Vegan products and a vegan diet have become popular over the last decades. Research already has shown positive effects of this diet on body weight, cholesterol levels and blood pressure. It is also shown that it improves symptoms of patients with rheumatoid arthritis. However, it´s not fully understood how this different diet composition, which -for example- contains more plant substances and less protein, contributes to these positive effects for these patients.

Hence, a study was performed, with two different groups of 24 healthy persons each, which had to follow a diet for four weeks, either rich in meat, or completely vegan, after a one-week period of ‘resetting’ first. An extensive analysis of immunological markers was performed, to our knowledge the first study of this kind. In this relatively short period of four weeks experiment, no VitB12 or folate deficiency occurred, nor was there a lack of protein, in the vegan diet group. If so, this could have led to biased results.

The research shows that a change from mixed diet to vegan diet, when compared to a meat-rich diet, results in a reduced number of specific immune-related cells.  Within these four weeks, numbers of neutrophilic granulocytes, monocytes (both part of the white blood cell family) and blood platelets were significantly lowered, compared to the meat-rich diet.

A vegan diet, which contains less so-called branched amino-acids, could thus have an effect on the numbers of these immune-related cells. Indeed, this GM-CSF decreased during the vegan diet, supporting the assumption that this diet might have a molecular based immunosuppressive effect.

(Source: Clinical Nutrition 2020. Ann-Katherin Lederer, Andrea Maul-Pavicic, Luciana Hannibal, Manuel Hettich, Carmen Steinborn, Carsten Gründemann, Amy Marisa Zimmermann-Klemd et al. https://edoc.unibas.ch/76036/)