Interestingly, eating five portions of fruit and four portions of vegetables daily was enough to reach the peak of happiness.Aproximando Ciênciae/Flickr

Regular consumption of fruits and vegetables can help improve mental health, an Australian study says.

Interestingly, eating five portions of fruits and four portions of vegetables daily was enough to reach the peak of happiness.

For the study, researchers from the University of Queensland looked at 12,000 people, aged between 15 and 93, as part of the annual Household, Income, and Labour Dynamics Australia (HILDA) Survey. The participants answered questions related to their lifestyle, eating habits and health -- both mental and physical. They also rated their level of happiness and also provided details about the total daily intake of fruits and vegetables.

Women benefitted the most from eating fruits and vegetables. Including more fruits to the daily diet provided the best psychological effects than vegetables.

"It comes up the more you eat the better, but there's also some optimal points," Dr Redzo Mujcic from UQ's school of pharmacy, told 612 ABC Brisbane. "Eating about five fruits and five vegetables [per day] makes us the happiest we can be in that case."

However, the study also found that only a minority of the Australian population -- to say less than 25 percent -- received the recommended level of fruits and vegetables needed daily.

Similarly, role of vegetables and fruits in physical health is well-known. Another study from Australia released early this year showed that unhealthy food habits increased the risk of many chronic diseases. In the June study, higher intake of fruits prevented onset of first chronic disease while inclusion of more vegetables provided protection against risk of having more than one chronic disease.

Eating fruits and vegetables is also good for keeping different organs healthy, including eyes and heart.

These findings back a World Health Organisation (WHO) report that linked intake of 400 g of fruit and vegetables a day to lowered risk of chronic diseases including diabetes, obesity and cancer. They also attributed 1.7 million deaths across the world to insufficient consumption of fruits and vegetables.