Effects of Heat-Treated Green Tea Extract on Memory Function and Default Mode Network Connectivity in Individuals with Subjective Memory Impairment: A Randomized, Double-Blinded, Placebo-Controlled Trial
Yoonji Joo, Hyeonji Lee, H. Jeong, C. Suh, Haejin Hong, Yejin Kim, Seoyoung Yu, Chaerin Lee, Youngeun Shim, Sujung Yoon
Journal of medicinal food April 24, 2025 DOI: 10.1089/jmf.2024.k.0260 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized, double-blind, placebo-controlled trial Peer reviewed |
|---|---|
| Sample size | 80 |
| Population | Middle-aged adults with subjective memory impairment (mean age 49.6 ± 5.6 years) |
| Intervention | Heat-treated green tea extract (HT-GTE) |
| Duration | 12 weeks |
| Measures | standardized composite memory scores, functional connectivity (FC) within the default mode network (DMN) |
| Topics | Default mode network |
| Key findings | Heat-treated green tea extract improved standardized composite memory scores more than placebo over 12 weeks (z = 2.535, interaction P = .011) and increased functional connectivity in the right precuneus region of the default mode network (z = 2.554, interaction P = .011). The authors conclude that HT-GTE may enhance memory and default mode network connectivity in middle-aged individuals with subjective memory impairment. |
Abstract
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.
Comparable studies
Other randomized controlled trials on default mode network, most cited first.
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|---|---|---|---|
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| Antidepressants Normalize the Default Mode Network in Patients With Dysthymia Subjects with dysthymic disorder and healthy control participants aged 18 to 53 years | 2013 | Randomized controlled trial | n = 41 |
| Functional Connectivity Measures After Psilocybin Inform a Novel Hypothesis of Early Psychosis Healthy volunteers | 2012 | Within-subject, placebo-controlled experimental study | n = 15 |