ITO EN, Ltd. and MCBI Inc. jointly conducted a clinical trial to assess matcha's inhibitory effects on the decline of cognitive function in the older adults with mild cognitive impairment (MCI), the pre-stage of dementia, or subjective cognitive decline (SCD). Researchers found that the daily intake of matcha was associated with an improvement in sleep quality and social cognitive function. The joint research team published the results of their research at the Alzheimer's Association International Conference (AAIC) held in San Diego, California, USA on August 2, 2022.

Matcha has been popular in Japan for a very long time. The beverage contains catechin and theanine. Previous studies suggested that catechin reduces blood cholesterol levels and body fat and also improves working memory, and theanine relieves stress and improves sleep and working memory.

Additionally, it has been reported that the short-term intake of matcha can increase attentiveness and the accuracy of decision making in the middle-aged and older adults. In this clinical study, participants undertook cognitive function evaluations, blood-based biomarkers, kinetic analyses (blood tea component levels), neuroimaging (fNIRS and Amyloid PET imaging) and sleep evaluations before and after the intervention involving the long-term intake of matcha to comprehensively analyze the effects of matcha and changes in biomarkers. Methods: This trial was conducted as a double blind placebo-controlled randomized comparative study of 99 participants diagnosed with mild cognitive impairment (MCI), the pre-stage of dementia, or subjective cognitive decline (SCD), the preclinical stage of Alzheimer's disease, selected from 939 participants aged 60 to 85 to investigate the effect of the long-term intake of matcha on cognitive function, etc.

Participants in the matcha group took matcha capsules (2 g matcha per day) for 12 months while participants in the placebo group used capsules filled with colored corn starch. Changes in the endpoints from the start of the study to Month 12 were statistically validated using mixed effects models. Effects of matcha on quality of sleep confirmed and social cognitive function (perception of emotions based on facial expression).

The Pittsburgh Sleep Quality Index (PSQI) was used to evaluate quality of sleep, revealing a trend toward a decrease in PSQI scores and improve quality of sleep in the matcha group. As a result of neuropsychological tests (e.g., MMSE-J, MoCA-J) that are used for dementia and MCI screening, there was no difference in the cognitive function scores of the matcha group and the placebo group. When cognitive function was evaluated using Cognitrax (CNS Vital Signs, LLC) for each brain region, the matcha group showed a significant improvement in social cognition assessed with a facial expression recognition test, specifically, the precision of their perception of emotions based on facial expression compared to the placebo group (the figure on the right).

In research and development, they view the value of tea with a scientific eye, and engage in research and development to propose lifestyle improvements to enable people to live fulfilling lives in the era of the 100-year life expectancy. They believe that it is extremely important for elderly people to quality of sleep and maintain their social cognitive function (perception of emotions based on facial expression) so that they experience a better quality of life in a super-aged society. The research team will elucidate the relationship between the daily intake of matcha and improve quality of sleep or improved social cognitive function, which were observed in the study, and the mechanism for these effects.

In addition, the details of other tests will be analyzed. Through the initiative, ITO EN and MCBI will contribute to the realization of healthy and rich living and a sustainable society through efforts to enable the elderly living in super-aging society to live fulfilling lives.