Adhering to healthier dietary guidelines could help slow the biological ageing of the body, a new study published in the scientific journal Nature Communications has shown. Scientists analysed 10 different dietary patterns and found that greater adherence to healthier guidelines was associated with slower ageing.
The research was conducted by a team led by scientists from the German Center for Neurodegenerative Diseases (DZNE). It included data from 6,470 people aged over 30, whose dietary habits were compared with blood biomarkers that allow for the assessment of biological age. Biological age indicates how fast the body ages and does not necessarily correspond to the number of years a person has lived; accelerated biological ageing is linked to shorter life expectancy and a higher risk of health problems in later life.
"The effects are not extremely large, but they are measurable and important for prevention," highlighted epidemiologist Monique Breteler from the DZNE. She added that slowing the ageing process could contribute to reducing the risk of diseases associated with older age, including dementia and cardiovascular diseases.
Among the patterns analysed were the Mediterranean diet, known for its emphasis on vegetables, fruit, whole grains and olive oil, and the Nordic diet. The DASH diet, designed to lower blood pressure, and the MIND diet, which combines the principles of the Mediterranean and DASH diets with a specific focus on maintaining brain health, were also analysed. The study included the alternative healthy eating index (AHEI-2010), the plant-based diet index (PDI), the healthy plant-based diet index (hPDI), the EAT-Lancet diet, the unhealthy plant-based diet index (uPDI) and the dietary inflammatory index (DII). The last two indices do not represent healthy diet models but measure dietary patterns associated with less favourable health effects, for example the consumption of sweetened beverages and confectionery. In their case, lower scores, meaning less adherence to such patterns, were associated with slower biological ageing.
To assess the biological age of the participants, researchers studied DNA methylation patterns, chemical changes that affect gene activity and change during ageing. They applied three different so-called epigenetic clocks, or methods for estimating biological age based on DNA methylation, using technology that enabled the analysis of approximately 850,000 sites on DNA, roughly twice as many as in most previous studies.
Epidemiologist Juliana Tavares from the DZNE explained that different dietary patterns had certain specific effects. The DASH diet was associated with changes relating to heart health, while the MIND diet showed an association with processes important for cognitive abilities and memory. A large part of the biological processes affected by diet was common to all analysed patterns. "More than 70 per cent of the affected biological pathways were common to all dietary patterns," said Tavares. These processes include cell structure, cell signalling and metabolism, which play a significant role in ageing and the development of chronic diseases.
The results were further verified in a separate group of 1,034 people, yielding largely similar results. In that group as well, a healthier diet was associated with slower biological ageing. Scientists highlight that almost none of the participants achieved high scores across all analysed dietary guidelines, suggesting that it may not be necessary to follow all models simultaneously to achieve potential benefits. "You do not have to have a perfect diet. That is perhaps the most important practical message of this research," Tavares concluded.
