For participants who had the 10-g or the 15-g milk protein drinks, their ‘shifting’ performance had improved at 15 minutes while ‘updating’ performance improved at 60 minutes.
Shifting is defined as the ability to flexibly shift focus between stimuli, while updating is the ability to maintain and manipulate information temporarily.
Neither effect was observed in the placebo group.
For the 15-g group, the study found that measured improvement in their cognitive performance had lasted longer at 60 minutes, while this was not observed for the 10-g group.
The researchers come from Tohoku University in Japan, Anglia Ruskin University and University of Reading in the United Kingdom.
Their paper received funding support from Meiji Co., Ltd. R.N. under their Grant-in-Aid for Scientific Research on Innovative Areas initiative.
While the report specified that Meiji was not involved in the research and writing of the paper, Meiji’s products were consumed by the participants to assess the study objective.
To assess whether acidified, protein-rich milk drinks had an impact on cognitive functions in healthy young adults, a double-blinded randomized control trial was conducted.
66 participants, aged 20 – 30 years, were randomly assigned to one of the three groups - 0-g, 10-g and 15-g groups. The experiment and assessments were conducted within a day.
Participants were directed to consume drinks manufactured by the R&D division of Meiji Co., Ltd based in Tokyo, Japan. Milk protein concentrate was optimised for the 10-g and 15-g milk protein drinks.
Prior to the drink consumption, at the 15-minutes’ mark, and at the 60-minutes’ mark after consumption, respectively, the participants had their cognitive performance assessed.
The assessments were conducted over an open-source software, PsychoPY. Specific executive functions that were assessed included processing speed, shifting, inhibition, updating, and working memory capacity.
Previous literature had shed insights into the role of amino acids in improving cognitive performance.
“Milk protein contains a high proportion of amino acids, and the acidified milk drink also contains amino acids. It is possible that changes in amino acid levels would have a critical role in the acute beneficial effects of acidified milk proteins. Indeed, accumulating studies have demonstrated that amino acids play an important role in maintaining and improving cognitive function,” the researchers reported.
The researchers also rationalised their choice of experimenting with 10-g and 15-g amounts in their study as “previous studies indicate that intake of an acidified 10-g milk protein drink can rapidly increase essential amino acid levels.”
The study is limited by the lack of clarity in the actual duration that the benefits of milk protein would last and the lack of biological measurements.
“This finding could have relevance to clinical situations, given that executive functions decline in aging and clinical populations. Future research could investigate whether acidified milk protein can improve executive functions in clinical populations,” the paper concluded.
“Acute Benefits of Acidified Milk Drinks with 10-g and 15-g Protein on Shifting and Updating Performances in Young Adults: A Randomized Controlled Trial”
Authors: Nouchi, R., et al.