One can of cola a week. That was enough for researchers in London to spot differences in how much children slept and which part of the brain got affected.
A study from King’s College London was published in the journal Biological Psychiatry: Cognitive Neuroscience and Neuroimaging and looked at 9,632 U.S. children aged 9 to 11.
How The Study Worked
According to the study, the kids who were part of it had a big, long-running project that follows brain growth in young people across the country. Each child said how many caffeinated drinks he or she usually had in a week.
Parents reported how long their children slept. MRI scans measured the surface area of the cortex, the folded outer layer of the brain.
Children with more caffeine in their week slept less. Their cortical surface area was also slightly smaller, in an area that helps with attention, decision-making and emotions.
The gap appeared at one drink a week compared with none. Most of the caffeine came from soft drinks. Coffee and tea made up the rest.
The researchers checked back with the children 6 months and 18 months later. Kids who reportedly had more caffeine also reported more trouble with attention, mood and behavior.
Shorter sleep, the team believed, may account for part of that.
How Sleep Is Connected to Caffeine
Caffeine can get in the way of adenosine, a chemical that builds up during waking hours and makes people feel tired. Block it, and bedtime gets harder.
For children, that matters because the brain does a lot of its sorting and strengthening while they sleep.
Divyangana Rakesh, the study’s senior author, said it’s “easy to forget young people are consuming it too.”
She pointed to earlier research suggesting that about two-thirds of adolescents have caffeine at least once a week. She noted that caffeine affects the brain yet isn’t regulated.
What Parents Should Know About Caffeine
The study only observed children. It reportedly can’t show that caffeine caused the brain differences or the mood and behavior problems. Because so much of the caffeine came in sweetened drinks, sugar may be playing a part.
Screen time at night or what a child eats the rest of the day could also count. The authors admitted that more research is needed.
If your child seems tired all the time, has a hard time focusing or is more irritable than usual, parents are advised to bring it up with a pediatrician. Caffeine may be part of the picture.
