defense signal, causing an immune reaction.
This new study reveals that the immune system reacts aggressively to a poor diet, even long after the resumption of a healthy diet. The basics of a healthy diet should occupy a much more important place in education, from an early age. It’s a way of protecting children early on from unhealthy eating and preparing them to make consciously healthy choices.
Christ A et al. Western Diet Triggers NLRP3-Dependent Innate Immune Reprogramming. Cell, 2018.