Effects of green tea consumption on cognitive dysfunction: An exploratory clinical study
Author: K. Ide and N. Wakamiya and M. Park and N. Takuma and S. Fujii and A. Nakahara and T. Suzuki and J. Nakase and Y. Ukawa and Y.M. Sagesaka and H. Yamada
Background: In rapidly aging societies worldwide, the number of patients with disorders marked by cognitive dysfunction, such as Alzheimer's disease, is gradually increasing; however, thus far, no fundamental curative therapy has been established. Green tea, whose major constituents are catechins and theanine, is known to have various health benefits for humans. However, the effects of green tea consumption on cognitive dysfunction remain to be clinically verified. Objective: To conduct a clinical study to investigate the effects of green tea consumption on cognitive dysfunction. Patients and methods: Twelve elderly nursing home residents (2 men, 10 women; mean age, 88 years) with cognitive dysfunction (Mini Mental State Examination [MMSE] score: <28) were recruited. Written informed consent was obtained from the patients and caregivers. The patients were asked to consume green tea powder (2 g/day [containing 227 mg of catechins and 37 g of theanine]; manufactured by ITO EN Ltd., Tokyo) for 3 months. Cognitive function was assessed by performing MMSE, and serum lipid levels were measured. Results: The MMSE scores (mean ± S.D.) significantly improved after the intervention (before intervention, 15.3 ± 7.7; after intervention, 17.0 ± 8.2; p = 0.025), especially for the category recent memory. Regarding serum lipid levels, low-density lipoprotein (LDL)-cholesterol levels remained unaltered, but triglyceride levels decreased significantly (before intervention, 124 ± 80 mg/dL; after intervention, 103 ± 57 mg/ dL; p = 0.041). Conclusion: These results suggest that green tea consumption may be effective in improving cognitive function, and additional confirmatory long-term controlled studies are needed.
