The biological age of our brains is a health factor that many people neglect – but as young people these days are expected to live longer than ever, it’s getting more and more important.

 It turns out that switching to a diet full of fresh vegetables and low in processed foods could do wonders for what’s going on up there, new research has found.

 According to a team of scientists from universities in Israel, Germany and the US, eating a Mediterranean diet rich in vegetables, seafood and whole grains can slow the signs of accelerated brain ageing which are typically seen in obese patients.

 Scans taken after 18 months showed the participants’ brain age appeared almost nine months younger than expected, compared to estimates of their brain’s chronological age.

The study involved imaging the brains of 102 people who were taking part in a larger clinical trial. Scans were taken at the beginning, and again after 18 months, along with tests of liver function, cholesterol levels and body weight.

 Groups ate one of three diets: a Mediterranean diet of nuts, fish and chicken instead of red meat, a similar diet but with a few added extras like green tea, or a diet based on healthy dietary guidelines.

 Brain age estimates were based on an algorithm that had been trained using brain scans from a separate group of nearly 300 people.

 People in the trial lost an average of about 2.3kg. For every 1 percent of body weight lost after following a set diet, the participants’ brains appeared about nine months younger than their chronological age.

 However, it is still unknown whether changes in brain age actually translates to improvements in brain function.

 "Our study highlights the importance of a healthy lifestyle, including lower consumption of processed food, sweets, and beverages, in maintaining brain health," said neuroscientist Gidon Levakov of Ben-Gurion University of the Negev in Israel.

 The study was published in eLife.