On 3rd August 2026, a study published in the journal MedComm found that switching to a vegan diet for just one month can alter the body’s epigenetic landscape in ways linked to reduced inflammation and slower biological ageing. The research, carried out by scientists at the University of California San Diego and the University of Freiburg in Germany, looked at DNA methylation, the chemical process that determines whether genes are switched on or off without changing the underlying DNA sequence itself.
In the randomised clinical trial, 48 healthy adults followed the same standardised diet for a week before being assigned at random to either a vegan diet or a meat-rich diet for four weeks. Both diets provided similar calorie intake, allowing the researchers to isolate the effects of diet composition rather than weight loss. More than 800,000 methylation sites across the genome were analysed before and after the intervention.
Those on the vegan diet showed changes consistent with a less inflammatory immune state, including lower predicted proportions of neutrophils and higher proportions of regulatory CD4 T cells. The group also showed increased promoter methylation in genes linked to cancer-related and cell growth pathways (since more methylation usually means less gene activity, this suggests those genes that make cancer cells grow were being suppressed), along with shifts suggesting reduced lipid metabolism activity and increased activity in insulin signalling and DNA repair. Two epigenetic clocks designed to predict health outcomes indicated a deceleration in biological ageing among the vegan group.
Jerome Mertens, PhD, associate professor of neurosciences at UC San Diego School of Medicine and co-senior author of the study, said, “Our genes are not our destiny. The remarkable finding isn’t simply that one diet outperformed another. It’s that the epigenome responded measurably in just four weeks, showing that our biology is far more dynamic — and responsive to everyday choices — than we often assume.”
Lukas Karbacher, UC San Diego School of Medicine neuroscience graduate student and first author of the study, said, “That agreement told us we weren’t just seeing changes on a computer screen, we were detecting real and meaningful biological changes.”
Max Storz, MD, from the University of Freiburg Medical Center and co-senior author of the study, said, “Our study adds to growing evidence that nutrition can shape biology at the molecular level. The next step is to understand whether these epigenetic changes persist over time and whether they translate into meaningful improvements in long-term health. That will require larger clinical studies, but these findings provide an important foundation.”
