Daily Soda May Be Shaping Young Brains, Study Finds

Shaping Young Brains may begin with a single caffeinated drink a week. New research on 9,632 children found that even that small amount was linked to slightly smaller surface area across the brain's outer layer — with shorter sleep playing its own role along the way.

The study, led by researchers at the Institute of Psychiatry, Psychology and Neuroscience at King's College London and published in October 2026, drew on the Adolescent Brain Cognitive Development study, a long-running project tracking brain development in young people across the United States. The children, ages nine to eleven, reported how many caffeinated drinks they usually had each week — coffee, tea or soft drinks — while parents reported typical sleep duration. MRI scans then measured the thickness and surface area of the cortex, the folded outer layer involved in attention, decision making and emotion. About six and eighteen months later, the kids reported back on their mental health.

The pattern was strikingly consistent. Greater caffeine consumption was associated with lower cortical surface area in twenty-two separate regions spanning all four lobes of the brain, and the link held even after adjusting for household socioeconomic circumstances such as parental education and income. Soft drinks were the biggest source of caffeine in the group, and differences showed up from as little as one caffeinated drink a week compared with none at all, according to Technology Networks.

Shorter sleep may be the bridge

Shaping Young Brains, in this study, ran through shorter sleep. Young people who consumed more caffeine slept less, and that shorter sleep was in turn linked to lower surface area. Together, the two factors partly explained the link between higher caffeine intake and more mental health difficulties at the half-year check-in, including problems with attention, mood and behaviour. By the eighteen-month follow-up, only the pathway through overall surface area was still detectable.

The study's senior author, Dr Divyangana Rakesh, put the blind spot plainly: "Caffeine is such a normal part of daily life that it's easy to forget young people are consuming it too." Her team estimates that two-thirds of adolescents take in caffeine at least once a week. "Despite it being a psychoactive substance, it is completely unregulated," she added. First author Jiayi Zheng was careful about what the data cannot say: the team could not separate caffeine itself from the sugar and lifestyle habits that travel with soft drinks. "We can't yet separate the role of caffeine from everything else that comes with them," Zheng said — the next step is measuring precisely what young people drink, when they drink it, and how well they sleep.

Why this lands for teens anyway

The participants were children, but the habits in question belong to teenagers. Caffeine use tends to ramp up, not down, through the teen years — energy drinks, iced coffee, pre-workout powders — and the sleep pathway the study identified is exactly the one adolescents already struggle with. If shorter sleep is the bridge between caffeine and the brain differences, then the late-night can before a school day matters more than the molecule in isolation.

Regulators are already moving. In the United Kingdom, a forthcoming ban will block sales of energy drinks containing more than 150 milligrams of caffeine per litre to young people, and the public health minister has said plainly that high-caffeine energy drinks have no place in children's hands, according to Ghana MMA's coverage of the findings. Independent experts urge calm, though. A professor of digital health at University College London noted the study captured brain imaging at only a single timepoint and that sleep and mental health were reported by children and parents rather than assessed by clinicians — reasons to treat the results as a signal worth following, not a verdict.

What to actually do with this

First, the honest caveat: this is a correlation, not proof that caffeine causes the differences. The researchers say so themselves. But the practical takeaways do not require certainty. If you drink caffeine, the sleep connection is the part you control: an afternoon cutoff protects the deep, early-night sleep your brain uses for recovery, and swapping the late-day soda for water removes both the caffeine and the sugar load that muddied the study's data. For parents, the finding reframes the question from "is coffee bad?" to "what is this drink displacing?" — because a habit that shortens sleep is doing its damage through the lost rest, not just the buzz.

The bigger picture is about timing. Shaping Young Brains is a slow process, and the brains in question keep developing well into the mid-twenties — so small structural differences linked to weekly caffeine in childhood may compound if the habit, and the short sleep, persists for a decade. Nobody needs to panic over a morning latte, but the era of treating caffeine as consequence-free fuel is ending. If sleep is the foundation everything else rests on, as researchers keep finding in weekend sleep research and studies on daily movement and deeper rest, then guarding your sleep is the highest-leverage health habit you own.