It’s no secret that eating more plants is good for you (and the planet). Yet while many people are opting to reduce their meat intake, few are committing to a fully vegan diet.
Well, all that may be about change in the wake of a new study suggesting that adopting a vegan diet for just eight weeks may help turn back the clock on your biological age. The researchers found that participants following a vegan diet showed reductions in biological age estimations, as measured by a biomarker known as DNA methylation.
“DNA methylation and other epigenetic modifications work like a volume knob for our genes, turning their activity up or down,” Dr Lucia Aronica, co-author of the study, told BBC Science Focus.
“As we grow older, the pattern of these methyl groups on our DNA changes in specific ways, which scientists can track to understand ageing better. By studying these patterns, researchers can determine someone's biological age, which might be different from their actual age based on years.”
The study, published in BMC Medicine, involved 21 pairs of adult identical twins. One twin from each pair was assigned to follow a vegan diet, while the other maintained an omnivorous diet that included meat, eggs and dairy.
The study lasted for eight weeks, with participants consuming prepared meals for the first half and self-prepared meals for the second half after receiving nutritional education.
The team then investigated the impact of each diet by taking blood samples from each participant and measuring their levels of DNA methylation.
The results showed decreases in epigenetic ageing clocks only in the vegan group – by some measures going vegan knocked almost an entire year off their age. Additionally, the vegan diet was associated with reductions in the estimated ages of various organ systems, including the heart, hormone, liver, and inflammatory and metabolic systems.
Once these were all accounted for, the average reduction in biological age for the vegan group was an impressive 0.63 years.
“Most strikingly, the pace of ageing, which calculates how quickly one's biological age advances relative to their chronological age, decreased by about 0.03 units,” the study’s lead author Dr Varun Dwaraka told BBC Science Focus. “This suggests that for every year these individuals age, their bodies age slightly less than they would typically expect.”
However, the researchers urged caution in interpreting these results. The participants who ate the vegan diet also lost two kilograms more than the omnivorous group on average. It's not clear whether the vegan diet itself or the extra weight loss it caused is the main reason for these age-related changes.
“It's impossible to pinpoint exactly which aspects of the vegan diet contributed to the observed changes in DNA methylation from this study,” Dwaraka said.
Dwaraka explained that as epigenetic clocks measure broad changes across many genes, it’s difficult to link the results to any specific dietary components.
“The study was designed to compare overall diet types – vegan versus omnivore – without isolating specific nutrients or food groups within those diets,” he added.
While the findings are promising, the authors emphasised the need for further research to understand the long-term effects of vegan diets on ageing and to disentangle the impacts of dietary composition from weight loss.
Other experts agree. “The sample size is a little too low to really extrapolate much from the results to the general population in my opinion,” Dr Lifang Hou, a professor of preventive medicine at Northwestern University who was not involved with the study, told BBC Science Focus.
“I’d be interested in seeing a follow-up study looking at biological ageing in people who stick with a vegan diet for years, and a study where the vegan diet is removed to see how many of the biological changes revert to the baseline level,” she said.
About our experts
Lucia Aronica's research focuses on epigenetics – how environmental factors can influence gene activity and health outcomes. Currently, she leads epigenetic analysis for the DIETFITS study by Dr Christopher Gardner, the largest trial ever on low-carb versus low-fat diets for weight loss. Aronica also teaches Nutritional Genomics at Stanford Continuing Studies, Stanford Sports Medicine, and the Stanford Center for Professional Development.
Varun Dwaraka is the Head of Bioinformatics at TruDiagnostic, and an ageing and longevity investigator specializing in epigenetics and bioinformatics. He has co-authored numerous publications relating to genetics, epigenetic clocks, DNA methylation and tissue regeneration.
Lifang Hou, MD, MS, PhD is a professor of preventive medicine. With a multidisciplinary background in medicine, basic science, and epidemiology, Dr Hou’s research interest lies in integrating traditional epidemiologic methods with the ever-advancing molecular techniques in multi-disciplinary research focusing on identifying key molecular markers and understanding their potential impact on disease aetiology, detection, and prevention.
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