Humans do not always age biologically at the same rate as their chronological age. Faster biological ageing compared to chronological age has been linked to higher risks of disease and mortality. According to a recent study, a diet low in vegetables and fruits and high in red meat, fast food, and sugar-sweetened soft drinks was associated with accelerated biological ageing even in young adulthood.

The rate of biological ageing indicates the discrepancy between chronological age and biological age, that is, whether a person is biologically older or younger than their chronological age. Biological ageing can be measured using epigenetic clocks. Epigenetic clocks are computational models developed through machine learning methods that predict biological age based on methyl groups that regulate the expression of genes.

A study conducted at the University of Jyväskylä and the Gerontology Research Center investigated whether diet predicts the rate of biological ageing in young adulthood. The study participants were twins between the ages of 20 and 25.

According to the results, diets characterised by low intake of vegetables and fruits and high consumption of red and processed meat, fast food, and sugar-sweetened soft drinks were associated with faster biological ageing. Conversely, diets rich in vegetables and fruits and low in meat, fast food, and sugary soft drinks were associated with slower biological ageing.

'Some of the observed associations may also be explained by other lifestyle factors, such as physical activity, smoking, and body weight, as healthy and unhealthy lifestyle habits tend to cluster in the same individuals,' says postdoctoral researcher Suvi Ravi. 'However, diet maintained a small independent association with ageing even when we accounted for other lifestyle factors.'

Since the study participants were twins, the research was able to investigate the genetic influence on the relationship between diet and biological age. The results suggest that a shared genetic background, but not the shared childhood environment of the twins, explains the relationship between diet and ageing in young adulthood. 'However, this does not mean that a health-promoting diet would not benefit everyone,' emphasises Ravi.

The study is a part of the research project 'The role of nutrition in the prevention of common diseases'. This sub-study utilised data from the FinnTwin12 study. A total of 826 individual twins and 363 twin pairs participated in the study. Diet was assessed using a food frequency questionnaire, where participants reported the typical consumption frequency of 55 food items.

The principal investigator of this study, Suvi Ravi, is a member of the GenActive research group. The GenActive group investigates genetic and lifestyle factors that predict biological ageing, health, and functional capacity. The group is led by Elina Sillanpää, Associate Professor of Health Promotion.