Canadian Study Links Ultraprocessed Foods to Children’s Behavioral Development

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When envisioning a typical lunchbox for a Canadian child, what comes to mind? Perhaps a protein-packed Thermos of macaroni and cheese, an English muffin sandwich, some goldfish crackers, and a granola bar?

No matter the assortment, it’s likely that a considerable portion consists of ultraprocessed foods—items that are increasingly dominating the diets of children and recognized as “one of the most urgent yet inadequately addressed threats to human health in the 21st century,” as noted in a recent commentary published in The Lancet medical journal.

Current research is exploring the potential connections between ultraprocessed foods and a variety of health issues, including obesity, diabetes, anxiety, and depression. Recently, Canadian researchers released a new study examining the impact of these foods on a growing concern: childhood behavioral disorders.

Opinion: Not only is food more expensive, it is also becoming ultraprocessed garbage

Published in JAMA Network Open, this new study analyzed data from 2,077 children across Canada, focusing on details of their diets at age 3 and their behavior by age 5.

The Globe and Mail engaged in a conversation with the study’s senior author, Kozeta Miliku, an assistant professor at the University of Toronto, to uncover the findings of this research.

Understanding Ultraprocessed Foods

Everyone’s heard of ultraprocessed foods, but many people aren’t sure how to define them. What exactly is an ultraprocessed food?

That’s a great question, and even we researchers sometimes grapple with it. In simple terms, ultraprocessed foods are industrially formulated items primarily made from refined ingredients and additives that are typically absent in home cooking. This includes sugary drinks, packaged snacks, instant noodles, sweetened cereals, and many ready-to-eat meals.

Surprising Ultraprocessed Foods

What are examples of ultraprocessed foods that might surprise people?

Take packaged bread from the supermarket, flavored yogurt, and most granola bars, for example.

You’ve basically just described my kid’s entire lunchbox.

That’s relatable; many parents feel that way.

Ultraprocessed Food Consumption Among Children

Do we know how much ultraprocessed food Canadian children are eating?

Among preschoolers—specifically three-year-olds—ultraprocessed foods account for nearly half of their daily caloric intake. Upcoming research suggests that this number could soar to 80% for some children, which is quite alarming.

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Connections to Behavioral Issues

There’s been a lot of research into the possible health effects of ultraprocessed foods. But what does the literature tell us about connections with behavioral issues?

This was a key motivator for our study; while there has been considerable focus on the physical and metabolic effects of ultraprocessed foods, understanding their impact on child behavior has received much less attention. Our research is one of the pioneering studies to investigate behavioral outcomes at such an early stage in life.

Findings of the Study

So what did your study find?

Children who consumed higher quantities of ultraprocessed foods showed increased scores for behavioral and emotional difficulties. These included internalizing behaviors, such as anxiety and withdrawal, as well as externalizing behaviors, like hyperactivity and aggression. Our findings also examined the potential benefits of replacing a portion of ultraprocessed foods with minimally processed alternatives, which correlated with improvements in behavioral scores.

While these effects are modest and our study is observational, they do imply that a child’s diet in early years may influence their behavioral development.

Surprises in the Findings

Were you surprised by any of these findings?

Yes, I was particularly surprised that even minor dietary changes could lead to improved behavioral outcomes. Swapping just 150 kilocalories—a replacement for a single granola bar—with whole foods like fruits or vegetables made a notable difference. This underscores the message that small adjustments in children’s diets can foster better behavioral development.

Foods Associated with Behavioral Issues

Were certain foods more tightly associated with behavioral issues?

Indeed, sugary, sweetened beverages were predominantly linked to these behavioral issues. Additionally, we observed that animal-based products and ready-to-eat meals were more closely associated with negative health outcomes.

Understanding the Associations

I know your study doesn’t prove causation, but it suggests something here. Why do you think we might be seeing these associations?

There are multiple potential biological pathways. Ultraprocessed foods often lack fiber and essential nutrients vital for brain function. They might also disrupt the gut microbiome, which interacts with the brain through the gut-brain axis. Furthermore, additives in these foods could promote inflammation or metabolic changes that may affect brain function, though further research is necessary.

Advice for Parents

I’m imagining an exhausted parent reading this article and feeling overwhelmed by the pressure to provide home-cooked meals. What would you say to them?

Parents are doing their utmost. The goal should be progress, not perfection. Instead of striving to eliminate ultraprocessed foods completely—which is nearly impossible—we should focus on increasing whole or minimally processed foods while reducing reliance on packaged snacks. Our research indicates that even a mere 10% substitution can lead to better behavioral outcomes. Commencing with healthier drink options, like making water the default, or swapping one snack for a whole-food choice, can initiate positive changes.

The early years are a critical developmental period for brain growth and the establishment of dietary habits. What children consume during this time can influence their long-term health patterns.

Personal Struggles

You have a four-year-old of your own and are an expert in ultraprocessed foods. Do you find it challenging to navigate this yourself?

Absolutely. I, too, face these challenges and give my child granola bars. Despite my education and resources, the demands of life often pull me towards ultraprocessed foods. Our societal environment makes it difficult to consistently make healthier choices.

This interview has been edited and condensed.