Lunch and Cognitive Performance in School Children: The Crossover Intervention Trial CogniDo

Background: The Cognition Intervention Study Dortmund (CogniDo) for the first time examines the question of lunch and cognition in children and so far suggests rather weak positive effects of having lunch in contrast to not having lunch on single cognition parameters. Studies on breakfast point to associations of the glycemic index (GI) of the meal and cognitive functioning. Therefore, our recent study CogniDo GI examined if a lunch with a low GI would favor cognition in school children.

Methods: The randomized crossover intervention trial performed at a large comprehensive school (Gelsenkirchen, Germany) included 212 children (5th, 6th grades), randomized within their class. Group 1 received lunch with a high GI ad libitum on the first study day and lunch with a lower GI on the second day 1 week later. Group 2 had the reversed sequence. The GI of the meal (rice with sauce Bolognese) was modified via rice with high GI (86) and lower GI (62) determined in a research laboratory. The cognitive parameters task switching, working memory, updating and alertness were tested.

Results: No significant differences of the tested cognition parameters were found between lunch with either a high or a lower GI.

Conclusion: The results of the earlier CogniDo studies together with the new study do not provide convincing evidence of short-term effects of lunch on cognitive performance in school children. Our computerized test battery which was feasible in every-day life could be applicable in neuropediatric research as well.

*Funded by the Uniscienta Stiftung. Landstrasse 25, 9490, Vaduz.