A Mediterranean-style diet could slow the ageing process in the brain by up to five years, a new study has shown.

While not conclusive, research by neuropsychologists at New York University has suggested that eating plenty of vegetables, fish, pulses and olive oil - and laying off the red meat and dairy products - keeps the brain youthful.

The findings published by The Guardian showed that of 674 people aged over 80 in Manhattan who did not have dementia, those who followed a typically Mediterranean diet had a brain volume on average 13.11 millilitres greater than those who did not.

"These results are exciting, as they raise the possbility that people may potentially prevent brain shrinking and the effects of ageing on the brain simply by following a healthy diet," the lead author of the study, Yian Gu of New York University, told The Guardian.

Although the difference in brain volume between those who did and did not eat a Mediterranean-style diet was relatively small, it equated to about five years of ageing, said the authors of the study.

The diet is known to be rich in plant-based foods such as vegetables, fruits, legumes, whole grains and nuts, as well as fish and monounsaturated fatty acids like olive oil. Spices and herbs are often used to flavour food instead of salt.

In particular, eating fish often - ideally three to five ounces a week - and no more than 3.5 ounces of red meat a day "may provide considerable protection against loss of brain cells equal to about three to four years ageing," said Professor Gu.

The authors did warn that their findings show an association between a Mediterranean diet and a healthy brain, but do not conclusively prove that such a diet definitely prevents brain shrinkage.

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