An extra serving of fruit linked to lower risk of depression and anxiety in teenagers

The food choices teenagers make could have implications beyond their physical health, with new research from the University of Sydney linking food choices and sugar consumption to the later emergence of depression and anxiety symptoms.

Published in Child and Adolescent Mental Health, the study followed 6,537 adolescents from 71 secondary schools across New South Wales, Queensland and Western Australia from seventh to 10th grade. Participants were 12.5 years old on average at the start of the study and completed annual surveys over four years during high school.

Researchers found that eating one additional serving of any type of fruit each day was associated with a 13% lower risk of depression symptoms and a 7% lower risk of anxiety symptoms over the study period. Average fruit consumption ranged from 2 to 2.5 servings a day across the study period.

Higher consumption of sugar-sweetened drinks, including soft drinks, sweetened drink concentrates and sports drinks, was associated with an increased risk of depression and anxiety. The association with sugary drinks was observed in male and female teenagers, but was stronger in males, particularly for anxiety.

Lead author Dr. Lily Davidson, a postdoctoral research associate at the University of Sydney’s Matilda Centre for Research in Mental Health and Substance Use, said adolescence was an important time to investigate the relationship between food and mental health.

“High school is a time when young people start gaining much more independence over what they eat and drink, at the same time as many mental health problems start to emerge,” she said.

“We’re not saying eating an apple will prevent depression, or that having a soft drink will cause anxiety—mental health is far more complex than that. But what you eat is one part of a young person’s life that can potentially be changed, which makes these findings important from a prevention angle.”

Tracking teen mental health over time

Much of the previous research linking adolescent dietary intake and mental health has taken a snapshot in time, making it difficult to establish which came first. Using data from the Matilda Centre’s Health4Life study, researchers instead followed teenagers for three years and excluded adolescents who already met the relevant threshold for depression or anxiety at the beginning of the study.

“One of the big questions in our field is whether poor nutrition comes before mental health problems, or whether young people experiencing poor mental health simply eat differently,” Davidson said.

“By starting with adolescents who weren’t already experiencing elevated symptoms and following them through high school, we could look at whether their dietary intake was associated with the later emergence of those symptoms.”

Participants reported their usual daily fruit and vegetable intake and their consumption of sugar-sweetened beverages. The researchers also accounted for factors including physical activity, age, sex and socioeconomic status.

Bringing the school cafeteria into the mental health conversation

The findings come amid growing efforts to understand what can be done before young people develop significant mental health problems, rather than intervening only once symptoms appear.

“It’s easy to think of food and nutrition as being about physical health, but our findings add to evidence that what young people eat may also matter for their mental health,” Davidson said.

“We need to understand what makes healthy choices easy or difficult for teenagers and make healthy eating a priority in adolescent mental health prevention.”

Associate professor Katrina Champion, senior author on the study and a Sydney Horizon fellow at the Matilda Centre and the Brain and Mind Centre, said, “Creating environments that make nutritious foods more accessible and affordable for families and reducing young people’s exposure to sugary drinks move the conversation away from telling a teenager to eat better and toward addressing the environments that shape their choices.

“Schools, families and governments all have a role to play in supporting healthy behaviors and better mental health for young people,” she said.

Who’s behind this story?

Swati Mestri

Swati Mestri holds a bachelor’s degree in Electronics Engineering and has worked as a content editor since 2019. She has experience editing research documents across technology, health care, and materials science, and has a particular interest in technology and space.

Full profile →

Andrew Zinin

Master’s in physics with research experience. Long-time science news enthusiast. Plays key role in Science X’s editorial success.

Full profile →