The immune system reacts similarly to a high fat and high calorie diet as to a bacterial infection. This is shown by a recent study led by the University of Bonn. Particularly disturbing: Unhealthy food seems to make the body’s defenses more aggressive in the long term. Even long after switching to a healthy diet, inflammation towards innate immune stimulation is more pronounced. These long-term changes may be involved in the development of arteriosclerosis and diabetes, diseases linked to Western diet consumption. The results will be published in the journal Cell.
The scientists placed mice for a month on a so-called “Western diet”: high in fat, high in sugar, and low in fiber. The animals consequently developed a strong inflammatory response throughout the body, almost like after infection with dangerous bacteria. “The unhealthy diet led to an unexpected increase in the number of certain immune cells in the blood of the mice, especially granulocytes and monocytes. This was an indication for an involvement of immune cell progenitors in the bone marrow,” Anette Christ, postdoctoral fellow in the Institute of Innate Immunity of the University of Bonn explains. To better understand these unexpected findings, bone marrow progenitors for major immune cell types were isolated from mice fed a Western diet or healthy control diet and a systematic analysis of their function and activation state was performed.