Schröder Maike, Müller Katrin, Falkenstein Michael, Stehle Peter, Kersting Mathilde, Libuda Lars
Research Institute of Child Nutrition (FKE) Dortmund, University of Bonn, Germany.
University of Applied Sciences (DHfPG), Institute for Prevention and Public Health, Saarbrücken, Germany.
Physiol Behav. 2015 Dec 1;152(Pt A):307-14. doi: 10.1016/j.physbeh.2015.09.025. Epub 2015 Sep 30.
Studies indicate that eating lunch impairs some aspects of adults' cognitive functioning. However, the short-term effects of lunch on children's executive functions (EF) have not been examined. The Cognition Intervention Study Dortmund PLUS (CogniDo PLUS) investigated (a) short-term effects of lunch on EF in children and (b) whether the postprandial cortisol increase mediates putative lunch effects on EF performance.
5th and 6th grade students of a comprehensive school in Gelsenkirchen (Germany) participated in the randomized crossover intervention study. On Day 1 of the study, Group 1 did not eat lunch,whereas Group 2 received lunch ad libitum. One week later on Day 2 the groups were treated vice versa. At the beginning of the afternoon lessons, the EF parameters task switching,working memory updating and inhibition were tested using a computerized test battery. Saliva samples were used to measure cortisol directly before lunch and again at the beginning of the cognitive assessment. Of the 215 initially recruited children 21 dropped out of the study due to illness or absence on one of the two test days.
Lower ratios of false alarms in the working memory updating function were observed when children who ate lunch than for children who had no lunch (8.2% (lunch) versus 9.4% (no lunch), p b 0.01). Parameters of task switching and inhibition did not differ between children who ate lunch compared to children who had no lunch. Stratification according to postprandial cortisol increase showed that the subgroup with a high increase had lower ratios of false alarms after eating lunch, while false alarm values did not change in the group with a low increase.
In contrast to findings in adults, the results indicate that children's EF are not impaired by lunch under true-to-life conditions. On the contrary, the current study even indicates beneficial effects of lunch intake for the working memory updating. The postprandial cortisol increase in the range observed in our sample does not seem to be related with negative effects on the performance of EF, but even seem to mediate the beneficial effect of lunch on the working memory updating.
研究表明，吃午餐会损害成年人认知功能的某些方面。然而，午餐对儿童执行功能（EF）的短期影响尚未得到研究。多特蒙德认知干预研究PLUS（CogniDo PLUS）调查了（a）午餐对儿童EF的短期影响，以及（b）餐后皮质醇升高是否介导了午餐对EF表现的假定影响。
德国盖尔森基兴一所综合学校的五年级和六年级学生参与了这项随机交叉干预研究。在研究的第1天，第1组不吃午餐，而第2组随意吃午餐。一周后的第2天，两组的处理方式互换。在下午课程开始时，使用计算机化测试组对EF参数任务转换、工作记忆更新和抑制进行测试。在午餐前和认知评估开始时采集唾液样本以测量皮质醇。在最初招募的215名儿童中，有21名因在两个测试日中的某一天生病或缺席而退出研究。
与没吃午餐的儿童相比，吃午餐的儿童在工作记忆更新功能中的误报率更低（8.2%（吃午餐）对9.4%（没吃午餐），p<0.01）。吃午餐的儿童与没吃午餐的儿童在任务转换和抑制参数上没有差异。根据餐后皮质醇升高情况进行分层显示，升高幅度大的亚组在吃午餐后的误报率较低，而升高幅度小的组中误报值没有变化。
与成年人的研究结果相反，这些结果表明，在真实生活条件下，午餐不会损害儿童的EF。相反，当前研究甚至表明摄入午餐对工作记忆更新有有益影响。在我们样本中观察到的餐后皮质醇升高范围似乎与对EF表现的负面影响无关，甚至似乎介导了午餐对工作记忆更新的有益作用。
