Drinking glucose improves listening span in students who miss breakfast

Low blood sugar level resulting from fasting has been shown to reduce perfo rmance on a number of cognitive tasks. In this study, 80 non-diabetic A-lev el students missed breakfast. They completed a version of Daneman and Carpe nter's Listening Span Test at 9.00 a.m. Half were then given a drink contai ning glucose, while the other half received a saccharine drink matched for taste. After 20 minutes, both groups completed another form of the Listenin g Span Test. A subset of the sample had their blood glucose levels determin ed immediately before the drink and again before the second application of the test. Blood glucose levels did not change, but listening span performan ce significantly improved after a glucose drink yet not after a saccharine drink. It is concluded that missing breakfast does not seriously affect blo od sugar levels in healthy young students, but listening span performance w hich is a good predictor of listening comprehension is improved when fastin g individuals imbibe a glucose-rich drink, although not when a saccharine d rink is drunk. Ideally students should eat breakfast, but if this is omitte d, then a glucose snack or drink before the first class may reverse any adv erse effects.