One Month on a Vegan Diet Shifts Epigenetic Patterns Associated with Aging and Inflammation
story<br>School of Medicine<br>Health Sciences
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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.
Study adds to growing evidence that nutrition can shape biology at the molecular level. Photo by iStock/zi3000
Story by:
Lizelda Lopez
llopez2@ucsd.edu
Published Date
August 04, 2026
Story by:
Lizelda Lopez
llopez2@ucsd.edu
Topics covered:
Epigenetics
DNA methylation
Vegan diet
Nutrition
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Key Takeaways
A one-month randomized trial found a vegan diet altered DNA methylation patterns linked to inflammation, cell growth and metabolism.<br>Participants on the vegan diet showed immune-regulatory changes consistent with a less inflammatory state.<br>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 in MedComm, 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."
— Jerome Mertens, PhD, associate professor of neurosciences at UC San Diego School of Medicine and co-senior author of the study
“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....