Researchers at King’s College London analysed data from 9,632 children aged nine to 11 who participated in the US‑based Adolescent Brain Cognitive Development study and found that higher weekly caffeine consumption, largely from soft drinks, was linked to shorter sleep duration and a slightly smaller cortical surface area.

The reduced cortical surface area was observed across 22 regions spanning all four brain lobes and persisted after adjusting for family income and parental education.

Even consumption as low as one caffeinated drink per week was associated with a modestly smaller overall brain surface area compared with children who consumed none, though the authors stress this does not prove causation.

Higher caffeine intake was also linked to more mental‑health problems six months later, including difficulties with attention, mood and behaviour, a relationship partly explained by reduced sleep.

Shorter sleep itself correlated with the smaller cortical surface area, underscoring the importance of adequate rest for children’s cognitive and emotional development.

Parents are advised to read beverage labels, limit children’s access to caffeinated soft drinks, encourage water or caffeine‑free alternatives, and maintain regular bedtime routines to support sleep and brain health.