Study: Multiple dietary patterns linked to slower biological aging

A study by DZNE finds that healthy eating is associated with slower biological aging-and that there is more than one way to eat healthily. The researchers examined ten dietary patterns considered healthy, including the Mediterranean, Nordic, and a plant-based diet, as well as the DASH diet, which is designed to help lower blood pressure. All were linked with slower biological aging, with age-related changes in the DNA serving as markers. These results, based on data from DZNE's Rhineland Study and confirmed with data from an independent study, are published in the journal Nature Communications. 

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. Importantly, there is probably no single 'correct' diet. According to our data, various dietary patterns are associated with slower aging, some more, some less. That is an encouraging finding, because it leaves room to tailor healthy eating to personal and cultural preferences, budget and taste." 

Prof. Monique Breteler, Director of Population Health Sciences at DZNE and head of the Rhineland Study

Molecular aging measures 

For their analysis, the researchers evaluated blood samples and dietary habits from about 7,500 women and men: This included 6,470 participants of DZNE's Rhineland Study in Bonn-where the findings were initially made-and 1,034 participants of the EPIC-Potsdam Study of the German Institute of Human Nutrition Potsdam-Rehbrücke (DIfE), where the key results were independently confirmed. 

From blood, the team determined chemical modifications in the DNA, known as "DNA methylation patterns", which influence gene activity and thus biological mechanisms. Since these molecular markers change systematically over the course of life, they are considered indicators of biological aging. 

"We applied three different approaches, so-called epigenetic clocks, to read biological aging from DNA methylation," explains Juliana Tavares, a doctoral researcher at DZNE and lead author of the current publication. "To this end, we leveraged state-of-the-art technology, which allowed us to cover about 850,000 sites in the DNA. This is roughly twice as many as in most previous studies." 

Healthy eating: Different for everyone 

The researchers also matched every participant's eating habits against the recommendations of each of the ten diets studied. Adherence was quantified and graded using a scoring system based on how closely individuals followed each dietary pattern. "One and the same person could therefore rank high on one diet score and low on another. In other words: People who ate healthily by one standard were often not the same people who ate healthily by another. According to our data, hardly anyone counts as a healthy eater by every standard at once," says Tavares. 

However, across the board, higher diet quality was associated with slower biological aging. This applied to all of the ten diets examined. "While there are measurably differences between the diets, they are modest in absolute terms. It's the big picture what matters," says Tavares. "In summary: When it comes to slowing down the aging process, there isn't just one healthy diet, but indeed a whole repertoire of possible diets with a positive effect."

One result was particularly noteworthy: the association between diet quality and slower biological aging was most pronounced in smokers, even though smokers were by no means eating healthier than non-smokers. The biological explanation is still open. "Smoking is very harmful to health," says Tavares, "One explanation for our findings might be that there is just more health benefit to gain for smokers by eating healthy because of the enormous detrimental effects of smoking." 

Shared biological pathways 

Although each dietary pattern was associated with its own distinct set of DNA methylation sites, the biological mechanisms involved showed substantial overlap. "More than 70 percent of the affected biological pathways were shared across all diets. These involve cell structure, cell signaling and metabolism-processes central to aging and chronic disease. Therefore, it is understandable that the dietary patterns we examined were all linked with a slowing of biological aging," says Tavares. "A few pathways were diet-specific, and they matched each diet's main objectives: heart-related pathways were unique to the DASH diet, and pathways related to cognition and memory were unique to the so-called MIND diet, which aims to support brain health. You don't need a perfect diet - that may be the most practical message here. But moving forward, the diet-specific pathways point to future research on targeted dietary interventions. This could be helpful in designing targeted health recommendations."