PSYCHOLOGY
Parents blame sugar for causing kids’ hyperactivity, but the evidence suggests it’s not the culprit.
Sugar is blamed for kids’ hyperactivity, but it may not be the culprit after all
The manufacturer of Red Bull used to claim the energy drink “gives you wings”. This was because, as it also used to claim, it “improves performance, especially during times of increased stress or strain. Increases endurance. Increases concentration and improves reaction speed. Stimulates the metabolism.” That was until a court ordered it to rewrite its marketing.
The claims sounded plausible. After all, our brains account for less than 5% of our body weight but about a quarter of the glucose our body uses for energy in the course of a day. We also know coffee’s reputation as an early-morning pick-me-up.
Unfortunately, most energy drinks contain no more caffeine than the average cup of coffee. More important, the pick-me-up benefits of coffee (and other caffeinated drinks) are also not what they’re cracked up to be. Those people who regularly drink caffeinated beverages are the most likely to benefit from them. This is because, instead of making you the best you can be, a morning coffee makes you as good as you would be if you weren’t experiencing caffeine withdrawal.
But what about the sugar content? Sugar gives you energy, and most of us know the terror of a room full of blue-icing-fuelled toddlers. I admit to believing this myself, but as a scientist with access to a well-stocked library and a penchant for procrastination, I’ve looked into it.
The intuitively sensible idea that sugar can cause hyperactivity has been the subject of a fair amount of testing. The challenge test is one example. Ensure the child is sugar-free for a week or more and take some baseline measurements of behaviour and performance. Then give them either sugar or a sugar substitute and watch what happens.
The results are underwhelming, to say the least. Many more studies show no difference in behaviour, and at least one intriguing study suggests some people perform better on sugar – specifically, “delinquents” who are already hyperactive. The benefits, however, related to concentration rather than behaviour. This may sound odd, but it’s not inconsistent with the fact that many medical treatments for attention deficit hyperactivity disorder (ADHD) are actually stimulants, such as dexamphetamine and methylphenidate (better known as Ritalin).
So, if there’s so little robust evidence, why do parents fear toddler birthday parties? There are at least two things going on. First, sugar does provide energy, which means you’re fuelling the birthday-party excitement. Our bodies will burn through blood glucose if we need it for running around and swinging from monkey bars, but if we’re not active, it will store it. Second, because parents think sugar makes kids hyperactive, they expect it to happen, so that’s what they see (confirmation bias, take a bow).
It may also be that the problem is not the sugar in the icing, but the vibrant colourings. There’s no convincing evidence that food dyes cause ADHD, but there is cautious reason to think food dyes can cause short-term increases in hyperactivity. The extent
Sugar gives you energy, and most of us know the terror of a room full of blueicing-fuelled toddlers.
is not clear, and it’s further confused by a concern that sodium benzoate
– a common preservative used in many of the same drinks that use the suspect colourings – also seems to be associated with hyperactivity.
Regardless, it seems reasonable to claim that sugary energy drinks add to your energy stores. What probably caused legal problems for Red Bull were its claims regarding concentration and reaction speed. They were starting to sound a bit like therapeutic claims, but there wasn’t much evidence to support them. Remember, they’re metaphorical wings.