What we eat has long been linked to our risk of developing conditions such as heart disease, diabetes and cancer.
But scientists are increasingly interested in a deeper question: can food influence the way our genes behave?
A new study published in the journal MedComm suggests the answer may be yes.
Researchers from the University of California San Diego and the University of Freiburg in Germany set out to examine how different diets affect the epigenome, a collection of chemical modifications that help regulate which genes are switched on or off without altering DNA itself.
The team recruited 48 healthy adults and, after an initial week on the same standardized diet, randomly assigned them to follow either a vegan diet or a meat-rich diet for one month.
Both eating plans were designed to provide a similar number of calories, allowing the researchers to focus on the effects of diet composition rather than weight loss alone.
Blood samples were collected before and after the intervention, enabling researchers to analyze more than 800,000 DNA methylation sites across the genome.
DNA methylation is a process that can influence gene activity and is often used by scientists to study aging and disease risk.
Rather than concentrating on individual genes, the researchers looked for broader biological patterns.
They found that participants assigned to the vegan diet showed changes in DNA methylation linked to immune function, metabolism and pathways associated with cell growth.
The analysis also suggested a shift toward a less inflammatory immune profile, including lower levels of neutrophils, a type of immune cell involved in inflammation, and higher proportions of CD4 T cells, which help regulate immune responses.
The most striking finding emerged when the team examined several so-called “epigenetic clocks,” tools that estimate biological age based on DNA methylation patterns.
According to two health-related epigenetic clocks known as PhenoAge and GrimAge, people following the vegan diet experienced a deceleration in biological aging over the month-long study period.
In other words, molecular markers associated with aging moved in a direction generally linked to better long-term health outcomes.
Researchers also observed evidence that the vegan diet influenced pathways related to lipid metabolism, insulin signaling and cancer-associated biological processes.
Jerome Mertens, Ph.D., associate professor of neurosciences at UC San Diego School of Medicine and co-senior author of the study, said the speed of the changes came as a surprise.
“We were actually surprised at how quickly the epigenome responded, as we typically think of epigenetic changes to be rather slow, or ‘sluggish,’ but lasting,” Mertens told Newsweek. “My expectation is that some of these changes would persist and possibly deepen over time, but we need larger, longer studies to prove that.”
The authors cautioned that the research was relatively small and lasted only one month.
While the findings suggest dietary changes can quickly influence molecular processes associated with aging and inflammation, larger and longer-term studies will be needed to determine whether those epigenetic shifts translate into measurable health benefits over time.
Asked what advice he would give people who are not ready to adopt a fully vegan diet, Mertens said even modest changes could potentially move people in a similar direction.
“One could probably see similar directional changes by making plants the default and meat the exception,” he said. “Replacing red and processed meats regularly with alternatives is probably a practical way to nudge inflammation associated epigenetic patterns toward what we saw in the vegan group.”
However, he stressed that there is no one-size-fits-all approach.
“Everyone’s biology, preferences, and starting point are different and each one of us should find diet changes that are realistic and enjoyable,” he said.
Reference
L. Karbacher, J. Mertens, S. Kowarschik, et al. “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.” MedComm 7, no. 8 (2026): e70899. https://doi.org/10.1002/mco2.70899
Contact Newsweek editors on this story: Kara Dolman and Emma Lee-Sang
