Switching to a vegan diet — even for a month — can physically alter the body's inflammation and aging markers, according to a report released from UC San Diego researchers. A UCSD team was joined by researchers from University of Freiburg in Germany to run a randomized clinical trial. Participants were assigned either a vegan diet or a meat-rich diet. The vegan diet also changed the immune system to a less inflammatory state. According to the researchers, the DNA methylation analyses predicted lower proportions of neutrophils — immune cells that drive inflammation — and higher proportions of CD4 T cells, which help regulate immune responses.