the evolving mind

[This is the 2nd part in a 4-part series. Intro here.]

Sugar makes children behave hyperactively. If I had a dime for every time I’ve heard a parent repeat this nugget of nonsense, I’d have a lot of dimes. But I can see how parents find evidence to fill this particular “belief-net.” Any moment they observe a child acting energetically (something children do with great frequency) following the consumption of a sugary food — bingo! Supporting information.

Meanwhile, the times a child eats sugar and continues to behave
as he or she was before the sugar, or even takes a nap, this instance lights up nothing in the parent’s mind. And just as opposing cases are neglected, so are alternative cases. When little Bobby does his Tasmanian devil imitation following the consumption of a slice of pizza, the parent does not think, “Gee, pizza can make kids hyper, too.”

An adult who holds the sugar-makes-kids-hyper belief could be accused of being less rational on two counts. First, he (or she) has fallen prey to the confirmation bias. Most likely not intentionally, but naturally. Second, he is probably relying upon personal observation and hearsay, which are weak sources of data. A better source would be scientific studies.
And the research clearly says it isn’t so.

Way back in 1995 a meta-analysis of research conducted on the alleged relationship between sugar and behavior appeared in the pages of the Journal of the American Medical Association. The conclusion: “Sugar does not affect the behavior or cognitive performance of children.”(1)

It is possible that when some children receive a special treat they become excited for psychological versus metabolic reasons. Maybe they have heard adults claim that sugar leads to hyperactivity and are merely fulfilling a prophecy. To tease apart these influences, placebo controlled,
double-blind studies are necessary.

In 1996 the journal Critical Reviews in Food Science and Nutrition published the finding that twelve such studies failed to provide any evidence that “sugar ingestion leads to untoward behavior” in children with ADHD or normal children. (2) Research that replicates the finding of others adds substantial heft to the information.

If healthy human bodies responded dramatically to sugar, orange juice would be on every parent’s list of controlled substances. It’s loaded with simple sugars. Diabetics stave off episodes of hypoglycemia by drinking OJ. Yet I don’t think you’ll ever hear a parent say, “No, Tammy. No squeezed citrus for you. I don’t want you thumping the other kids on your bus ride to school.”

A full decade after medical/scientific research refuted the link between sugar and hyperactivity I conducted an informal survey of family and friends, seeking their opinion as to whether sugar causes hyperactivity in children, without revealing what I knew. In the responses to my e-mail query, I discovered that the sugar-hyperactivity link was still bandied about and believed. A number provided testimonials that yes, they have personally witnessed the phenomenon. All those canvassed had college degrees and none lived in communes cut-off from the free trade of ideas.

Why does the belief persist? First, the research findings are not getting
through to the general public. Second, the information individuals are basing their conclusion upon is biased.

-

(1) M. L. Wolraich; D. B. Wilson; J. W. White, “The effect of sugar on behavior or cognition in children. A meta-analysis,” JAMA. 1995;274: 1617-1621.
(2) Krummel, D.A., Seligson, F. H., & Guthrie, H. A. 1996. “Hyperactivity: is candy causal?” Critical Reviews in Food Science and Nutrition, 36 (1-2), 31-34.
Note: More recent research has linked additives used in sodas, such as sodium benzoate, to hyperactivity in children. But not the sugar.

Technorati Links: belief, critical thinking

Trackback URI | Comments RSS