Childhood experiences can shape health in ways that take years to show up. New research suggests that, for some young people, behavior problems during adolescence may be one link between childhood trauma and later eating habits.
Researchers followed 4,229 young people in Brazil from childhood into early adulthood. They found that greater exposure to potentially traumatic events in childhood was linked to more behavior problems at age 15, including impulsivity, hyperactivity and conduct problems. Those problems were then associated with a higher share of calories from ultraprocessed foods at age 18. The study does not show that trauma directly caused those eating habits.
The study, published in the Journal of Child Psychology and Psychiatry, used data from the 2004 Pelotas Birth Cohort, which has followed children born in the southern Brazilian city of Pelotas from birth through adolescence and young adulthood.
That long-term design is an important strength. Rather than asking adults to remember childhood experiences years later, researchers collected information as the participants grew up.
By age 11, about 34% of participants had experienced at least one potentially traumatic event, including things such as maltreatment, assault, serious accidents or disasters.
At age 15, caregivers reported on two broad types of mental health problems. One involved inwardly directed symptoms, such as emotional or peer problems. The other involved outwardly expressed behaviors, such as conduct problems, hyperactivity and impulsivity.
At age 18, the young people completed a food questionnaire that allowed researchers to estimate what percentage of their calories came from ultraprocessed foods. On average, those foods made up about 29% of calorie intake.
The clearest pattern involved the outwardly expressed behavior problems.
Young people with more of those problems at age 15 tended to get a larger share of their calories from ultraprocessed foods at age 18. The same pattern was not seen for inwardly directed symptoms such as anxiety or emotional distress.
The researchers then looked at whether those behavior problems might help explain the connection between earlier trauma and later eating habits.
They estimated that outwardly expressed behavior problems accounted for about 17% of the overall link between childhood trauma and ultraprocessed food intake. In other words, behavior problems appeared to be part of the picture, but most of the connection remained unexplained.
That is an important distinction. The results do not mean that children who experience trauma will inevitably eat more ultraprocessed foods later, or that impulsivity is the main reason these eating patterns develop.
The researchers suggest that difficulties with self-control and reward-seeking may play a role, but the study did not directly test those mechanisms. Other factors, including family circumstances, social conditions and biology, may also contribute.
The study also does not show that ultraprocessed foods themselves caused later health problems in these participants. Researchers used intake of those foods as one of several health-related behaviors that may be linked to future cardiometabolic risk. They did not measure whether the participants developed heart disease, diabetes or other metabolic conditions.
The diet finding was modest, too. The authors noted that the overall links between childhood trauma and the later health behaviors they studied were generally small.
That nuance matters with ultraprocessed food research because the category includes a wide range of foods. This study looked at the percentage of calories coming from that broad category rather than judging the nutritional quality of every individual food.
The researchers also found links between childhood trauma, adolescent behavior problems and later smoking, illicit drug use and problematic alcohol use. Unexpectedly, the same behavior problems were also associated with more physical activity.
That mixed pattern is one reason the researchers caution against viewing adolescent behavior problems as simply “good” or “bad” for health. The same traits may be connected with different behaviors in different ways.
“Interventions that help trauma-exposed youth regulate their emotions and behaviours better could have benefits beyond reducing mental health difficulties,” lead author Dr. Sophie Townend said in the news release.
The study has several strengths, including its large birth cohort and repeated measurements across childhood and adolescence. Researchers also measured physical activity with wearable devices rather than relying only on participants’ memories.
There are also important limitations. About half of the participants were missing age-15 data, largely because COVID-19 disrupted data collection. Researchers used statistical methods to account for the missing information, but some uncertainty remains. Mental health symptoms were reported by parents, who may be more likely to notice outward behavior than internal emotional struggles. The trauma measure also recorded whether events occurred, but not how severe or long-lasting they were or how the young person experienced them.
The Pelotas cohort and its follow-up studies received support from several public and nonprofit sources, including the Wellcome Trust, World Health Organization, Brazilian Ministry of Health, Brazilian National Research Council, São Paulo Research Foundation and other Brazilian research agencies. The current analysis was funded by the U.K. Economic and Social Research Council and the São Paulo Research Foundation.