Mediterranean diet protects against DNA ageing

Women who consume a Mediterranean-style diet are less likely to show evidence of 'cellular ageing' and therefore more likely to live longer, say US researchers.

Consuming a diet rich in fresh fruit and vegetables, olive oil, whole grains and fish rather than red meat has been repeatedly linked to better health.

The new study, published in the BMJ shows that adherence to such a diet is also associated with something thought to indicate good general health - longer telomeres.

Telomeres are stretches of DNA that cap the chromosomes, protecting the transfer of genetic information during cell division. The length of these structures diminishes with age, but stress and environmental factors have also been shown to affect them.

In their study, the researchers tracked the health of 4,676 healthy women for over a decade, and all subjects filled in questionnaires about their eating habits.

Dr Marta Crous-Bou, the lead author of the study, from Harvard University in the USA, said: 'Our findings showed that healthy eating, overall, was associated with longer telomeres. However, the strongest association was observed among women who adhered to the Mediterranean diet.'

The specific dietary components of Mediterranean diet that might be driving this association were not identified, however.

Dr David Llewellyn, a senior research fellow in clinical epidemiology at the University of Exeter, who was not involved in the study, told the BBC: 'All observational studies have the potential to produce misleading estimates, and we should not assume that the association with telomere length is necessarily causal.'

However, he called the research a 'large, well-conducted study' and said that 'exploring the relationship between diet and biological markers of ageing provides new clues about the processes that may contribute to the development of key age-related conditions'.

Previous studies have suggested that obesity, smoking and high consumption of sugary drinks can all shorten telomeres, and people with shorter telomeres seem to have an increased risk of coronary heart disease.

Dr Mike Knapton, associate medical director at the British Heart Foundation, said: 'Longer telomeres may partially explain the link between diet and risk of cardiovascular disease.'

He added: 'These results reinforce our advice [on] eating a balanced and healthy diet.'