New research on caffeine and the young brain shows how soda and energy drinks could hinder a child’s development.

Caffeine is readily available in products—everything from gum to energy drinks—marketed to children and young adults. However, the long-term effects of caffeine, especially on young people, are still largely unknown.

We know caffeine can affect sleep, of course. Grownups often drink it because it can aid alertness. But when it affects children’s sleep—which mounting evidence says is critical for brain development—it can really hold them back.

A new study in the journal PLOS ONEconcerns caffeine consumption in pubescent lab rats. Researchers found that young rats who consumed the rat-sized equivalent of the caffeine in three or four cups of coffee daily experienced reduced deep sleep and delayed brain development.

Caffeine impacts development by disrupting the formation of key connections in the brain, said study author Dr. Reto Huber, a sleep expert at the University of Zurich, and others at the University of Zurich Children’s Hospital. During adolescence, your brain has the most neural connections it will ever have during your lifetime.

“The brain of children is extremely plastic due to the many connections,” Huber said in a statement accompanying the research. “This optimization presumably occurs during deep sleep. Key synapses extend, others are reduced; this makes the network more efficient and the brain more powerful.”

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The Zurich research team administered doses of caffeine to 30-day-old rats over five days and measured the electrical impulses in their brains. The rat’s slow brain waves during the deepest phase of sleep were reduced from day 31 until day 42, or nearly a week after they stopped receiving caffeine.

Compared with rats given only water, the caffeinated rats had fewer neural connections, and this affected their behavior: rats, like children, become more curious with age, but the rats given caffeine remained timid and cautious.

As the brain develops, cells begin to make connections to solidify things the mind deems important. When that process is disrupted, problems can arise. Huber cautions parents to monitor the amount of caffeine given to their children and teens.

The National Sleep Foundation recommends that school-aged children get at least 10 hours of shut-eye a night.

A study in the journal Nutrition Research shows that every 10 milligrams of caffeine a 13-year-old boy drinks per day increases his chances of getting less than 8.5 hours of sleep by 12 percent.

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Eight ounces of the typical commercial energy drink—such as Red Bull or Monster—contains 76 to 80 milligrams of caffeine, a 12-ounce Mountain Dew has 55 milligrams, and a two-ounce 5-Hour Energy drink contains 207 milligrams, according to the Mayo Clinic.

All parents know that their children don’t sleep well if they’re jacked up on caffeine. But a larger concern is that the sleep they miss out on could keep them from reaching their academic potential.