Smith Andrew P, Sutherland David, Hewlett Paul
Centre for Occupational and Health Psychology, School of Psychology, Cardiff University, 63 Park Place, Cardiff CF10 3AS, UK.
Nutrients. 2015 Oct 28;7(11):8887-96. doi: 10.3390/nu7115441.
Inulin is a natural food component found in many plants that are part of the human diet (e.g., leeks, onions, wheat, garlic, chicory and artichokes). It is added to many foods and is used to increase dietary fibre, replace fats or carbohydrates, and as a prebiotic (a stimulant of beneficial bacteria in the colon). Oligofructose, which is also present in these foods, produces similar effects and most research has used a combination of these products. A previous study (Smith, 2005) investigated the effects of regular consumption of oligofructose-enriched inulin on wellbeing, mood, and cognitive performance in humans. The results showed that oligofructose-enriched inulin had no negative effects but that it did not improve wellbeing, mood, or performance. The aim of the present study was to examine the acute effects of oligofructose-enriched inulin (5 g) over a 4 h period during which the participants remained in the laboratory. A double blind placebo (maltodextrin) controlled study (N = 47) was carried out with the order of conditions being counterbalanced and the two sessions a week apart. On each test day mood and cognitive performance were assessed at baseline (at 8:00) and then following inulin or placebo (at 11:00). Prior to the second test session (at 10:30) participants completed a questionnaire assessing their physical symptoms and mental health during the test morning. The inulin and placebo were provided in powder form in 5 g sachets. Volunteers consumed one sachet in decaffeinated tea or decaffeinated coffee with breakfast (9:00). Questionnaire results showed that on the day that the inulin was consumed, participants felt happier, had less indigestion and were less hungry than when they consumed the placebo. As for performance and mood tasks, the most consistent effects were on the episodic memory tasks where consumption of inulin was associated with greater accuracy on a recognition memory task, and improved recall performance (immediate and delayed). Further research is required to identify the mechanisms that underlie this effect with glucose metabolism being one candidate.
菊粉是一种天然食物成分，存在于许多作为人类饮食一部分的植物中（例如韭菜、洋葱、小麦、大蒜、菊苣和洋蓟）。它被添加到许多食物中，用于增加膳食纤维、替代脂肪或碳水化合物，还用作益生元（一种刺激结肠有益细菌的物质）。这些食物中还存在的低聚果糖也有类似作用，大多数研究使用的是这些产品的组合。之前的一项研究（史密斯，2005年）调查了经常食用富含低聚果糖的菊粉对人类幸福感、情绪和认知表现的影响。结果表明，富含低聚果糖的菊粉没有负面影响，但也没有改善幸福感、情绪或表现。本研究的目的是检验富含低聚果糖的菊粉（5克）在4小时内的急性效应，在此期间参与者待在实验室里。进行了一项双盲安慰剂（麦芽糊精）对照研究（N = 47），条件顺序进行了平衡，两次试验相隔一周。在每个测试日，在基线（8:00）以及服用菊粉或安慰剂后（11:00）评估情绪和认知表现。在第二次测试时段之前（10:30），参与者完成一份问卷，评估他们在测试上午的身体症状和心理健康状况。菊粉和安慰剂以粉末形式装在5克的小袋中。志愿者在早餐（9:00）时用无咖啡因茶或无咖啡因咖啡冲服一袋。问卷结果显示，在食用菊粉的那天，参与者比食用安慰剂时感觉更快乐、消化不良更少且饥饿感更轻。至于表现和情绪任务，最一致的效应出现在情景记忆任务中，食用菊粉与识别记忆任务的更高准确性以及更好的回忆表现（即时和延迟）相关。需要进一步研究以确定这种效应背后的机制，葡萄糖代谢是一个候选因素。
