“The present study found that dietary patterns higher in plant foods and lower in animal products were consistently associated with decelerated DNA methylation-derived aging biomarkers, specifically GrimAge2 and PhenoAge.”
As people live longer, maintaining good health is becoming just as important as extending lifespan. While chronological age simply reflects the number of years a person has lived, biological age measures how well the body is functioning and may better predict future health. Researchers have increasingly focused on lifestyle factors that may slow biological aging, and diet has emerged as one of the most promising.
A research paper published in Volume 18 of Aging titled “Plant-based dietary patterns are associated with slower epigenetic aging,” investigated whether diets emphasizing plant foods are associated with slower biological aging as measured by DNA methylation-based epigenetic clocks.
Looking Beyond Chronological Age
Not everyone ages at the same rate. While two individuals may share the same chronological age, one may remain healthier and more resilient than the other because their biological age is lower.
One of the most widely used approaches involves measuring DNA methylation, a natural chemical modification of DNA that changes throughout life. These patterns can be analyzed using so-called epigenetic clocks, including GrimAge2, PhenoAge, and HannumAge, which have been shown to predict future risks of chronic disease, disability, and mortality more accurately than chronological age alone.
Previous studies have suggested that healthy dietary patterns may help slow epigenetic aging. However, it remained unclear whether plant-based diets in people who do not necessarily follow vegetarian or vegan lifestyles are associated with these biological aging markers.
Comparing Different Types of Plant-Based Diets
To investigate this question, the researchers analyzed data from two large U.S. population studies: the Atherosclerosis Risk in Communities (ARIC) Study and the National Health and Nutrition Examination Survey (NHANES). Together, the analysis included more than 4,800 middle-aged and older adults.
Rather than simply comparing vegetarians with non-vegetarians, the investigators evaluated four different plant-based dietary patterns:
- Overall Plant-Based Diet Index (PDI), which rewards greater intake of plant foods and lower intake of animal foods.
- Provegetarian Diet Index, which emphasizes relatively higher consumption of plant foods while reducing animal products.
- Healthy Plant-Based Diet Index (healthy PDI), which favors nutrient-rich foods such as fruits, vegetables, whole grains, legumes, and nuts.
- Unhealthy Plant-Based Diet Index (unhealthy PDI), which reflects greater intake of refined grains, sugary foods, and other less nutritious plant-derived foods.
The researchers then examined whether these dietary patterns were associated with three widely used measures of epigenetic aging after accounting for age, lifestyle, socioeconomic factors, smoking, alcohol use, physical activity, and other potential confounding variables.
Healthier Plant-Based Diets Were Linked to Slower Epigenetic Aging
The study found that greater adherence to overall plant-based diets, provegetarian diets, and healthy plant-based diets was consistently associated with slower biological aging.
Participants with higher scores for the overall plant-based diet and provegetarian diet showed slower GrimAge2 and PhenoAge acceleration. Higher adherence to the overall plant-based diet was also associated with slower HannumAge. Healthy plant-based diets were linked to slower GrimAge2, although the associations with the other epigenetic clocks were less consistent.
In contrast, unhealthy plant-based diets showed no significant association with any of the biological aging measures.
These findings suggest that the quality of plant foods matters. Simply consuming fewer animal products may not be enough if the diet relies heavily on refined carbohydrates, added sugars, and other less nutritious plant-based foods.
How Diet Influences Biological Aging
Although this study was not designed to identify the underlying biological mechanisms, the authors discuss several possibilities.
Plant-based diets are typically rich in dietary fiber, vitamins, minerals, antioxidants, and other bioactive compounds that are thought to help reduce oxidative stress and chronic inflammation, two processes believed to contribute to biological aging. These diets have also been associated with improved blood pressure, healthier cholesterol levels, better glucose regulation, and reduced risk of cardiovascular disease.
Over time, these favorable metabolic effects may influence DNA methylation patterns, resulting in slower progression of biological aging as measured by epigenetic clocks.
The researchers also note that plant-based diets are not all alike. Diets centered on whole, minimally processed plant foods appear to offer greater health benefits than those dominated by refined grains, sugary beverages, and highly processed plant-derived products.
What Makes This Study Different?
Unlike many previous studies that focused on vegetarian or vegan diets, this investigation evaluated plant-based eating patterns in a largely non-vegetarian population.
This distinction is important because many people adopt diets that increase plant food consumption without completely eliminating animal products. The findings suggest that even moderate shifts toward healthier plant-based eating patterns may be associated with measurable differences in biological aging.
Another strength of the study is its use of two large, independent U.S. cohorts and multiple validated epigenetic aging measures, increasing confidence that the observed associations were consistent across different populations.
Looking Ahead
The authors conclude that dietary patterns emphasizing healthy plant foods and limiting animal products are associated with slower epigenetic aging. While the study cannot establish cause and effect, it adds to growing evidence that long-term dietary habits may influence biological processes linked to aging and future health.
Additional research, including long-term intervention studies, will be needed to determine whether adopting healthier plant-based diets can directly slow biological aging over time. As scientists continue exploring the relationship between nutrition and longevity, this study suggests that everyday food choices may play an important role in promoting healthier aging at the molecular level.
Click here to read the full research paper published in Aging.
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