The foods can offset the impact of major life events, like divorce and unemployment.
Eating more fruits and vegetables is linked to a lower risk of depression new research concludes.
An extra four portions of fruit and vegetables per day can offset the impact of major life events, like divorce and unemployment.
The boost from more fruit and vegetables could counteract half the pain of getting divorced or one-quarter that of being unemployed.
The effect on mental well-being of eating 8 portions per day compared with none is even more dramatic.
These benefits come on top of the well-known protective effect against cancer and heart disease.
The conclusions come from an Australian survey of 7,108 people carried out every year since 2001.
All were asked about their diet and lifestyle.
The results showed that the more fruit and vegetables people ate, the less likely they were to be diagnosed with mental health problems later on.
Dr Redzo Mujcic, the study’s first author, said:
“If people eat around seven or eight portions of fruit and vegetables a day the boost in mental well-being is as strong as divorce pushing people the other way, to a depressed state.
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.”
One possible mechanism by which fruit and vegetables affect happiness is through antioxidants.
Dr Mujcic said:
“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.
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.
We tested for reverse-causality—ie whether it might be that depression or anxiety leads to people eating less fruit and vegetables—but we found no strong statistical evidence of this.”