Many children rely on sugary drinks as a regular part of their daily lives. We know that they can affect their physical health but we don't know how it affects their brain health.
A quarter of 11-year-olds in Belgium currently drink at least one soft-drink per day. The results of a double-blind, placebo controlled trial with Belgian preschoolers suggests that sugary drinks can have a strange effect on class performance.
This rigorous experiment is the first to look at the immediate effects sugary drinks have on student achievement. The findings suggest that there may be key sex differences between how students respond to glucose, at least as children. Our brains consume more energy than adults, which could explain why the results.
For example, young male preschoolers experienced a significant drop in test scores when they drank sugary drinks. Young boys who had consumed 35 grams of sugar initially displayed a calm state, but after about an hour this calm state gave way to restlessness.
The sugar didn't seem to affect the pre-schoolers of female gender; in fact, they actually scored higher in math.
Fritz Schiltz, an applied econometrician from Katholieke Universiteit Leuven in Belgium, stated that "the results clearly indicate a causal effect of sugary drinks on kids' behavior and test scores."
"The implications of this on in-class performance have significant policy implications. Sugary drinks are still widely sold in schools, and sugary drink consumption is generally higher among low-income children than among those from high-income families.
The authors claim that their findings could partially explain why lower socioeconomic boys perform less in school. They also drink the most sugar.
To confirm that this hypothesis is true for other times and places around the globe, more research will be required.
Some research shows that high-glucose foods and drinks can increase cognitive performance. However, these studies are usually limited to the elderly or adults.
The link between child's glucose intake, cognitive performance and their brain function is however, largely inconclusive.
It is surprising that so many sugary drinks are consumed daily by children, but little research has been done on the cognitive effects. This is the leading example of this research in Belgium.
These two experiments involved 462 preschool-aged children. Half of them were given a lemon-flavored soft drinks with 35 grams sugar, and the other half were given artificially sweetened beverages with "zero" sugar.
Ten preschool classes were included in the first randomized trial. Students were tested on math skills prior to drinking a beverage and again 45 minutes later.
The second randomized trial involved 15 classes. Students were tested on math skills prior to drinking, then again after 30 minutes, an hour, or two hours.
These times are explained by the authors to encompass the sugar "high", and "crash," that can occur after children consume large amounts of glucose.
It was interesting to note that sugary drinks took approximately 45 minutes for the benefits to kick in. The benefits began to fade after two hours.
However, math scores for boys tend to drop an hour after they have had a sugary drink. The downsides were evident even after just two hours.
The authors conclude that "our results suggest that the adverse and persistent effects on boys' test scores, teachers' classrooms, and teacher's classrooms are unlikely to be outweighed by a marginal rise in resources from sugary drinks sold at school."
Although the team is unable to determine why sugary drinks would affect a child's math scores, they believe it may have something to do stress, sugar intake, and student achievement.
Boys may be feeling restless after drinking sugary beverages.
The study is unique in its type, and the results cannot be compared with anything else. It's difficult to place them in context.
However, both the trials that were designed to test this hypothesis showed no significant differences in sex. These findings should be investigated further.
If we are to understand the impact of diets on learning, it is crucial that we find out more.
Health Economics published the study.