- A recent study suggests that eating a vegan diet, even for a short time, may help reduce inflammation and slow biological aging.
- The diet aids in these areas by altering DNA methylation patterns, which are chemical markers that regulate gene expression.
- Although promising, the study findings are preliminary, and larger, longer-term studies are necessary to determine whether these changes could lead to meaningful health benefits.
Vegan dietary plans have gained popularity in recent years, with an increasing number of people opting to reduce or eliminate animal products from their diets. Concerns about animal welfare, the environmental impact of food production, and the potential health benefits likely influence this growing adoption.
As vegan options have become more widely available, following a vegan eating plan has also become more accessible and convenient. As a result, veganism has developed into a more mainstream dietary choice.
Now, a small randomized clinical trial suggests that eating a vegan diet for as little as 4 weeks may help reduce inflammation and even slow biological aging.
The findings, published in
However, the study involved only 48 healthy adults, and lasted for a month. As such, larger, longer-term studies are needed to determine whether the changes persist and translate into better health outcomes.
What did the study find?
Researchers from the University of California, San Diego, and the University of Freiburg analyzed blood samples from 48 healthy adults who first followed a standardized diet for a week. Participants were then randomly assigned to follow either a vegan diet or a meat-rich diet for a month.
The diets were designed to provide similar amounts of calories, allowing the researchers to investigate whether differences in food composition, rather than simply calorie intake or weight change, could account for the observed changes.
DNA methylation involves chemical modifications that do not alter underlying DNA, but can influence whether particular genes are more or less active. The researchers examined more than 800,000 DNA methylation sites across the genome before and after the dietary intervention.
They found several changes in the vegan group involving pathways related to immune function, metabolism, cell growth, insulin signaling, DNA repair, and cellular responses to stress.
As such, it suggests that adopting a vegan dietary plan may influence mechanisms that regulate gene activity.
“I find these findings interesting, but it is important we are careful with how we state the headline,” said Michelle Routhenstein, MS, RD, CDCES, CDN, a registered dietitian nutritionist who specializes in heart disease at Entirely Nourished, and who was not involved in this study.
“This study was a small, short term study in 48 healthy adults, and the researchers were looking at changes in DNA methylation, which is basically a chemical tagging system that helps control how genes are turned on and off. These changes can be influenced by diet, inflammation, activity, and aging. They are biological markers, not proof that is actually aging more slowly or will live longer.”
—Michelle Routhenstein, MS, RD
Similar previous research supports findings
“In 2023, we published the results of an 8-week study conducted in 22 pairs of identical twins. Our results were very similar to the recent study,” explained Christopher Gardner, PhD, the Rehnborg Farquhar Professor of Medicine at Stanford University, and Director of Nutrition Studies at the Stanford Prevention Research Center, who was also not involved in the study.
“We looked at chronological vs. biological aging with epigenetic clocks (similar to the recent study) and telomere length. In just 8 weeks, the twins randomized to these diets had aging measures that improved relative to their matched identical twins that were assigned a healthy omnivorous diet,” he continued.
Omnivores vs. vegans
“In our study, compared to the omnivorous study participants, the vegan participants experienced lower LDL-cholesterol, lower fasting insulin, lower weight, less aging (according to markers above), and had improved gut microbiome impacts.”
—Christopher Gardner, PhD
“We are not surprised by these recent findings, and are pleased to see that the types of findings we got in our study are being replicated in other studies. The replication makes the strength of the findings better solidified,” Gardner added.
Could a vegan diet cause a shift toward a less inflammatory state?
The DNA methylation patterns in those following a vegan dietary plan were associated with lower proportions of neutrophils and higher proportions of CD4 T cells.
Neutrophils are white blood cells that play an important role in defending the body against infection. However, excessive or prolonged inflammatory activity can contribute to tissue damage and chronic disease. CD4+ T cells help coordinate and regulate immune responses against disease and infection.
The methylation-based estimates also correspond with blood-cell measurements obtained during the
However, this does not mean that a vegan eating plan necessarily prevents inflammation or inflammatory disease.
Instead, the findings suggest that changing dietary patterns may influence biological pathways involved in the body’s immune response.
Did the vegan diet actually make people biologically younger?
Unlike chronological age, which measures how many years a person has lived, biological age measures how the body is functioning. Researchers can estimate it using
Two of the aging measures used in the study, PhenoAge and GrimAge, suggest that biological aging slowed in the vegan group during the 4-week intervention.
However, a third measure, Blood&Skin, produced a different result, showing age acceleration instead. This is important as different epigenetic clocks measure different aspects of aging and do not necessarily provide identical results.
Therefore, the findings should not be interpreted as a vegan eating plan reversing aging. Instead, they provide preliminary evidence that a short-term dietary intervention can affect molecular markers that researchers associate with biological aging.
What does this mean for people considering a vegan eating plan?
The findings support the role of nutrigenomics, which is the study of how diet and genes interact to affect a person’s health and risk of developing diseases.
A well-planned vegan diet can provide substantial amounts of vegetables, fruits, whole grains, legumes, nuts, and seeds.
However, simply removing animal products does not automatically make a dietary plan healthy. A vegan diet can also include highly processed foods that are high in added sugars, sodium, or saturated fats, and may require a person to pay attention to nutrients that can be more difficult to obtain from plant foods, including vitamin B12.
“It is important to recognize that when someone replaces a meat-heavy diet, they may also be eating less saturated fat and processed meat, which has been associated with aging,” Routhenstein told Medical News Today.
“I would not interpret these findings as meaning that animal foods are inherently inflammatory. It is more likely that the overall shift toward more plant foods and less processed and meat-heavy foods is influencing several pathways involved in inflammation and metabolism.”
Diet quality matters
“(T)he quality of the diet matters within a vegan diet. A diet can technically be vegan while being high in refined carbohydrates, sugary foods, fried foods, and highly processed vegan products,” Routhenstein said.
“(Y)ou do not have to go fully vegan to support healthy aging and longevity. Increasing the amount and variety of plant foods in your diet can provide many of these benefits while still allowing you to include animal foods,” she added.
“A good quality vegan diet is typically composed of foods and food groups that are recommended, and avoids or minimizes foods that are of low/lower nutritional quality,” Gardner told MNT.
“The recent study looked at inflammation and aging. However, there are decades of studies that suggest a good quality vegan diet is associated with lower risk of heart disease, cancer, diabetes, obesity and stroke, and their risk factors,” he said.
Study limitations
While encouraging, the study has several important limitations.
It was a small study that only included 48 healthy adults. As such, it may not be representative for how different people may respond to a vegan eating plan. Additionally, the intervention only lasted 4 weeks, so it is unclear whether the DNA methylation changes would remain after returning to usual diets, or whether maintaining a vegan diet for longer would produce larger or different effects.
Furthermore, the researchers only measure methylation changes in blood. Epigenetic patterns can differ between tissues, so changes in blood do not mean that identical changes may occur in organs such as the liver, brain, muscle, or adipose tissue.
The study also only measured molecular markers rather than long-term clinical outcomes. This means that it does not demonstrate that a vegan eating plan can prevent cancer, cardiovascular disease, dementia, or other age-related conditions, nor does it establish that the diet extends lifespan.
While further research is necessary, the findings suggest that the relationship between diet and health may extend beyond calories, body weight, and conventional blood markers, potentially reaching into the mechanisms that help regulate how cells function.
