A randomized trial has shown that a vegan diet can significantly alter DNA methylation patterns linked to inflammation and biological aging within just one month. Conducted by researchers from the University of California San Diego and the University of Freiburg, the study found participants on a vegan diet exhibited changes in immune cell composition, indicating a shift towards a less inflammatory state.
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The study, published on August 3, 2026, in MedComm, involved healthy adults who were assigned to either a vegan diet or a meat-rich diet after a week of following a standardized regimen. The diets were designed to ensure similar calorie intake, allowing researchers to focus on the effects of diet composition itself, rather than weight loss.
Using genome-wide analysis, researchers examined over 800,000 methylation sites in blood samples before and after the dietary intervention. They discovered that the vegan diet correlated with decreased activity of genes associated with inflammation and possibly reduced cancer risk. Specifically, DNA methylation analyses indicated lower percentages of neutrophils, the immune cells that drive inflammation, and higher levels of CD4 T cells, which help regulate immune responses.
Jerome Mertens, PhD, associate professor at UC San Diego, emphasized that the results signify a dynamic interplay between diet and biology, stating that our genetics do not solely determine our health outcomes. Lukas Karbacher, a graduate student involved in the study, noted that the observed biological changes were not just theoretical; they aligned with actual alterations in blood cell measurements.
The vegan diet was also associated with increased promoter methylation in genes linked to cancer and cell growth pathways, potentially indicating effects on cellular growth processes. Changes were noted in lipid metabolism and signaling pathways related to insulin and DNA repair.
Notably, the study indicated that participants on a vegan diet experienced a deceleration in biological aging, as assessed by two different epigenetic clocks, which predict health outcomes based on DNA methylation patterns.
Although the study involved a limited sample of 48 individuals and lasted only four weeks, the findings contribute to the understanding of how dietary choices can influence biological processes linked to inflammation and aging. The researchers call for larger, longer-term studies to establish whether these epigenetic changes can lead to significant reductions in disease risk in the long run.
Max Storz, MD, from the University of Freiburg, highlighted that these findings underscore the importance of diet composition itself rather than calorie reduction. The study was funded by institutional resources, and the authors declared no conflicts of interest.