Following a Mediterranean-style diet slows the rate at which the brain shrinks by five years, according to a report by researchers at Columbia University, published in the journal Neurology.

The study indicates that a diet consisting of fruit and vegetables, fish and olive oil but little red meat or dairy products may be associated with losing fewer brain cells due to ageing.

The findings add weight to the theory that a healthy diet can stave off the onset of Alzheimer’s disease by stopping the brain from growing older.

The study shows that people following a Mediterranean-like diet had a larger brain volume than those who didn’t.

Researchers say the difference between the two groups was about the same as five years of ageing.

Study author Doctor Yian Gu, of Columbia University, said: “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.”

The diet in the study included a high intake of vegetables, legumes, fruits, cereals, fish and monounsaturated fatty acids such as olive oil, a low intake of saturated fatty acids, dairy products, meat and poultry, and mild to moderate amounts of alcohol.