Ten Healthy Diets Tied to Slower Biological Aging in 6,470 Adults

Eating in line with a range of well-known healthy diets is associated with slower biological aging, according to a study in Nature Communications reported by ScienceAlert. Researchers found the link for all 10 sets of dietary guidelines they examined, not just one favored plan.

The effect was modest, the authors say, and the study shows an association rather than proof that food changes how fast the body ages. Still, the team says the results suggest there is no single "right" diet to follow.

The study in five numbers

• 10 diet guidelines: The team compared participants' eating habits against 10 established scoring systems, including the Mediterranean, Nordic, DASH and MIND diets.
• 6,470 participants: The main analysis used data from people aged 30 and over, led by a team at the German Centre for Neurodegenerative Diseases (DZNE).
• 850,000 DNA sites: The researchers read chemical tags at about this many sites, which epidemiologist Juliana Tavares said is roughly twice as many as in most earlier studies.
• More than 70 percent: This share of the affected biological pathways was common to all the diets, according to Tavares. They involve cell structure, cell signaling and metabolism.
• 1,034 people: A separate group of this size was analyzed the same way to check the findings.

How biological aging was measured

Biological aging describes how quickly the body is wearing out, which does not always match the number of birthdays a person has had. ScienceAlert noted that faster aging tends to go with a shorter lifespan and more health problems later in life.

To estimate it, the researchers looked at DNA methylation, a pattern of chemical tags on DNA that shifts with biological age. They applied three different "epigenetic clocks" to read that pattern from blood samples.

Each person's diet was scored against the 10 guidelines. Eight of them reward healthy eating, including the Alternate Healthy Eating Index, the Plant-based Diet Index, the Healthful Plant-based Diet Index and the EAT-Lancet Diet. The other two, the Unhealthful Plant-based Diet Index and the Dietary Inflammatory Index, effectively measure unhealthy eating, such as sugary drinks and sweets. For those two, lower scores went with slower aging.

What the researchers found

Across all 10, healthier eating was linked to slower biological aging. Some diets showed distinct patterns. ScienceAlert reported that the DASH diet was tied to aspects of heart health, and the MIND diet to cognition and memory. Even so, the overlap between diets was large.

Monique Breteler, an epidemiologist at DZNE, said the effects are not massive but are measurable and relevant for prevention. She said slowing aging could reduce the risk of age-related diseases such as dementia or cardiovascular disorders.

Why it matters for everyday eating

The main practical point is flexibility. Breteler said the findings leave room to adapt healthy eating to personal and cultural preferences, budget and taste. ScienceAlert noted that hardly any participants scored highly on every set of guidelines, and it appears that following just one of them was enough to be associated with a lower chance of biological age running ahead of chronological age.

Tavares put it this way: "You don't need a perfect diet." She described that as perhaps the most practical message of the work.

What the study cannot show

The research does not demonstrate cause and effect. The data are a snapshot in time, so they cannot show how changing what you eat over the years alters DNA methylation. People who eat well may also differ from others in ways that affect aging, and the study as described by ScienceAlert cannot separate those factors from diet itself. The same associations appeared in the separate group of 1,034 people, broadly speaking, which lends support to the pattern but does not settle the question of cause.

What researchers want to study next

The authors suggest that future studies could follow how diet changes over an extended period affect DNA methylation. Tavares said the diet-specific pathways point toward research on targeted dietary interventions, which could help in designing more tailored health recommendations.

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Around Prague, based on reporting by ScienceAlert