Nutrition: “Cheat days” temporarily impair the immune system
16.08.2023 10:43
Researchers at the University Hospital Hamburg-Eppendorf (UKE) have found in a study that repeated short-term deviations from a regular and balanced diet towards a high-fat diet with little fiber can have significant consequences for the human immune system. The scientists have published their research results in the journal Nature Immunology.
The international research team led by Prof. Dr. Nicola Gagliani, research group leader in the clinic and polyclinic for general, visceral and thoracic surgery at the UKE, carried out various laboratory experiments for the study and then a subject study. The participants received a high-fiber diet for five days; They then ate a high-fat, low-fiber diet for another five days.
“Window of immune deficiency opens for a certain period of time”
The scientists were able to determine that the lower fiber content in a diet rich in fat and energy leads to a reduction in microbial metabolic products, so-called short-chain fatty acids. This reduces the function of CD4+T cells, an important cell type in the adaptive immune system. True, these effects are temporary, as resuming a balanced diet with sufficient fiber restores the body's immunity. At the same time, the scientists were able to show that switching to a diet that is high in fat and low in fiber is associated with a higher susceptibility to infections: “The window of immune deficiency opens for a certain period of time. In our study, we were able to show how synchronized our nutritional behavior and our immune reactions are and how even a short-term switch to overeating leads to a rapid impairment of the immune system,” explains Prof. Gagliani. “Our data highlights how quickly and profoundly our daily food choices can impact our health. To put it positively, this means that the effectiveness of vaccines and immunotherapies could be maximized with the help of a regular, balanced diet,” adds lead author Dr. Francesco Siracusa, Clinic and Polyclinic for General, Visceral and Thoracic Surgery at the UKE.