Increasing the amount of fruit and vegetables people eat lowers their risk of clinical depression, new research has found.

The study discovered that eating, for example, four extra portions of fruit and vegetables a day can boost people’s mental health. This is one of only a few studies that has found objective evidence of the association between fruit and vegetables and psychological health.

Redzo Mujcic, of Warwick Business School, author of the paper alongside Andrew Oswald, of the University of Warwick, said: “This is an interesting finding and makes the case for an empirical link between fruit and vegetables and improved mental wellbeing more powerful.

“The effect is not small as well. If people eat around seven or eight portions of fruit and vegetables a day the boost in mental wellbeing is as strong as divorce pushing people the other way, to a depressed state. And the effect is a lot quicker than the physical improvements you see from a healthy diet. The mental gains occur within 24 months, whereas physical gains don’t occur until you are in your 60s.

“If people increase their daily intake of fruit and vegetables from zero to eight they are 3.2 percentage points less likely to suffer depression or anxiety in the next two years,” said Dr Mujcic.