Children who are exposed to “junk food” before birth and during early childhood are at a significantly increased risk for developing mental health problems — including anxiety and depression — while still very young, according to a new study by researchers from Deakin University in Melbourne, Australia.
Researchers found that a greater consumption of unhealthy food during pregnancy, as well as a lack of healthy food in children during the first years of life, was tied to higher levels of behavioral and emotional problems.
“This study comes from the largest cohort study in the world and is the first to suggest that poor diet in both pregnant women and their children is a risk factor for children’s mental health problems,” said lead investigator Felice Jacka, Ph.D.
Several studies by Jacka and her research team, as well as other research groups, have demonstrated a strong link between mood and food. One of Jacka’s previous studies showed that food has a significant effect on mental health and may play a role in the prevention and treatment of common mental disorders such as depression and anxiety in teens.
Other studies have had similar results, showing a link between diet quality and adult mental health. However, the researchers emphasize that maternal and early postnatal nutrition and its effects on children’s subsequent mental health have not been explored.
The new study involved 23,020 women and their children who were a part of the Norwegian Mother and Child Cohort Study (MoBa). Information was received through self-report questionnaires sent to mothers at 17 weeks’ pregnancy and in later pregnancy and at intervals after birth when children were aged 6 months, 1.5 years, 3 years, and 5 years.
Researchers provided a 225-item food frequency questionnaire (FFQ) to the pregnant women, developed specifically to capture the dietary habits and intake of dietary supplements during the first 4 to 5 months of pregnancy.
Participants were then categorized into 2 major dietary patterns — a “healthy” pattern, characterized by high intake of vegetables, fruit, high-fiber cereals, and vegetable oils, and an “unhealthy” pattern, characterized by a high intake of processed meat products, refined cereals, sweet drinks, and salty snacks.
The children’s diet was assessed using a 36-item FFQ which included dietary items on types of foods and drinks such as dairy products, cereal-based porridge, and fruit juice.
The researchers used another checklist to assess internalizing problems, including anxiety and depression, and externalizing behaviors, such as attention-deficit/hyperactivity disorder, oppositional defiant disorder, and conduct disorder.
The findings revealed that pregnant moms who ate more unhealthy foods were significantly more likely to have children with more behavioral problems, such as tantrums and aggression.
Furthermore, children who ate more unhealthy foods in early life or who did not eat sufficient amounts of nutrient-rich foods during the first years of life exhibited more of these “externalizing” behaviors as well as increased “internalizing” behaviors, such as depression and anxiety.
“In this study, we report highly novel data suggesting that maternal and early postnatal dietary factors play a role in the subsequent risk for behavioral and emotional problems in children,” said the researchers.
“Both an increased intake of unhealthy foods and a decreased intake of nutrient-rich foods in early childhood were independently related to higher internalizing and externalizing behaviors in young children. These behaviors are established early markers for later mental health problems.”
Jacka also noted that the average age of onset for anxiety disorders is only 6 years; for depression, it is 13 years. Because of this, she said, this study has “profound” public health implications, particularly with respect to the fast-food industry.
“We’ve known for 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 may also be important to mental health outcomes in children,” Jacka said.