One Month on a Vegan Diet Shifts Epigenetic Patterns Associated with Aging and Inflammation
Genome-wide analysis found a vegan diet reshaped the DNA methylation landscape associated with immune cell composition and health-related measures of biological aging
Story by:
- Lizelda Lopez
–
llopez2@ucsd.edu
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Published Date
August 04, 2026
Story by:
- Lizelda Lopez
–
llopez2@ucsd.edu
Topics covered:
Article Content
- A one-month randomized trial found a vegan diet altered DNA methylation patterns linked to inflammation, cell growth and metabolism.
- Participants on the vegan diet showed immune-regulatory changes consistent with a less inflammatory state.
- Two clocks designed to predict health outcomes suggested participants following the vegan diet experienced a deceleration in biological aging over the one-month study period.
Researchers from University of California San Diego and University of Freiburg in Germany have found that switching to a vegan diet for just one month can alter the body’s epigenetic landscape in ways associated with reduced inflammation and biological aging. In a randomized clinical trial, participants assigned to a vegan diet vs. a meat-rich diet showed changes in DNA methylation — a biological process that regulates whether genes are more or less active — that were linked to immune function, metabolism and cancer-related pathways. The findings, published on August 3, 2026 inMedComm, suggest dietary choices can rapidly influence molecular processes associated with long-term health.
“Our genes are not our destiny,” said Jerome Mertens, PhD, associate professor of neurosciences at UC San Diego School of Medicine and co-senior author of the study. “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.”
Diet has long been linked to the risk of chronic diseases such as cardiovascular disease, diabetes and certain cancers. Yet scientists have only begun to understand how food influences the epigenome — the layer of chemical modifications that helps determine which genes are turned on or off without changing the underlying DNA sequence
To explore these effects, researchers analyzed genome-wide DNA methylation patterns in blood samples from 48 healthy adults who participated in a randomized dietary intervention. After following the same standardized diet for one week, participants were randomly assigned to either a vegan diet or a meat-rich diet for one month. Both diets were designed to provide similar calorie intake, allowing researchers to isolate the effects of diet composition rather than weight loss
The team examined more than 800,000 methylation sites across the genome before and after the intervention. Rather than looking for changes in individual genes alone, the researchers focused on broader biological patterns that changed in response to diet
The researchers also found evidence that the vegan diet shifted the immune system toward a less inflammatory state. 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. Those predictions closely matched blood cell measurements collected during the original clinical trial
“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.”
“That agreement told us we weren’t just seeing changes on a computer screen — we were detecting real and meaningful biological changes,” said Lukas Karbacher, UC San Diego School of Medicine neuroscience graduate student and first author of the study
The findings build on earlier evidence that plant-based diets can influence immune function while providing additional insight into the molecular changes that accompany those effects
In addition to immune signals, the researchers found that the vegan diet was associated with increased promoter methylation in genes involved in several cancer-related and cell growth pathways. Increased promoter methylation can reduce the activity of genes within these pathways, suggesting the diet may influence cellular processes involved in growth and proliferation. The researchers also observed changes consistent with reduced activity in lipid metabolism pathways and increased activity in pathways related to insulin signaling, DNA repair and cellular stress responses.
Perhaps the most striking finding concerned biological aging itself. For this, the researchers examined biological age using epigenetic clocks — a mathematical biomarker that estimates a person’s biological age based on DNA methylation patterns rather than years lived. Two clocks designed to predict health outcomes suggested participants following the vegan diet experienced a deceleration in biological aging over the one-month study period. A third clock, optimized to predict chronological age rather than health outcomes, showed a different pattern, highlighting that epigenetic clocks measure different aspects of aging.
“These findings reinforce the idea that not all measures of biological aging capture the same biology,” said Mertens. “The clocks associated with disease risk and overall health consistently pointed in the same direction, suggesting the dietary changes were influencing pathways tied to health rather than simply the passage of time.”
The researchers caution that the study was relatively small, involving 48 healthy adults, and lasted only one month. Because the observed DNA methylation changes were modest and spread across hundreds of thousands of sites in the genome, larger and longer studies will be needed to confirm the findings and determine whether the molecular changes translate into measurable reductions in disease risk
While the findings do not demonstrate that a vegan diet prevents cancer or reverses aging, they provide new insight into how dietary choices may rapidly influence the biological processes that underlie inflammation and age-related disease
“Our study adds to growing evidence that nutrition can shape biology at the molecular level,” said Max Storz, MD, from University of Freiburg Medical Center and co-senior author of the study. “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.” Storz also stressed that the findings are not the result of reduced calories, but rather a matter of diet composition.
Read the full study: [A vegan diet epigenetically modulates inflammatory pathways and biological aging: Genome-wide DNA methylation analysis of a one-month isocaloric vegan versus meat-rich dietary intervention]
Additional co-authors on the study include: Stefanie Kowarschik, Manching Ku and Roman Huber at University of Freiburg Hospital; and Ann-Kathrin Lederer, University Medical Center of the Johannes Gutenberg University Mainz
The Ministry of Science, Research and Arts of the state Baden-Württemberg, Germany, financed the position of Lederer within the Academic Center for Complementary and Integrative Medicine (AZKIM), otherwise the study was financed by institutional re
The authors declare no conflicts of interest
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