Unhealthy snacks drive disruptive behavior in young children

Researchers at the University of Agder (UiA) have already identified clear links between what children eat and their mental health as early as the age of four.

Children who eat plenty of fruit and vegetables show fewer signs of anxiety and restlessness. Those who eat a lot of sweet and salty foods display more disruptive behavior.

There is such a clear link between what we eat and how we feel, both physically and mentally, that we need to talk more about it." 

Professor Nina Cecilie Øverby at UiA

Together with her colleagues Christine Helle and Elisabet Rudjord Hillesund, she has studied the diet and behavior of 363 Norwegian four-year-olds.

More fruit, fewer difficulties

"There are quite a few studies on the link between diet and mental health, but most of them focus on adolescents and adults. For children as young as these, the evidence base has been limited", says Hillesund.

The parents in the study reported how often their children ate various foods. At the same time, the children's behavior was assessed using a questionnaire that measures two types of difficulties: internalising behavior such as anxiety, sadness and withdrawal, and externalising behavior such as anger, restlessness and concentration difficulties.

"The more often the children ate fruit and vegetables, the lower their scores were on both types of behavioral problems", says Helle.

Children who ate a lot of sweet and savoury snacks showed more signs of disruptive behavior.

"The effect of unhealthy food was actually stronger than the protective effect of fruit and vegetables", says Hillesund.

Several explanations

Why are diet and mental health linked even at nursery age? Researchers point to several possible explanations.

On the one hand, fruit and vegetables contain nutrients such as antioxidants, folate and minerals. These can help protect the brain against inflammation and oxidative stress. Sweets and fats, on the other hand, can negatively affect the brain's plasticity in areas that are important for mental health.

But the explanation may also lie in the meal itself.

"Vegetables are often something we eat for dinner. Shared family meals are important for the quality of our diet, but also for quality of life and well-being", says Øverby.

Cause and effect

The study is a cross-sectional study. This means that the researchers have a snapshot in time and cannot say with certainty what is cause and what is effect.

"It is conceivable that it is more tempting for parents to give sweets to a demanding child, whether to comfort them or to give in to their nagging", says Hillesund.

Nevertheless, the researchers believe it is most likely that diet is what influences the children. They have adjusted for several factors that might otherwise explain the correlation, including the family's financial situation and the parents' education.

"The mother's mental health is an important factor in how the children feel about themselves, but we have also taken that into account," says Helle.

Food as prevention

Mental health issues are a major health challenge in society. Among teenagers in Norway, around one in five girls and one in ten boys experience high levels of mental distress. Research suggests that problems that arise at an early age often continue to affect the child later in life.

"It's important to intervene early and prevent this," says Helle.

The researchers believe the findings support the public health work already being done, but also point out that more should be done. They highlight meals in nursery schools, dietary guidance at health clinics, support for parents and training for teachers.

"When we talk about a healthy diet, it's often in the context of avoiding cardiovascular disease when we're sixty. But diet matters for our mental health right here and now. Children need to be social, develop, learn and interact with others. We don't want what they eat to stand in the way of this," says Øverby.