It looks like the key to well-behaved children begins even before a baby is born, as a new study on the impact of pre-natal nutrition reveals that moms with unhealthy diets are far more likely to have children with mental as well as physical health issues, the Daily Mail reports.

Researchers from Deakin University in Melbourne, Australia and Norway collaborated on the latest study funded by the Brain & Behavior Research Foundation that involved more than 23,000 mothers and children, as part of the larger, ongoing Norwegian Mother and Child Cohort Study. Researchers collected details of the mothers' diets during their pregnancy as well as the diets of their children at 18 months and three years using a series of questionnaires. Data was also collected about the behavior of the children at 18 months, three years and five years.

The results they uncovered revealed some disconcerting but important findings for potential parents.

"Early life nutrition, including the nutrition received while the child is in utero, is related to physical health outcomes in children - their risk for later heart disease or diabetes for example," wrote associate professor Felice Jacka, researcher with Deakin University's IMPACT Strategic Research Center and lead author of the study. "But this is the first study indicating diet is also important to mental health outcomes in children. It is now more clear than ever that diet matters to mental health right across the age spectrum."

Children surveyed at 18 months, three years and five years were evaluated for conduct disorders, depression, anxiety and ADHD. Children who exhibited symptoms of mental health disorders were far more likely to have had mothers who ate poorly while pregnant.

In order to determine a clear relationship between a mother's diet and her child's health, socioeconomic factors and the mental health of the parents were not included as part of the research. 

"There is an urgent need for governments everywhere to take note of the evidence and amend food policy," Jacka wrote. "The shift to more high-energy, low nutrition foods developed and marketed by the processed food industry, have led to a massive increase in obesity-related illnesses everywhere. They must restrict the marketing and availability of unhealthy food products to the community."

Jacka's past studies on nutrition and mental health have suggested a similar link between poor diet and mental health issues, though her latest study is the first to tackle the impact of early-life nutrition on the mental health of children.

The new study is published in the journal American Academy of Child and Adolescent Psychiatry.