Effects of Heat-Treated Green Tea Extract on Memory Function and Default Mode Network Connectivity in Individuals...

Given the increasing interest in the potential cognitive benefits of green tea, this study evaluated the efficacy of processed green tea products as nootropic agents. We conducted a 12-week, randomized, double-blinded, placebo-controlled trial to assess the effects of heat-treated green tea extract (HT-GTE) supplementation on memory performance in individuals with subjective memory impairment (SMI). A total of 80 participants with SMI (mean age 49.6 ± 5.6 years) were randomly assigned to either the HT-GTE group (n = 40) or the placebo group (n = 40). Memory performance was assessed using standardized composite scores at baseline and week 12. Additionally, we examined changes in functional connectivity (FC) within the default mode network (DMN), a key resting-state network associated with memory function, at both time points. Compared to the placebo group, the HT-GTE group demonstrated significant improvements in memory function after 12 weeks, as evidenced by a greater increase in composite scores (z = 2.535, P for interaction = .011). Furthermore, the HT-GTE group exhibited increased FC within the right precuneus region of the DMN (z = 2.554, P for interaction = .011). These findings underscore the potential of HT-GTE supplementation to enhance memory performance and FC within the DMN in middle-aged individuals with SMI, offering valuable insights into the cognitive benefits of green tea.