Study Links Regular Soft Drink Consumption to Changes in Teen Brains

Consuming as few as two cans of soft drinks per week may lead to detectable changes in the brains of children aged nine to eleven, according to a study from King's College London. The research, which analyzed data from the U.S.-based Adolescent Brain Cognitive Development (ABCD) study, found associations between caffeine consumption and subtle differences in brain structure, sleep duration, and later mental health outcomes.

Researchers examined weekly caffeinated drink intake, including coffee, tea, and soft drinks, along with parental reports on children's sleep patterns. Brain scans were used to measure the thickness and surface area of the cerebral cortex, the brain's outermost layer responsible for cognitive functions. The study observed these children for up to 18 months, noting emotional and behavioral problems.

The findings indicated that greater caffeine consumption was linked to smaller surface areas in several brain regions, with effects appearing even in children consuming just one caffeinated drink weekly. Those who consumed more caffeine also tended to sleep less and reported more emotional and behavioral difficulties, including signs of anxiety and depression. Previous research has established a link between insufficient sleep and negative impacts on concentration, academic performance, and mental health.

While energy drinks have been a focus of concern regarding caffeine in young people, this study highlights that popular soft drinks also contain significant amounts of caffeine. For instance, a can of Diet Coke contains approximately 46mg of caffeine, and a bottle of Mountain Dew contains about 54mg. The study's lead author, neuroscientist Professor Divyangana Rakesh, noted that caffeine is so common in daily life that its consumption by young people often goes unnoticed and is currently unregulated in many soft drinks.

It is important to note that the researchers stressed their findings do not definitively prove caffeine directly causes these changes. The study acknowledged that many soft drinks are also high in sugar and often consumed as part of broader lifestyle habits that could influence health outcomes. Jiayi Zheng, the study's first author, stated that isolating the precise effects of caffeine from sugar and other lifestyle factors is a subject for future research.

Experts not involved in the study pointed out that the observed differences in brain activity were small, and the association with later mental health was described as negligible. However, they agreed with the robust conclusion that caffeine can reduce sleep duration in children. Current regulations in the UK, set to take effect in April 2027, will make it illegal for children under 16 to buy energy drinks containing more than 150mg of caffeine per liter, a measure the study's authors suggest may not go far enough.