A large study involving approximately 7,500 people suggests that eating a healthy diet may help slow biological aging, and there is no single eating plan that stands above all others.
Scientists at the German Center for Neurodegenerative Diseases (DZNE) investigated 10 different dietary patterns, including the Mediterranean, Nordic, plant-based, and DASH diets. The DASH diet was specifically developed to help reduce blood pressure.
Every dietary pattern examined was associated with slower biological aging, as measured by chemical changes in DNA that reflect the body's aging process.
The findings were first identified using data from DZNE's Rhineland Study and then independently confirmed in another population.
"Our study suggests that healthy eating goes hand in hand with slower biological aging. The effects are not massive, but they are measurable and relevant for prevention. By slowing the aging process, the risk of age-related diseases such as dementia or cardiovascular disorders can be reduced. Thus, healthy eating contributes to healthy aging," said the head of the Rhineland Study. "Importantly, there is probably no single 'correct' diet….various dietary patterns are associated with slower aging, some more, some less.”
Measuring biological aging through DNA
To investigate the connection between diet and aging, the scientists analyzed dietary information and blood samples from roughly 7,500 men and women.
The initial analysis included 6,470 participants in DZNE's Rhineland Study in Bonn, Germany. The researchers then tested their findings using data from another 1,034 people enrolled in the EPIC-Potsdam Study.
Rather than relying only on participants' chronological ages, the team looked for molecular signs of aging in their blood.
Specifically, they measured DNA methylation, a process involving chemical modifications to DNA that help regulate gene activity and influence how cells function.
The researchers estimated biological age involves using epigenetic clocks, tools that analyze small chemical tags on DNA called methylation markers. These markers change in predictable ways with age and may influence how cells function, repair themselves and respond to stress.
10 healthy diets linked to slower aging
The next step was to determine how closely each participant followed the 10 dietary patterns. Researchers compared reported food consumption with the recommendations for each diet and assigned scores reflecting how well individuals followed those guidelines.
Because the diets emphasize different foods and nutritional goals, a person could receive a high score for one eating pattern while scoring poorly on another. In fact, participants who met one definition of healthy eating often did not meet the requirements of other diets.
Despite those differences, the overall pattern was remarkably consistent. Better adherence to every one of the 10 diets was associated with slower biological aging. Some eating patterns showed stronger associations than others, but the absolute differences were relatively small.
A surprising finding among smokers
One unexpected result emerged when researchers examined the association between diet and aging among smokers. The link between healthier eating and slower biological aging was stronger in smokers than in nonsmokers, even though smokers did not generally have healthier diets.
The researchers have not yet determined what biological processes might explain this difference.
One possibility is that the extensive damage caused by smoking leaves greater room for measurable improvements associated with healthier eating. However, the finding does not lessen the well-established dangers of tobacco use.
Different diets share common aging pathways
The scientists also investigated which biological processes might connect the different diets to slower aging.
Although each eating pattern was associated with changes at a distinct collection of DNA methylation sites, the underlying biological pathways were surprisingly similar.
More than 70% of the affected pathways were shared across all 10 diets. These processes help regulate essential functions such as cellular structure, communication between cells, and metabolism. They also play important roles in aging and the development of chronic diseases.
The researchers identified some differences that reflected the specific goals of individual diets. For example, the DASH diet was associated with pathways related to heart health, while the MIND diet, which was developed to support brain health, showed distinct associations with pathways involved in memory and cognitive function.
In other words, while the Mediterranean, DASH, Nordic and other healthy diets may not work in exactly the same way, they seem to influence the same underlying processes associated with healthy aging.
interventions. This could be helpful in designing targeted health recommendations."
Source: Nature Communications, August 29, 2026.
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