Young kids seem to have boundless energy. The colorings and preservatives in soft drinks, candy, and other foods can boost kids’ activity levels higher still, a new study finds. This increase fosters hyperactivity and inattentiveness, potentially diminishing a child’s ability to learn, the report’s authors argue.
Each day for 7 weeks, nearly 300 youngsters in England—half around 3 years old, the rest around 8—received purple drinks. The drinks’ color and taste never varied, but for 2 randomly assigned weeks, each child got drinks with a bonus: Either of two different mixes of food colorings, together with sodium benzoate, a general food preservative. Amounts of the additives were scaled to mirror what is found in a typical child’s diet.
Surveys filled out by parents, teachers, and researchers who sat in on classroom or day care activities yielded similar findings, notes Jim Stevenson of the University of Southampton, England, who directed the study. On weeks the kids had downed additive-laced drinks, and on those weeks only, “the hyperactivity score was elevated in both age groups—and for both drinks.”
This heightened activity level didn’t persist into the following week, indicating the effect “is very reversible,” the psychologist says. The average increase attributable to the additives was about a tenth as large as the score separating normal children from those with clinically diagnosed attention-deficit hyperactivity disorder. His team’s findings appear in the Nov. 3 Lancet.