Thumyat Noe ’23
Green tea is one of the most consumed beverages in the world. Consumption of green tea is associated with health benefits such as improved mental health, better global cognition memory, and reduced risk of neurocognitive disorders. Researchers have attributed beneficial effects of drinking green tea to catechins which are flavonoids with antioxidant properties. During the manufacturing and brewing processes, green tea catechins undergo epimerization or conversion to their corresponding isomers which researchers believe have neuroprotective effects. Brain aging is a major global health concern which prompted scientists to study the effects of drinking green tea on cognitive function. Researchers at the Amorepacific R&D Center investigated the effects of high-temperature-processed green tea extract on neuronal oxidative damage and neurocognitive functions in an in vitro study and a clinical study.
In the in vitro study, researchers obtained neuroblastoma cells from the Korean Cell Line Bank and treated the cells with either dimethyl sulfoxide or green tea extract. Researchers then observed neuronal growth in the cells to study the effects of green tea extract on neuronal oxidative damage. In the clinical study, after recruiting a total of 44 middle-aged and old-aged subjects, researchers randomly assigned the participants to take capsules of either the green tea extract or placebo daily for 8 weeks. Then researchers performed subjective questionnaires and cognitive function assessments at the beginning and 8 weeks after the treatment.
Results of in vitro study show that green tea extract reduced neuronal projections in cells and abolished oxidative stress-induced neuronal cell death. Oxidative stress is involved in neurodegeneration and brain aging, therefore, reduction of oxidative stress by green tea extract may be a promising way to combat aging-related cognitive decline. In the clinical study, the group that took capsules of green tea extract showed decreased stress levels and significant improvements in global cognitive functions. Furthermore, the same group reported fewer subjective memory complaints after the treatment. Improvements in cognitive function can be explained by green tea extract’s ability to prevent oxidative stress in cells.
The overall findings from this study strongly suggest that drinking green tea may prevent aging-related cognitive decline. Future clinical studies may include a larger sample size and consider studying the underlying mechanisms of how green tea improves cognitive functions.
 G. Kwon, et. al., Effect of epimerized catechins- rich green tea extract on global cognitive function in healthy individuals: a pilot study. Journal of Food and Nutrition Research 8, 139-148 (2020). doi: 10.12691/jfnr-8-3-4
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