1. Introduction
protein-rich milk
Background: Accumulating evidence has shown that protein-rich milk drinks can rapidly improve cognitive performance. However, the optimum doses of milk protein that are needed to improve cognitive function remain to be investigated. Objective: This study aimed to determine whether acidified milk drinks with 10-g and 15-g milk protein have acute benefits on key cognitive functions in healthy young adults. Design: In this double-blinded randomized control trial, 66 young adults were randomly assigned to one of three groups (0-g, 10-g, and 15-g milk protein groups). Key cognitive functions (processing speed, inhibition, shifting, updating, and working memory capacity) were assessed before and 15 and 60 min after the drink intake. Results: We found that the shifting performance improved at 15 min after intake of the acidified 10-g and 15-g milk protein drinks compared to intake of the 0-g milk protein drink, and this acute effect of the acidified 15-g milk protein drink lasted for 60 min. In addition, updating performance improved at 60 min after intake of the acidified 10-g and 15-g milk protein drinks compared to intake of the 0-g milk protein drink. Conclusion: Our findings suggest that the acidified 10-g and 15-g milk protein drinks have an acute benefit on shifting and updating performance in healthy young adults.Proteins are important for maintaining cognitive health [Proteins are widely available from foods such as meats, beans, and eggs. Milk protein is a particularly high-quality protein source [Previous intervention studies reported that a single shot of milk protein intake improved cognitive functions [Although the previous study indicated the possibility that an acidified milk protein drink would improve cognitive performance [In this study, we used acidified 10-g and 15-g milk protein drinks. There were several reasons for these doses. Firstly, previous studies indicate that intake of an acidified 10-g milk protein drink can rapidly increase essential amino acid levels [To address the abovementioned unresolved issues, we conducted an RCT using two different doses of an acidified milk protein drink (10-g and 15-g) and compared this to a 0-g protein control drink. We measured key cognitive domains, such as processing speed, executive function (inhibition, shifting, and updating), and working memory capacity, at 15 and 60 min after consumption. In addition, we assessed the fasting glucose and glucose at each time point. The purpose of this study was to investigate the time course of the acute benefits of acidified 10-g and 15-g milk protein drinks on key cognitive functions. In this study, we recruited young healthy adults. Previous research using an acidified milk protein drink has shown the acute improvement of simple calculation performance in healthy young adults [