Image copyright Thinkstock Image caption A Mediterranean diet is rich in fruit, vegetables and healthy fats like olive oil

A Mediterranean diet can help older adults maintain bigger brains, new research has suggested

A study of pensioners in Scotland found that those with a diet rich in fresh fruit, vegetables and olive oil had healthier brains than those with different eating habits.

They suffered less brain shrinkage than those who regularly ate meat and dairy products.

The study was carried out by University of Edinburgh researchers.

They carried out brain scans on 401 people in their 70s who did not have dementia and who provided information about what they ate.

Learning and memory

The Mediterranean diet is rich in vegetables, fruits, olive oil, beans and cereal grains and includes moderate amounts of fish, dairy products and wine while limiting consumption of red meat and poultry.

Scientists found that those who adhered most closely to the diet retained significantly greater brain volume after three years than those who did not.

Lead researcher Dr Michelle Luciano said: "As we age, the brain shrinks and we lose brain cells, which can affect learning and memory.

"This study adds to the body of evidence that suggests the Mediterranean diet has a positive impact on brain health."

Image copyright Thinkstock Image caption People who follow a Mediterranean diet eat a limited amount of red meat and poultry

Diet accounted for about half the variation in brain volume seen across all the study participants.

The results were the same when researchers adjusted for other factors that could affect brain volume, such as age, education and having diabetes or high blood pressure.

Eating more fish and less meat was not associated with differences between people's brains, contrary to earlier findings.

"It's possible that other components of the Mediterranean diet are responsible for this relationship, or that it's due to all of the components in combination," Dr Luciano said.

Dr Luciano said previous studies carried out measurements in a single "snapshot", while the new research followed participants over time.

She said: "In our study, eating habits were measured before brain volume was, which suggests that the diet may be able to provide long-term protection to the brain. Larger studies are needed to confirm these results.

Cognitive ability

The findings appear in the journal Neurology.

Dr David Reynolds, chief scientific officer at Alzheimer's Research UK, said: "This study adds to previous research highlighting the importance of this kind of well-balanced diet in maintaining a healthy brain as we age.

"While the study points to diet having a small effect on changes in brain size, it didn't look at the effect on risk of dementia. We would need to see follow-up studies in order to investigate any potential protective effects against problems with memory and thinking."

Prof Peter Passmore, professor of ageing and geriatric medicine at Queen's University Belfast, said: "While it would seem that the loss of brain volume over time is not what anyone would want to see and therefore that preservation of volume should be a good thing in terms of cognitive ability, it is still not fully clear exactly what this could mean in terms of memory and dementia.

"The authors do point out that further research is needed."

The study is published in the 4 January online issue of Neurology, the medical journal of the American Academy of Neurology.