It turns out the recommendation for children to get at least five servings of fruits and vegetables per day can impact more than their physical health. Researchers from the University of East Anglia found school kids who ate a diet high in fruits and vegetables had better mental health than their peers who ate less.

Researchers studied the impact of breakfast and lunch choices on the mental wellbeing of UK school children and discovered a strong correlation between fruit and vegetable intake and mental health. The link was most evident among secondary school children where those who ate five or more servings per day scored the highest.

"We know that poor mental wellbeing is a major issue for young people and is likely to have long-term negative consequences," said lead researcher Ailsa Welch. "The pressures of social media and modern school culture have been touted as potential reasons for a rising prevalence of low mental wellbeing in children and young people. And there is a growing recognition of the importance of mental health and wellbeing in early life—not least because adolescent mental health problems often persist into adulthood, leading to poorer life outcomes and achievement."

The study organizers are hoping the information can be used to ensure good quality nutrition is available for all children before and during school to help children thrive.

"While the links between nutrition and physical health are well understood, until now, not much has been known about whether nutrition plays a part in children's emotional wellbeing," Welch said. "So, we set out to investigate the association between dietary choices and mental wellbeing among schoolchildren."

The study involved nearly 9,000 school children Norfolk County England with the majority being secondary students. Children were surveyed on their food intake and also completed age-appropriate tests for mental wellbeing. They were scored on things such as cheerfulness, relaxation and having good interpersonal relationships.

"Children who ate a traditional breakfast experienced better wellbeing than those who only had a snack or drink," said Dr. Richard Hayhoe, from UEA's Norwich Medical School. "But secondary school children who drank energy drinks for breakfast had particularly low mental wellbeing scores, even lower than for those children consuming no breakfast at all."

Researchers also factored into their findings the impact outside influences such as childhood experiences and home situations had on the wellbeing scores.

"According to our data, in a class of 30 secondary school pupils, around 21 will have consumed a conventional-type breakfast, and at least four will have had nothing to eat or drink before starting classes in the morning," Hayhoe said. "This is of concern, and likely to affect not only academic performance at school but also physical growth and development. Another interesting thing that we found was that nutrition had as much or more of an impact on wellbeing as factors such as witnessing regular arguing or violence at home."

Click here to read more in the journal BMJ Nutrition, Prevention & Health.