Impact of lunch with carbohydrates differing in glycemic index on children's cognitive functioning in the late postprandial phase: a randomized crossover study

Alina Drozdowska,Kathrin Sinningen,Lars Libuda,Anette E Buyken,Henrik Rudolf,Mathilde Kersting,Thomas Lücke,Michael Falkenstein

doi:10.1007/s00394-021-02766-y

Alina Drozdowska, Kathrin Sinningen + Show 6 more

Open Access

https://doi.org/10.1007/s00394-021-02766-y

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Abstract

PurposeStudies about effects of lunch dietary Glycemic Index (GI) on cognition of schoolchildren are scarce. Our previous CogniDo GI study found no changes of cognition in the early postprandial phase after consumption of two rice types with medium vs. high dietary GI for lunch (i.e., 45 min after starting lunch). This study investigated whether the dietary GI of lunch has an impact on cognition of schoolchildren in the late postprandial phase, 90 min after lunch.MethodsA randomized, 2 × 2 crossover intervention study was conducted at a comprehensive school with 5th and 6th grade students. Participants (n = 212) were randomly assigned to either sequence 1 or 2. In the first period, participants of sequence 1 received a dish with high GI rice (GI: 79), those of sequence 2 with medium GI rice (GI: 64)—in the second period, 1 week later, vice versa. Computer-based cognitive testing was performed 90 min after lunch examining tonic alertness, visual search and task switching, and working memory. Treatment effects and treatment effects adjusted for estimated lunch glycemic load (GL) were analyzed using a linear mixed model.ResultsThe selected cognitive parameters were not affected by the GI of lunch 90 min after lunch, neither after intention-to-treat nor in the per-protocol analysis. Adjustment for GL also did not change results.ConclusionThe present study revealed no notable differences after the consumption of two rice types with medium vs. high dietary GI for lunch in children’s cognitive function in the late postprandial phase, 90 min after lunch.Clinical trial registrationGerman Clinical Trials Register (DRKS00013597); date of registration: 16/04/2018, retrospectively registered.

Highlights

Remaining concentrated and attentive throughout a school day can be challenging for schoolchildren
Fatty fish consumption and omega-3 fatty acid intake have been associated with improved memory and faster processing speeds [1, 2]; a sufficient water supply was shown to have favorable effects on cognitive performance [3], and some studies indicate that breakfast composition with regard to glycemic carbohydrates might influence cognition in children throughout the morning [4, 5], as well as in adults suffering from impaired glucoregulation [6]
The glycemic load (GL) of the meal consumed with high GI rice (hGI) rice (Jasmin Rice) was significantly higher (Table 1)

Summary

Introduction

Remaining concentrated and attentive throughout a school day can be challenging for schoolchildren. Fatty fish consumption and omega-3 fatty acid intake have been associated with improved memory and faster processing speeds [1, 2]; a sufficient water supply was shown to have favorable effects on cognitive performance [3], and some studies indicate that breakfast composition with regard to glycemic carbohydrates might influence cognition in children throughout the morning [4, 5], as well as in adults suffering from impaired glucoregulation [6]. The reason why carbohydrate-rich foods are thought to influence cognition depending on their GI is that the brain is sensitive to changes in blood glucose concentrations [7]. The existing literature on GI of breakfast and cognition seem to vary depending on the time of testing and the parameters examined

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