Eating four extra portions of fruit and vegetables each day helps lower the risk of clinical depression and boosts people’s mental health to such an extent that it can offset half the negative psychological impact of divorce and a quarter of the damage of unemployment, new research has found.
The study, Does eating fruit and vegetables also reduce the longitudinal risk of depression and anxiety? is among the few which have found objective evidence linking fruit and vegetables and psychological health.
Co-author Dr Redzo Mujcic, of the Warwick Business School in England, said improved mental wellbeing was significant.
“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,” Dr Mujcic said.
“We found being made unemployed had a very bad and significant effect on people’s mental health, greatly increasing the risk of depression and anxiety. But eating seven or eight portions of fruit and vegetables a day can reduce that by half.
“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.”
Dr Mujcic and co-author Professor Andrew Oswald used data from the Household, Income and Labour Dynamic in Australia (HILDA) survey, which has been undertaken annually since 2001.
In the survey, respondents are asked if they have been diagnosed with depression or anxiety, as well as several questions about their diet and lifestyles.
The study used responses from 7,108 people who said they had not been diagnosed with depression or anxiety in 2007 to see if their diet could predict their chance of depression two years later.
The results revealed the more fruit and vegetables people ate the less likely they were to be diagnosed with a mental illness later on.
“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,” Dr Mujcic said.
“That might not sound much in absolute terms, but the effect is comparable to parts of major life events, like being made unemployed or divorced.”
The authors say the next step is to undertaken a randomised controlled trial to examine the casual relationship between diet and psychological wellbeing in society.