People know they should eat healthy foods if they want to maintain their bodies into old age, but a lot of the time we're likely to focus on the health of the major organs that occupy our torso.

However, a new study looking at the diets of elderly people says we can enjoy greater longevity if we eat foods that are good for our brain, and suggests that those who follow a Mediterranean-like diet – consisting of more fish and vegetables, along with less meat and dairy – may lose fewer brains cells due to ageing.

"These results are exciting, as they raise the possibility that people may potentially prevent brain shrinking and the effects of ageing on the brain simply by following a healthy diet," said Yian Gu of Columbia University in the US.

Gu and her colleagues examined the diets of 674 people who were older than 80 years of age and did not have dementia. The participants completed questionnaires about the food they ate and had their brains scanned afterwards.

The researchers divided the participants into two separate groups depending on the content of their diet. One group contained people who followed Mediterranean diet principles in at least five food components – including greater amounts of healthy foods or less consumption of unhealthy foods. The other group contained those who did not eat a Mediterranean-like diet.

When the researchers compared the two sets of brain scans, they found that the people who followed a Mediterranean-style diet had a total brain volume that was 13.11 millilitres larger than those in the other group. Their grey matter volume was 5 ml larger, and white matter volume was 6.41 ml larger.

It might not sound like much, but in terms of brain longevity, Gu says the difference is significant. "The magnitude of the association with brain measures was relatively small, but when you consider that eating at least five of the recommended Mediterranean diet components has an association comparable to five years of ageing, that is substantial," she said.

It's important to note that the researchers aren't claiming that the Mediterranean diet is responsible for the greater brain volume – just that there's an association going on here that they still need to get the bottom of. In any case, it's definitely food for thought. (Sorry.)

The findings are published in Neurology.