Following a Mediterranean diet might be a recipe for a long life because it appears to keep people genetically younger, say US researchers.
Its mix of vegetables, olive oil, fresh fish and fruits may stop our DNA code from scrambling as we age, according to a study in the British Medical Journal.
Nurses who adhered to the diet had fewer signs of ageing in their cells.
The researchers from Boston followed the health of nearly 5,000 nurses over more than a decade.
The Mediterranean diet has been repeatedly linked to health gains, such as cutting the risk of heart disease.
Although it's not clear exactly what makes it so good, its key components - an abundance of fresh fruit and vegetables as well as poultry and fish, rather than lots of red meat, butter and animal fats - all have well documented beneficial effects on the body.
Foods rich in vitamins appear to provide a buffer against stress and damage of tissues and cells. And it appears from this latest study that a Mediterranean diet helps protect our DNA.
The researchers looked at tiny structures called telomeres that safeguard the ends of our chromosomes, which store our DNA code.
These protective caps prevent the loss of genetic information during cell division.
In the study, nurses who largely stuck to eating a Mediterranean diet had longer, healthier telomeres.
No individual dietary component shone out as best, which the researchers say highlights the importance of having a well-rounded diet.