A large study involving 6,470 adults aged 30 to 95 years has found that following certain healthy diets may be linked to slower biological aging. Researchers from the German Centre for Neurodegenerative Diseases (DZNE) examined how participants' eating habits relate to eight different diets considered beneficial for health. These include the Mediterranean diet, DASH diet, Nordic diet, MIND diet, anti-inflammatory diet, EAT-Lancet diet, Alternate Healthy Eating diet, Plant Based Diet, and Healthful Plant-based Diet. These diets commonly emphasize plant-based foods, fiber, healthy fats, and limit red meat, ultra-processed foods, fried foods, refined carbohydrates, and sugary drinks. To measure biological aging, the researchers used DNA methylation profiles, a method that estimates age through "epigenetic clocks." These clocks assess chemical changes in DNA that occur as people age. The study analyzed around 850,000 DNA sites, more than twice as many as in earlier studies. Published in Nature Communications, the findings suggest that following a "healthy" diet is associated with slower biological aging. While the effects are described as modest, they are measurable and could be important for preventing diseases. The study found that different diets were linked to slower aging, but the differences between them were small in absolute terms. Juliana Tavares, a PhD student at DZNE and lead author, noted that the overall approach to diet is more important than specific variations between the diets. The research also found that more than 70% of the biological pathways affected by these diets were common across all of them. These pathways are involved in cellular structure, signaling, and metabolism, which are key to aging and chronic diseases. An unexpected result was that the link between diet quality and slower aging was strongest among smokers compared to non-smokers. This suggests that smokers might benefit especially from adopting a healthier diet. The study also confirmed that the DASH diet was associated with metabolic pathways related to heart and vascular health, while the MIND diet was linked to brain health pathways.