A survey by Australia in 2016 found improvements in psychological well-being after increasing consumption of fruit and vegetables. We wanted to know whether this discovery was true by using a larger sample (more than 40,000 participants) of the UK household survey
. Our analysis showed that increasing consumption of fruit and vegetables is associated with increasing self- the psyche of well-being and life satisfaction in data covering a five-year period, even after taking into account other determinants of mental well-being such as physical health, income and consumption of other foods.
The benefits of physical activity for mental health are well established. Estimates from our work show that adding one serving to your diet a day can be as beneficial to mental well-being as a walk with additional seven to eight days a month. One serving is equal to one cup of raw vegetables (fist size), half a cup of boiled vegetables or chopped fruit or one piece of whole fruit. This result is encouraging, as it means that one of the possible ways to improve your mental health can be something as simple as eating an extra piece of fruit every day or eating a salad.
It is important to emphasize that our discoveries alone can not reveal a cause and effect relationship between fruit and vegetable consumption and increased psychological well-being. And we can not rule out the so-called "substitution effects". People can eat so much in just one day, so someone who eats more fruits and vegetables may just have less space in their diet for unhealthy foods. Although in our study we look at bread and dairy products, ideally future research should track all other foods consumed to exclude alternative explanations.
But when taken in conjunction with other studies in this area, the evidence is encouraging. For example, a randomized study conducted in New Zealand found that various measures of mental well-being such as motivation and vitality improved in a treatment group where young people were asked to eat two extra portions of fruit and vegetables a day for two weeks, although no changes were found for depressive symptoms, anxiety or mood.