Institute of Biomedicine, Pharmacology, Medical Nutrition Physiology, PO Box 63, FIN-00014 University of Helsinki, Finland.
Br J Nutr. 2013 Oct;110(7):1336-46. doi: 10.1017/S0007114513000238. Epub 2013 Mar 18.
Milk proteins are the main components of everyday feeding and demonstrate a promising potential to change the mental condition. However, the effects of milk proteins after prolonged use remain poorly understood. The aim of the present study was to compare the effects of two whey proteins (alpha-lactalbumin (alpha-lac) and native whey) with casein on social and individual behaviour in mice. During a 30 d-long dietary intervention, male C57BL/6J mice had ad libitum access to an experimental diet containing 17% (w/w) of one of three protein sources: a-lac, native whey or casein. Mice had voluntary access to a running wheel. Social behaviour (group and resident-intruder activity) was tested at baseline and at the end of the intervention. Half of each dietary group was then withdrawn from the diet and running wheel for 7 d, and social activity and individual behaviour tests (open field, elevated-plus maze, light–dark box and forced swimming) were performed, to evaluate anxiety and depression-like status. The study shows that the long-term ingestion of whey proteins may modulate behaviour when compared with casein. Diet enriched with a-lac exhibited anxiolytic and antidepressive activities while the whey diet improved sociability. The differences between the diet groups were pronounced under the running wheel and the withdrawal of the experimental diet, suggesting that the beneficial effects of the milk proteins are clearer in stressful situations. Diet-induced behavioural changes remained visible for a week after feeding, which suggests that the proteins of the milk whey fraction have prolonged efficacy on the mental state of mice.
乳蛋白是日常饮食的主要成分，具有改变精神状态的巨大潜力。然而，长期使用乳蛋白的效果仍知之甚少。本研究旨在比较两种乳清蛋白（α-乳白蛋白（alpha-lac）和天然乳清）与酪蛋白对小鼠社交和个体行为的影响。在 30 天的饮食干预期间，雄性 C57BL/6J 小鼠可自由摄入含有三种蛋白质来源之一（17%（w/w））的实验饮食：alpha-lac、天然乳清或酪蛋白。小鼠可自由使用跑步轮。在基线和干预结束时测试社交行为（群体和居民入侵者活动）。然后，每组的一半从饮食和跑步轮中撤出 7 天，并进行社交活动和个体行为测试（旷场、高架十字迷宫、明暗箱和强迫游泳），以评估焦虑和抑郁样状态。研究表明，与酪蛋白相比，长期摄入乳清蛋白可能会调节行为。富含 alpha-lac 的饮食表现出抗焦虑和抗抑郁作用，而乳清饮食则改善了社交能力。在跑步轮和实验饮食撤出的情况下，饮食组之间的差异明显，这表明在压力情况下，牛奶乳清部分的蛋白质的有益效果更为明显。饮食诱导的行为变化在喂养后一周仍然可见，这表明乳清蛋白对小鼠的精神状态具有持久的疗效。
