New research suggests that mums with unhealthy diets during pregnancy are more likely to have children with behavioural problems. It has also shown that children with unhealthy diets have increased symptoms of depression and anxiety, as well as aggression and tantrums.

Deakin University researchers, working with Norwegian collaborators, have found for the first time that a clear relationship exists between mums’ diets during pregnancy, as well as children’s diets during the first years of life, and children’s mental health.

“We’ve known for quite some time that very 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. But this is the first study indicating that diet is also important to mental health outcomes in children,” said Associate Professor Felice Jacka, lead author of the study and researcher with Deakin University’s IMPACT Strategic Research Centre based at Barwon Health in Geelong.

Depression and anxiety disorders account for some of the leading causes of disability worldwide. Recent research has established that diet and nutrition are related to the risk for these common mental disorders in adults and adolescents. However, no studies have examined the impact of very early life nutrition and its relationship to mental health in children, until now.

This latest study, funded by the Brain & Behavior Research Foundation, involved more than 23,000 mothers and their children participating in the large, ongoing Norwegian Mother and Child Cohort Study (MoBa). The study gathered detailed information on mothers’ diets during pregnancy and their children’s diets at 18 months and three years.

Children’s symptoms of depression, anxiety, conduct disorder and attention-deficit hyperactivity disorder at 18 months, three years and five years of age were reported by parents using well-established questionnaire methods. The relationship of mothers’ diets, and the diets of the children, to the mental health symptoms and behaviours in children over the ages 18 months to five years was then examined, taking into account many other factors that may have explained these relationships.

The results of the study, published in the Journal of the American Academy of Child and Adolescent Psychiatry, suggest that mums who eat more unhealthy foods, such as refined cereals, sweet drinks, and salty snacks, during pregnancy have children with more behavioural problems, such as tantrums and aggression. It also shows that children who eat more unhealthy foods during the first years of their life, or who do not eat enough nutrient-rich foods, such as vegetables, exhibit more of these ‘externalizing’ behaviours, as well as increased ‘internalizing’ behaviours indicative of depression and anxiety. These relationships were independent of other factors that may explain these links, such as the socioeconomic circumstances or mental health of the parents.

Associate Professor Jacka said that as the negative impact of unhealthy foods on the waistline of our population grows, so does the evidence suggesting that our mental health is also affected.

“It is becoming even more clear that diet matters to mental health right across the age spectrum,” she said.

“These new findings suggest that unhealthy and ‘junk’ foods may have an impact on the risk for mental health problems in children and they add to the growing body of evidence on the impact of unhealthy diets on the risk for depression, anxiety and even dementia.

“The changes to our food systems, including 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 right across the globe.

“There is an urgent need for governments everywhere to take note of the evidence and amend food policy to restrict the marketing and availability of unhealthy food products to the community,” Associate Professor Jacka said.

As released by Deakin University, 20 August 2013